1
|
Wang J, Eulgem T. Growth deficiency and enhanced basal immunity in Arabidopsis thaliana mutants of EDM2, EDM3 and IBM2 are genetically interlinked. PLoS One 2024; 19:e0291705. [PMID: 38329997 PMCID: PMC10852260 DOI: 10.1371/journal.pone.0291705] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 01/14/2024] [Indexed: 02/10/2024] Open
Abstract
Mutants of the Arabidopsis thaliana genes, EDM2 (Enhanced Downy Mildew 2), EDM3 (Enhanced Downy Mildew 3) and IBM2 (Increase in Bonsai Methylation 2) are known to show defects in a diverse set of defense and developmental processes. For example, they jointly exhibit enhanced levels of basal defense and stunted growth. Here we show that these two phenotypes are functionally connected by their dependency on the salicylic acid biosynthesis gene SID2 and the basal defense regulatory gene PAD4. Stunted growth of edm2, edm3 and ibm2 plants is a consequence of up-regulated basal defense. Constitutively enhanced activity of reactive oxygen species-generating peroxidases, we observed in these mutants, appears also to contribute to both, their enhanced basal defense and their growth retardation phenotypes. Furthermore, we found the histone H3 demethylase gene IBM1, a direct regulatory target of EDM2, EDM3 and IBM2, to be at least partially required for the basal defense and growth-related effects observed in these mutants. We recently reported that EDM2, EDM3 and IBM2 coordinate basal immunity with the timing of the floral transition by gradually reducing the extent of this defense mechanism prior to flowering. Together with these observations, data presented here show that at least some of the diverse phenotypic effects in edm2, edm3 and ibm2 mutants are genetically interlinked and functionally connected. Our new results show that repression of basal immunity by EDM2, EDM3 and IBM2 limits negative impact on growth and development.
Collapse
Affiliation(s)
- Jianqiang Wang
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
| | - Thomas Eulgem
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, California, United States of America
| |
Collapse
|
2
|
Wang J, Eulgem T. The Arabidopsis RRM domain proteins EDM3 and IBM2 coordinate the floral transition and basal immune responses. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 116:128-143. [PMID: 37347678 DOI: 10.1111/tpj.16364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 06/12/2023] [Indexed: 06/24/2023]
Abstract
The transition from vegetative to reproductive development (floral transition) is a costly process in annual plants requiring increased investments in metabolic resources. The Arabidopsis thaliana (Arabidopsis) PHD finger protein EDM2 and RRM domain proteins EDM3 and IBM2 are known to form chromatin-associated complexes controlling transcript processing. We are reporting that distinct splice isoforms of EDM3 and IBM2 cooperate in the coordination of the floral transition with basal immune responses. These cooperating splice isoforms, termed EDM3L and IBM2L, control the intensity of basal immunity and, via a separate pathway, the timing of the floral transition. During the developmental phase prior to the floral transition expression of EDM3L and IBM2L strongly and gradually increases, while these isoforms simultaneously down-regulate expression of the floral suppressor gene FLC and promote the transition to reproductive growth. At the same time these accumulating EDM3 and IBM2 splice isoforms gradually suppress basal immunity against the virulent Noco2 isolate of the pathogenic oomycete Hyaloperonospora arabidopsidis and down-regulate expression of a set of defense-associated genes and immune receptor genes. We are providing clear evidence for a functional link between the floral transition and basal immunity in the annual plant Arabidopsis. Coordination of these two biological processes, which compete for metabolic resources, is likely critical for plant survival and reproductive success.
Collapse
Affiliation(s)
- Jianqiang Wang
- Department of Botany and Plant Sciences, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, USA
| | - Thomas Eulgem
- Department of Botany and Plant Sciences, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, California, USA
| |
Collapse
|
3
|
Wang Y, Yuan S, Shao C, Zhu W, Xiao D, Zhang C, Hou X, Li Y. BcOPR3 Mediates Defense Responses to Biotrophic and Necrotrophic Pathogens in Arabidopsis and Non-heading Chinese Cabbage. PHYTOPATHOLOGY 2022; 112:2523-2537. [PMID: 35852468 DOI: 10.1094/phyto-02-22-0049-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In plants, the salicylic acid (SA) and jasmonic acid (JA) signaling pathways usually mediate the defense response to biotrophic and necrotrophic pathogens, respectively. Our previous work showed that after non-heading Chinese cabbage (NHCC) was infected with the biotrophic pathogen Hyaloperonospora parasitica, expression of the JA biosynthetic gene BcOPR3 is induced; however, its molecular mechanism remains unclear. Here, we overexpressed BcOPR3 in Arabidopsis and silenced BcOPR3 in NHCC001 plants to study the defensive role of BcOPR3 in plants against pathogen invasion. The results showed that overexpression of BcOPR3 increased the susceptibility of Arabidopsis to Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) but enhanced its resistance to Botrytis cinerea. BcOPR3-silenced NHCC001 plants with a 50% reduction in BcOPR3 expression increased their resistance to downy mildew by reducing the hyphal density and spores of H. parasitica. In addition, BcOPR3-partly silenced NHCC001 plants were also resistant to B. cinerea, which could be the result of a synergistic effect of JA and SA. These findings indicate a complicated role of BcOPR3 in the mediating defense responses to biotrophic and necrotrophic pathogens.
Collapse
Affiliation(s)
- Yuan Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Shuilin Yuan
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Cen Shao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Weitong Zhu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Dong Xiao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Changwei Zhang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Xilin Hou
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| | - Ying Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing 210095, China
| |
Collapse
|
4
|
RING-Type E3 Ubiquitin Ligases AtRDUF1 and AtRDUF2 Positively Regulate the Expression of PR1 Gene and Pattern-Triggered Immunity. Int J Mol Sci 2022; 23:ijms232314525. [PMID: 36498851 PMCID: PMC9739713 DOI: 10.3390/ijms232314525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/18/2022] [Accepted: 11/18/2022] [Indexed: 11/23/2022] Open
Abstract
The importance of E3 ubiquitin ligases from different families for plant immune signaling has been confirmed. Plant RING-type E3 ubiquitin ligases are members of the E3 ligase superfamily and have been shown to play positive or negative roles during the regulation of various steps of plant immunity. Here, we present Arabidopsis RING-type E3 ubiquitin ligases AtRDUF1 and AtRDUF2 which act as positive regulators of flg22- and SA-mediated defense signaling. Expression of AtRDUF1 and AtRDUF2 is induced by pathogen-associated molecular patterns (PAMPs) and pathogens. The atrduf1 and atrduf2 mutants displayed weakened responses when triggered by PAMPs. Immune responses, including oxidative burst, mitogen-activated protein kinase (MAPK) activity, and transcriptional activation of marker genes, were attenuated in the atrduf1 and atrduf2 mutants. The suppressed activation of PTI responses also resulted in enhanced susceptibility to bacterial pathogens. Interestingly, atrduf1 and atrduf2 mutants showed defects in SA-mediated or pathogen-mediated PR1 expression; however, avirulent Pseudomonas syringae pv. tomato DC3000-induced cell death was unaffected. Our findings suggest that AtRDUF1 and AtRDUF2 are not just PTI-positive regulators but are also involved in SA-mediated PR1 gene expression, which is important for resistance to P. syringae.
Collapse
|
5
|
Wang Y, Hu Q, Wu Z, Wang H, Han S, Jin Y, Zhou J, Zhang Z, Jiang J, Shen Y, Shi H, Yang W. HISTONE DEACETYLASE 6 represses pathogen defence responses in Arabidopsis thaliana. PLANT, CELL & ENVIRONMENT 2017; 40:2972-2986. [PMID: 28770584 DOI: 10.1111/pce.13047] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 07/23/2017] [Indexed: 05/18/2023]
Abstract
Plant defence mechanisms are suppressed in the absence of pathogen attack to prevent wasted energy and growth inhibition. However, how defence responses are repressed is not well understood. Histone deacetylase 6 (HDA6) is a negative regulator of gene expression, and its role in pathogen defence response in plants is not known. In this study, a novel allele of hda6 (designated as shi5) with spontaneous defence response was isolated from a forward genetics screening in Arabidopsis. The shi5 mutant exhibited increased resistance to hemibiotrophic bacterial pathogen Pst DC3000, constitutively activated expression of pathogen-responsive genes including PR1, PR2, etc. and increased histone acetylation levels at the promoters of most tested genes that were upregulated in shi5. In both wild type and shi5 plants, the expression and histone acetylation of these genes were upregulated by pathogen infection. HDA6 was found to bind to the promoters of these genes under both normal growth conditions and pathogen infection. Our research suggests that HDA6 is a general repressor of pathogen defence response and plays important roles in inhibiting and modulating the expression of pathogen-responsive genes in Arabidopsis.
Collapse
Affiliation(s)
- Yizhong Wang
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Qin Hu
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Zhenjiang Wu
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Hui Wang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
| | - Shiming Han
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Ye Jin
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Jin Zhou
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Zhengfeng Zhang
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| | - Jiafu Jiang
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
| | - Yun Shen
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
| | - Huazhong Shi
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX, 79409, USA
| | - Wannian Yang
- School of Life Sciences, Central China Normal University, Wuhan, 43009, Hubei, P.R. China
| |
Collapse
|
6
|
Olukolu BA, Bian Y, De Vries B, Tracy WF, Wisser RJ, Holland JB, Balint-Kurti PJ. The Genetics of Leaf Flecking in Maize and Its Relationship to Plant Defense and Disease Resistance. PLANT PHYSIOLOGY 2016; 172:1787-1803. [PMID: 27670817 PMCID: PMC5100796 DOI: 10.1104/pp.15.01870] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 09/22/2016] [Indexed: 05/20/2023]
Abstract
Physiological leaf spotting, or flecking, is a mild-lesion phenotype observed on the leaves of several commonly used maize (Zea mays) inbred lines and has been anecdotally linked to enhanced broad-spectrum disease resistance. Flecking was assessed in the maize nested association mapping (NAM) population, comprising 4,998 recombinant inbred lines from 25 biparental families, and in an association population, comprising 279 diverse maize inbreds. Joint family linkage analysis was conducted with 7,386 markers in the NAM population. Genome-wide association tests were performed with 26.5 million single-nucleotide polymorphisms (SNPs) in the NAM population and with 246,497 SNPs in the association population, resulting in the identification of 18 and three loci associated with variation in flecking, respectively. Many of the candidate genes colocalizing with associated SNPs are similar to genes that function in plant defense response via cell wall modification, salicylic acid- and jasmonic acid-dependent pathways, redox homeostasis, stress response, and vesicle trafficking/remodeling. Significant positive correlations were found between increased flecking, stronger defense response, increased disease resistance, and increased pest resistance. A nonlinear relationship with total kernel weight also was observed whereby lines with relatively high levels of flecking had, on average, lower total kernel weight. We present evidence suggesting that mild flecking could be used as a selection criterion for breeding programs trying to incorporate broad-spectrum disease resistance.
Collapse
Affiliation(s)
- Bode A Olukolu
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695-7616 (B.A.O., P.J.B.-K.)
- Department of Crop Science, North Carolina State University, Raleigh, North Carolina 27695-7620 (B.A.O., Y.B., J.B.H.)
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706 (B.D.V., W.F.T.)
- Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716 (R.J.W.); and
- United States Department of Agriculture-Agricultural Research Service Plant Science Research Unit, Raleigh, North Carolina 27695 (J.B.H., P.J.B.-K.)
| | - Yang Bian
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695-7616 (B.A.O., P.J.B.-K.)
- Department of Crop Science, North Carolina State University, Raleigh, North Carolina 27695-7620 (B.A.O., Y.B., J.B.H.)
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706 (B.D.V., W.F.T.)
- Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716 (R.J.W.); and
- United States Department of Agriculture-Agricultural Research Service Plant Science Research Unit, Raleigh, North Carolina 27695 (J.B.H., P.J.B.-K.)
| | - Brian De Vries
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695-7616 (B.A.O., P.J.B.-K.)
- Department of Crop Science, North Carolina State University, Raleigh, North Carolina 27695-7620 (B.A.O., Y.B., J.B.H.)
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706 (B.D.V., W.F.T.)
- Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716 (R.J.W.); and
- United States Department of Agriculture-Agricultural Research Service Plant Science Research Unit, Raleigh, North Carolina 27695 (J.B.H., P.J.B.-K.)
| | - William F Tracy
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695-7616 (B.A.O., P.J.B.-K.)
- Department of Crop Science, North Carolina State University, Raleigh, North Carolina 27695-7620 (B.A.O., Y.B., J.B.H.)
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706 (B.D.V., W.F.T.)
- Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716 (R.J.W.); and
- United States Department of Agriculture-Agricultural Research Service Plant Science Research Unit, Raleigh, North Carolina 27695 (J.B.H., P.J.B.-K.)
| | - Randall J Wisser
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695-7616 (B.A.O., P.J.B.-K.)
- Department of Crop Science, North Carolina State University, Raleigh, North Carolina 27695-7620 (B.A.O., Y.B., J.B.H.)
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706 (B.D.V., W.F.T.)
- Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716 (R.J.W.); and
- United States Department of Agriculture-Agricultural Research Service Plant Science Research Unit, Raleigh, North Carolina 27695 (J.B.H., P.J.B.-K.)
| | - James B Holland
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695-7616 (B.A.O., P.J.B.-K.)
- Department of Crop Science, North Carolina State University, Raleigh, North Carolina 27695-7620 (B.A.O., Y.B., J.B.H.)
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706 (B.D.V., W.F.T.)
- Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716 (R.J.W.); and
- United States Department of Agriculture-Agricultural Research Service Plant Science Research Unit, Raleigh, North Carolina 27695 (J.B.H., P.J.B.-K.)
| | - Peter J Balint-Kurti
- Department of Plant Pathology, North Carolina State University, Raleigh, North Carolina 27695-7616 (B.A.O., P.J.B.-K.);
- Department of Crop Science, North Carolina State University, Raleigh, North Carolina 27695-7620 (B.A.O., Y.B., J.B.H.);
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706 (B.D.V., W.F.T.);
- Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware 19716 (R.J.W.); and
- United States Department of Agriculture-Agricultural Research Service Plant Science Research Unit, Raleigh, North Carolina 27695 (J.B.H., P.J.B.-K.)
| |
Collapse
|
7
|
Bektas Y, Rodriguez-Salus M, Schroeder M, Gomez A, Kaloshian I, Eulgem T. The Synthetic Elicitor DPMP (2,4-dichloro-6-{(E)-[(3-methoxyphenyl)imino]methyl}phenol) Triggers Strong Immunity in Arabidopsis thaliana and Tomato. Sci Rep 2016; 6:29554. [PMID: 27412821 PMCID: PMC4944173 DOI: 10.1038/srep29554] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 06/17/2016] [Indexed: 11/30/2022] Open
Abstract
Synthetic elicitors are drug-like compounds that are structurally distinct from natural defense elicitors. They can protect plants from diseases by activating host immune responses and can serve as tools for the dissection of the plant immune system as well as leads for the development of environmentally-safe pesticide alternatives. By high-throughput screening, we previously identified 114 synthetic elicitors that activate expression of the pathogen-responsive CaBP22−333::GUS reporter gene in Arabidopsis thaliana (Arabidopsis), 33 of which are [(phenylimino)methyl]phenol (PMP) derivatives or PMP-related compounds. Here we report on the characterization of one of these compounds, 2,4-dichloro-6-{(E)-[(3-methoxyphenyl)imino]methyl}phenol (DPMP). DPMP strongly triggers disease resistance of Arabidopsis against bacterial and oomycete pathogens. By mRNA-seq analysis we found transcriptional profiles triggered by DPMP to resemble typical defense-related responses.
Collapse
Affiliation(s)
- Yasemin Bektas
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California at Riverside, CA 92521, USA.,Department of Botany and Plant Sciences, University of California at Riverside, CA 92521, USA
| | - Melinda Rodriguez-Salus
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California at Riverside, CA 92521, USA.,Department of Botany and Plant Sciences, University of California at Riverside, CA 92521, USA.,ChemGen Intergrative Graduate Education and Research Traineeship program, program, University of California at Riverside, CA 92521, USA
| | - Mercedes Schroeder
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California at Riverside, CA 92521, USA.,Department of Botany and Plant Sciences, University of California at Riverside, CA 92521, USA.,ChemGen Intergrative Graduate Education and Research Traineeship program, program, University of California at Riverside, CA 92521, USA
| | - Adilene Gomez
- Department of Botany and Plant Sciences, University of California at Riverside, CA 92521, USA
| | - Isgouhi Kaloshian
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California at Riverside, CA 92521, USA.,Department of Nematology, University of California at Riverside, CA 92521, USA
| | - Thomas Eulgem
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California at Riverside, CA 92521, USA.,Department of Botany and Plant Sciences, University of California at Riverside, CA 92521, USA.,ChemGen Intergrative Graduate Education and Research Traineeship program, program, University of California at Riverside, CA 92521, USA
| |
Collapse
|
8
|
Krizek BA, Bequette CJ, Xu K, Blakley IC, Fu ZQ, Stratmann JW, Loraine AE. RNA-Seq Links the Transcription Factors AINTEGUMENTA and AINTEGUMENTA-LIKE6 to Cell Wall Remodeling and Plant Defense Pathways. PLANT PHYSIOLOGY 2016; 171:2069-84. [PMID: 27208279 PMCID: PMC4936541 DOI: 10.1104/pp.15.01625] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 05/18/2016] [Indexed: 05/18/2023]
Abstract
AINTEGUMENTA (ANT) and AINTEGUMENTA-LIKE6 (AIL6) are two related transcription factors in Arabidopsis (Arabidopsis thaliana) that have partially overlapping roles in several aspects of flower development, including floral organ initiation, identity specification, growth, and patterning. To better understand the biological processes regulated by these two transcription factors, we performed RNA sequencing (RNA-Seq) on ant ail6 double mutants. We identified thousands of genes that are differentially expressed in the double mutant compared with the wild type. Analyses of these genes suggest that ANT and AIL6 regulate floral organ initiation and growth through modifications to the cell wall polysaccharide pectin. We found reduced levels of demethylesterified homogalacturonan and altered patterns of auxin accumulation in early stages of ant ail6 flower development. The RNA-Seq experiment also revealed cross-regulation of AIL gene expression at the transcriptional level. The presence of a number of overrepresented Gene Ontology terms related to plant defense in the set of genes differentially expressed in ant ail6 suggest that ANT and AIL6 also regulate plant defense pathways. Furthermore, we found that ant ail6 plants have elevated levels of two defense hormones: salicylic acid and jasmonic acid, and show increased resistance to the bacterial pathogen Pseudomonas syringae These results suggest that ANT and AIL6 regulate biological pathways that are critical for both development and defense.
Collapse
Affiliation(s)
- Beth A Krizek
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina (B.A.K., C.J.B., K.X., Z.Q.F., J.W.S.); andDepartment of Bioinformatics and Genomics, University of North Carolina, Charlotte, North Carolina (I.C.B., A.E.L.)
| | - Carlton J Bequette
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina (B.A.K., C.J.B., K.X., Z.Q.F., J.W.S.); andDepartment of Bioinformatics and Genomics, University of North Carolina, Charlotte, North Carolina (I.C.B., A.E.L.)
| | - Kaimei Xu
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina (B.A.K., C.J.B., K.X., Z.Q.F., J.W.S.); andDepartment of Bioinformatics and Genomics, University of North Carolina, Charlotte, North Carolina (I.C.B., A.E.L.)
| | - Ivory C Blakley
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina (B.A.K., C.J.B., K.X., Z.Q.F., J.W.S.); andDepartment of Bioinformatics and Genomics, University of North Carolina, Charlotte, North Carolina (I.C.B., A.E.L.)
| | - Zheng Qing Fu
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina (B.A.K., C.J.B., K.X., Z.Q.F., J.W.S.); andDepartment of Bioinformatics and Genomics, University of North Carolina, Charlotte, North Carolina (I.C.B., A.E.L.)
| | - Johannes W Stratmann
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina (B.A.K., C.J.B., K.X., Z.Q.F., J.W.S.); andDepartment of Bioinformatics and Genomics, University of North Carolina, Charlotte, North Carolina (I.C.B., A.E.L.)
| | - Ann E Loraine
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina (B.A.K., C.J.B., K.X., Z.Q.F., J.W.S.); andDepartment of Bioinformatics and Genomics, University of North Carolina, Charlotte, North Carolina (I.C.B., A.E.L.)
| |
Collapse
|
9
|
Yi SY, Min SR, Kwon SY. NPR1 is Instrumental in Priming for the Enhanced flg22-induced MPK3 and MPK6 Activation. THE PLANT PATHOLOGY JOURNAL 2015; 31:192-4. [PMID: 26060439 PMCID: PMC4454001 DOI: 10.5423/ppj.nt.10.2014.0112] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 03/05/2015] [Accepted: 03/15/2015] [Indexed: 05/04/2023]
Abstract
Pathogen-associated molecular patterns (PAMPs) activate mitogen-activated protein kinases (MAPKs), essential components of plant defense signaling. Salicylic acid (SA) is also central to plant resistance responses, but its specific role in regulation of MAPK activation is not completely defined. We have investigated the role of SA in PAMP-triggered MAPKs pathways in Arabidopsis SA-related mutants, specifically in the flg22-triggered activation of MPK3 and MPK6. cim6, sid2, and npr1 mutants exhibited wild-type-like flg22-triggered MAPKs activation, suggesting that impairment of SA signaling has no effect on the flg22-triggered MAPKs activation. Pretreatment with low concentrations of SA enhanced flg22-induced MPK3 and MPK6 activation in all seedlings except npr1, indicating that NPR1 is involved in SA-mediated priming that enhanced flg22-induced MAPKs activation.
Collapse
Affiliation(s)
- So Young Yi
- Co-corresponding authors. So Young Yi, Phone) +82-42-860-4433, FAX) +82-42-860-4608, E-mail) . Suk-Yoon Kwon, Phone) +82-42-860-4340, FAX) +82-42-860-4349, E-mail)
| | | | - Suk-Yoon Kwon
- Co-corresponding authors. So Young Yi, Phone) +82-42-860-4433, FAX) +82-42-860-4608, E-mail) . Suk-Yoon Kwon, Phone) +82-42-860-4340, FAX) +82-42-860-4349, E-mail)
| |
Collapse
|
10
|
Sade D, Sade N, Shriki O, Lerner S, Gebremedhin A, Karavani A, Brotman Y, Osorio S, Fernie AR, Willmitzer L, Czosnek H, Moshelion M. Water Balance, Hormone Homeostasis, and Sugar Signaling Are All Involved in Tomato Resistance to Tomato Yellow Leaf Curl Virus. PLANT PHYSIOLOGY 2014; 165:1684-1697. [PMID: 24989233 PMCID: PMC4119048 DOI: 10.1104/pp.114.243402] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 07/01/2014] [Indexed: 05/22/2023]
Abstract
Vacuolar water movement is largely controlled by membrane channels called tonoplast-intrinsic aquaporins (TIP-AQPs). Some TIP-AQP genes, such as TIP2;2 and TIP1;1, are up-regulated upon exposure to biotic stress. Moreover, TIP1;1 transcript levels are higher in leaves of a tomato (Solanum lycopersicum) line resistant to Tomato yellow leaf curl virus (TYLCV) than in those of a susceptible line with a similar genetic background. Virus-induced silencing of TIP1;1 in the tomato resistant line and the use of an Arabidopsis (Arabidopsis thaliana) tip1;1 null mutant showed that resistance to TYLCV is severely compromised in the absence of TIP1:1. Constitutive expression of tomato TIP2;2 in transgenic TYLCV-susceptible tomato and Arabidopsis plants was correlated with increased TYLCV resistance, increased transpiration, decreased abscisic acid levels, and increased salicylic acid levels at the early stages of infection. We propose that TIP-AQPs affect the induction of leaf abscisic acid, which leads to increased levels of transpiration and gas exchange, as well as better salicylic acid signaling.
Collapse
Affiliation(s)
- Dagan Sade
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel (D.S., N.S., O.S., S.L., A.G., A.K., H.C., M.M.); andMax Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (Y.B., S.O., A.R.F., L.W.)
| | - Nir Sade
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel (D.S., N.S., O.S., S.L., A.G., A.K., H.C., M.M.); andMax Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (Y.B., S.O., A.R.F., L.W.)
| | - Oz Shriki
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel (D.S., N.S., O.S., S.L., A.G., A.K., H.C., M.M.); andMax Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (Y.B., S.O., A.R.F., L.W.)
| | - Stephen Lerner
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel (D.S., N.S., O.S., S.L., A.G., A.K., H.C., M.M.); andMax Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (Y.B., S.O., A.R.F., L.W.)
| | - Alem Gebremedhin
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel (D.S., N.S., O.S., S.L., A.G., A.K., H.C., M.M.); andMax Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (Y.B., S.O., A.R.F., L.W.)
| | - Asaf Karavani
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel (D.S., N.S., O.S., S.L., A.G., A.K., H.C., M.M.); andMax Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (Y.B., S.O., A.R.F., L.W.)
| | - Yariv Brotman
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel (D.S., N.S., O.S., S.L., A.G., A.K., H.C., M.M.); andMax Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (Y.B., S.O., A.R.F., L.W.)
| | - Sonia Osorio
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel (D.S., N.S., O.S., S.L., A.G., A.K., H.C., M.M.); andMax Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (Y.B., S.O., A.R.F., L.W.)
| | - Alisdair R Fernie
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel (D.S., N.S., O.S., S.L., A.G., A.K., H.C., M.M.); andMax Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (Y.B., S.O., A.R.F., L.W.)
| | - Lothar Willmitzer
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel (D.S., N.S., O.S., S.L., A.G., A.K., H.C., M.M.); andMax Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (Y.B., S.O., A.R.F., L.W.)
| | - Henryk Czosnek
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel (D.S., N.S., O.S., S.L., A.G., A.K., H.C., M.M.); andMax Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (Y.B., S.O., A.R.F., L.W.)
| | - Menachem Moshelion
- Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel (D.S., N.S., O.S., S.L., A.G., A.K., H.C., M.M.); andMax Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany (Y.B., S.O., A.R.F., L.W.)
| |
Collapse
|
11
|
Lai Y, Dang F, Lin J, Yu L, Lin J, Lei Y, Chen C, Liu Z, Qiu A, Mou S, Guan D, Wu Y, He S. Overexpression of a pepper CaERF5 gene in tobacco plants enhances resistance to Ralstonia solanacearum infection. FUNCTIONAL PLANT BIOLOGY : FPB 2014; 41:758-767. [PMID: 32481030 DOI: 10.1071/fp13305] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2013] [Accepted: 01/13/2014] [Indexed: 05/11/2023]
Abstract
ETHYLENE RESPONSE FACTORs (ERF) transcription factors (TFs) constitute a large transcriptional regulator family belonging to the AP2/ERF superfamily and are implicated in a range of biological processes. However, the specific roles of individual ERF family members in biotic or abiotic stress responses and the underlying molecular mechanism still need to be elucidated. In the present study, a cDNA encoding a member of ethylene response factor (ERF) transcription factor, CaERF5, was isolated from pepper. Sequence analysis showed that CaERF5 contains a typical 59 amino acid AP2/ERF DNA-binding domain, two highly conserved amino acid residues (14th alanine (A) and 19th aspartic acid (D)), a putative nuclear localisation signal (NLS), a CMIX-2 motif in the N-terminal region and two putative MAP kinase phosphorylation site CMIX-5 and CMIX-6 motifs. It belongs to group IXb of the ERF subfamily. A CaERF5-green fluorescence protein (GFP) fusion transiently expressed in onion epidermal cells localised to the nucleus. CaERF5 transcripts were induced by Ralstonia solanacearum infection, salicylic acid (SA), methyl jasmonate (MeJA) and ethephon (ETH) treatments. Constitutive expression of the CaERF5 gene in tobacco plants upregulated transcript levels of a set of defence- related genes and enhanced resistance to R. solanacearum infection. Our results suggest that CaERF5 acts as a positive regulator in plant resistance to R. solanacearum infection and show that overexpression of this transcription factor can be used as a tool to enhance disease resistance in crop species.
Collapse
Affiliation(s)
- Yan Lai
- Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Fengfeng Dang
- Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Jing Lin
- Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Lu Yu
- Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Jinhui Lin
- Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Yufen Lei
- Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Chengcong Chen
- Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Zhiqin Liu
- Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Ailian Qiu
- Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Shaoliang Mou
- Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Deyi Guan
- Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Yang Wu
- Jinggangshan University, Jian, Jiangxi 343009, China
| | - Shuilin He
- Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| |
Collapse
|
12
|
Mitochondrial AtPAM16 is required for plant survival and the negative regulation of plant immunity. Nat Commun 2014; 4:2558. [PMID: 24153405 DOI: 10.1038/ncomms3558] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/04/2013] [Indexed: 12/21/2022] Open
Abstract
Proteins containing nucleotide-binding and leucine-rich repeat domains (NB-LRRs) serve as immune receptors in plants and animals. Negative regulation of immunity mediated by NB-LRR proteins is crucial, as their overactivation often leads to autoimmunity. Here we describe a new mutant, snc1-enhancing (muse) forward genetic screen, targeting unknown negative regulators of NB-LRR-mediated resistance in Arabidopsis. From the screen, we identify MUSE5, which is renamed as AtPAM16 because it encodes the ortholog of yeast PAM16, part of the mitochondrial inner membrane protein import motor. Consistently, AtPAM16-GFP localizes to the mitochondrial inner membrane. AtPAM16L is a paralog of AtPAM16. Double mutant Atpam16-1 Atpam16l is lethal, indicating that AtPAM16 function is essential. Single mutant Atpam16 plants exhibit a smaller size and enhanced resistance against virulent pathogens. They also display elevated reactive oxygen species (ROS) accumulation. Therefore, AtPAM16 seems to be involved in importing a negative regulator of plant immunity into mitochondria, thus protecting plants from over-accumulation of ROS and preventing autoimmunity.
Collapse
|
13
|
Xu E, Brosché M. Salicylic acid signaling inhibits apoplastic reactive oxygen species signaling. BMC PLANT BIOLOGY 2014; 14:155. [PMID: 24898702 PMCID: PMC4057906 DOI: 10.1186/1471-2229-14-155] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 05/29/2014] [Indexed: 05/03/2023]
Abstract
BACKGROUND Reactive oxygen species (ROS) are used by plants as signaling molecules during stress and development. Given the amount of possible challenges a plant face from their environment, plants need to activate and prioritize between potentially conflicting defense signaling pathways. Until recently, most studies on signal interactions have focused on phytohormone interaction, such as the antagonistic relationship between salicylic acid (SA)-jasmonic acid and cytokinin-auxin. RESULTS In this study, we report an antagonistic interaction between SA signaling and apoplastic ROS signaling. Treatment with ozone (O3) leads to a ROS burst in the apoplast and induces extensive changes in gene expression and elevation of defense hormones. However, Arabidopsis thaliana dnd1 (defense no death1) exhibited an attenuated response to O3. In addition, the dnd1 mutant displayed constitutive expression of defense genes and spontaneous cell death. To determine the exact process which blocks the apoplastic ROS signaling, double and triple mutants involved in various signaling pathway were generated in dnd1 background. Simultaneous elimination of SA-dependent and SA-independent signaling components from dnd1 restored its responsiveness to O3. Conversely, pre-treatment of plants with SA or using mutants that constitutively activate SA signaling led to an attenuation of changes in gene expression elicited by O3. CONCLUSIONS Based upon these findings, we conclude that plants are able to prioritize the response between ROS and SA via an antagonistic action of SA and SA signaling on apoplastic ROS signaling.
Collapse
Affiliation(s)
- Enjun Xu
- Division of Plant Biology, Department of Biosciences, University of Helsinki, P.O. Box 65 (Viikinkaari 1), FI-00014 Helsinki, Finland
| | - Mikael Brosché
- Division of Plant Biology, Department of Biosciences, University of Helsinki, P.O. Box 65 (Viikinkaari 1), FI-00014 Helsinki, Finland
- Institute of Technology, University of Tartu, Nooruse 1, Tartu 50411, Estonia
| |
Collapse
|
14
|
Ghosh Dasgupta M, George BS, Bhatia A, Sidhu OP. Characterization of Withania somnifera leaf transcriptome and expression analysis of pathogenesis-related genes during salicylic acid signaling. PLoS One 2014; 9:e94803. [PMID: 24739900 PMCID: PMC3989240 DOI: 10.1371/journal.pone.0094803] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 03/19/2014] [Indexed: 12/20/2022] Open
Abstract
Withania somnifera (L.) Dunal is a valued medicinal plant with pharmaceutical applications. The present study was undertaken to analyze the salicylic acid induced leaf transcriptome of W. somnifera. A total of 45.6 million reads were generated and the de novo assembly yielded 73,523 transcript contig with average transcript contig length of 1620 bp. A total of 71,062 transcripts were annotated and 53,424 of them were assigned GO terms. Mapping of transcript contigs to biological pathways revealed presence of 182 pathways. Seventeen genes representing 12 pathogenesis-related (PR) families were mined from the transcriptome data and their pattern of expression post 17 and 36 hours of salicylic acid treatment was documented. The analysis revealed significant up-regulation of all families of PR genes by 36 hours post treatment except WsPR10. The relative fold expression of transcripts ranged from 1 fold to 6,532 fold. The two families of peroxidases including the lignin-forming anionic peroxidase (WsL-PRX) and suberization-associated anionic peroxidase (WsS-PRX) recorded maximum expression of 377 fold and 6532 fold respectively, while the expression of WsPR10 was down-regulated by 14 fold. Additionally, the most stable reference gene for normalization of qRT-PCR data was also identified. The effect of SA on the accumulation of major secondary metabolites of W. somnifera including withanoside V, withaferin A and withanolide A was also analyzed and an increase in content of all the three metabolites were detected. This is the first report on expression patterns of PR genes during salicylic acid signaling in W. somnifera.
Collapse
Affiliation(s)
- Modhumita Ghosh Dasgupta
- Division of Plant Biotechnology, Institute of Forest Genetics and Tree Breeding, R.S. Puram, Coimbatore, Tamil Nadu, India
- * E-mail:
| | - Blessan Santhosh George
- Division of Plant Biotechnology, Institute of Forest Genetics and Tree Breeding, R.S. Puram, Coimbatore, Tamil Nadu, India
| | - Anil Bhatia
- CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, Uttar Pradesh, India
| | - Om Prakash Sidhu
- CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, Uttar Pradesh, India
| |
Collapse
|
15
|
The activated SA and JA signaling pathways have an influence on flg22-triggered oxidative burst and callose deposition. PLoS One 2014; 9:e88951. [PMID: 24586453 PMCID: PMC3934882 DOI: 10.1371/journal.pone.0088951] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 01/15/2014] [Indexed: 12/13/2022] Open
Abstract
The first line of defense in plants against pathogens is induced by the recognition of microbe-associated molecular patterns (MAMP). Perception of bacterial flagellin (flg22) by the pattern recognition receptor flagellin-sensing 2 (FLS2) is the best characterized MAMP response, although the underlying molecular mechanisms are not fully understood. Here we studied the relationship between salicylic acid (SA) or jasmonic acid (JA) signaling and FLS2-mediated signaling by monitoring flg22-triggered responses in known SA or JA related mutants of Arabidopsis thaliana (L.) Heynh. The sid2 mutant, impaired in SA biosynthesis, had less basal FLS2 mRNA accumulation than the wild type, which correlated with suppression of early flg22 responses such as ROS production and induction of marker genes, WRKY29 and FRK1. The JA-signaling mutants, jar1 and coi1, exhibited an enhanced flg22-triggered oxidative burst and more callose accumulation than the wild type, and pretreatment with SA or coronatine (COR), a structural mimic of JA-isoleucine, altered these flg22-induced responses. Nonexpressor of pathogenesis-related genes 1 (NPR1) acted downstream of SID2 and required SA-dependent priming for the enhanced flg22-triggered oxidative burst and callose deposition. Activation of JA signaling by COR pretreatment suppressed the flg22-triggered oxidative burst and callose accumulation in a coronatine insensitive 1 (COI1) dependent manner. COR had a negative effect on flg22 responses but only the flg22-triggered oxidative burst depended on SA-JA/COR signaling antagonism. Thus the activated SA and JA signaling pathways have an influence on flg22-triggered oxidative burst and callose deposition. These results may explain how SA and JA signaling are cross talked for regulation of flg22-triggered responses.
Collapse
|
16
|
Abstract
Salicylic acid (SA) has a central role in activating plant resistance to pathogens. SA levels increase in plant tissue following pathogen infection and exogenous SA enhances resistance to a broad range of pathogens. To study the relevance of the SA signaling in the flg22 response, we investigated the responses of SA-related mutants to flg22, a 22-amino acid peptide of the flagellin bacterial protein. We identified SA as an important component of the flg22-triggered oxidative burst, a very early event after flg22 detection, and gene induction, an early event. SA acted partially by enhancing accumulation of FLS2 mRNA. We also provide new evidence that NPR1 play a role in SA-induced priming event that enhances the flg22-triggered oxidative burst, which is correlated with enhancement of the flg22-induced callose deposition. Based on these observations, we conclude that SA signaling is required for early as well as late flg22 responses.
Collapse
Affiliation(s)
- So Young Yi
- Plant Systems Engineering Research Center; Korea Research Institute Bioscience and Biotechnology (KRIBB); Yuseong-gu, Daejeon; Republic of Korea
- Correspondence to: So Young Yi; ; Suk-Yoon Kwon;
| | - Suk-Yoon Kwon
- Plant Systems Engineering Research Center; Korea Research Institute Bioscience and Biotechnology (KRIBB); Yuseong-gu, Daejeon; Republic of Korea
- Correspondence to: So Young Yi; ; Suk-Yoon Kwon;
| |
Collapse
|
17
|
Zhang Z, van Esse HP, van Damme M, Fradin EF, Liu CM, Thomma BPHJ. Ve1-mediated resistance against Verticillium does not involve a hypersensitive response in Arabidopsis. MOLECULAR PLANT PATHOLOGY 2013; 14:719-27. [PMID: 23710897 PMCID: PMC6638679 DOI: 10.1111/mpp.12042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The recognition of pathogen effectors by plant immune receptors leads to the activation of immune responses that often include a hypersensitive response (HR): rapid and localized host cell death surrounding the site of attempted pathogen ingress. We have demonstrated previously that the recognition of the Verticillium dahliae effector protein Ave1 by the tomato immune receptor Ve1 triggers an HR in tomato and tobacco. Furthermore, we have demonstrated that tomato Ve1 provides Verticillium resistance in Arabidopsis upon Ave1 recognition. In this study, we investigated whether the co-expression of Ve1 and Ave1 in Arabidopsis results in an HR, which could facilitate a forward genetics screen. Surprisingly, we found that the co-expression of Ve1 and Ave1 does not induce an HR in Arabidopsis. These results suggest that an HR may occur as a consequence of Ve1/Ave1-induced immune signalling in tomato and tobacco, but is not absolutely required for Verticillium resistance.
Collapse
Affiliation(s)
- Zhao Zhang
- Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, the Netherlands
| | | | | | | | | | | |
Collapse
|
18
|
Kim HS, Park HC, Kim KE, Jung MS, Han HJ, Kim SH, Kwon YS, Bahk S, An J, Bae DW, Yun DJ, Kwak SS, Chung WS. A NAC transcription factor and SNI1 cooperatively suppress basal pathogen resistance in Arabidopsis thaliana. Nucleic Acids Res 2012; 40:9182-92. [PMID: 22826500 PMCID: PMC3467076 DOI: 10.1093/nar/gks683] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Transcriptional repression of pathogen defense-related genes is essential for plant growth and development. Several proteins are known to be involved in the transcriptional regulation of plant defense responses. However, mechanisms by which expression of defense-related genes are regulated by repressor proteins are poorly characterized. Here, we describe the in planta function of CBNAC, a calmodulin-regulated NAC transcriptional repressor in Arabidopsis. A T-DNA insertional mutant (cbnac1) displayed enhanced resistance to a virulent strain of the bacterial pathogen Pseudomonas syringae DC3000 (PstDC3000), whereas resistance was reduced in transgenic CBNAC overexpression lines. The observed changes in disease resistance were correlated with alterations in pathogenesis-related protein 1 (PR1) gene expression. CBNAC bound directly to the PR1 promoter. SNI1 (suppressor of nonexpressor of PR genes1, inducible 1) was identified as a CBNAC-binding protein. Basal resistance to PstDC3000 and derepression of PR1 expression was greater in the cbnac1 sni1 double mutant than in either cbnac1 or sni1 mutants. SNI1 enhanced binding of CBNAC to its cognate PR1 promoter element. CBNAC and SNI1 are hypothesized to work as repressor proteins in the cooperative suppression of plant basal defense.
Collapse
Affiliation(s)
- Ho Soo Kim
- Division of Applied Life Science (BK21 Program), Gyeongsang National University, Jinju 660-701, Korea
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Ono S, Kusama M, Ogura R, Hiratsuka K. Evaluation of the use of the tobacco PR-1a promoter to monitor defense gene expression by the luciferase bioluminescence reporter system. Biosci Biotechnol Biochem 2011; 75:1796-800. [PMID: 21897029 DOI: 10.1271/bbb.110326] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Because of their marked responsiveness to induction signals, genes encoding pathogenesis-related proteins are used as markers to monitor defense gene expression in plants. To develop a non-invasive bioluminescence reporter assay system, we tested acidic PR-1 gene promoters from tobacco and Arabidopsis. These two promoters share common regulatory elements and are believed to show similar responsiveness to various stimuli but the results of transient expression assays by microprojectile bombardment of various plant cells and npr1 mutant Arabidopsis suggest that the tobacco PR-1a promoter is superior to its Arabidopsis counterpart in terms of responsiveness to salicylic acid treatment. Transgenic Arabidopsis seedlings harboring the tobacco PR-1a promoter fused to firefly luciferase showed marked induction in response to treatment with chemicals that induce defense gene expression in plants. These results suggest that the tobacco PR-1a promoter is applicable in monitoring defense-gene expression in various plant species.
Collapse
Affiliation(s)
- Sachiko Ono
- Graduate School of Environment and Information Sciences, Yokohama National University
| | | | | | | |
Collapse
|
20
|
Sharon M, Freeman S, Sneh B. Assessment of resistance pathways induced in Arabidopsis thaliana by hypovirulent Rhizoctonia spp. isolates. PHYTOPATHOLOGY 2011; 101:828-38. [PMID: 21385012 DOI: 10.1094/phyto-09-10-0247] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Certain hypovirulent Rhizoctonia isolates effectively protect plants against well-known important pathogens among Rhizoctonia isolates as well as against other pathogens. The modes of action involved in this protection include resistance induced in plants by colonization with hypovirulent Rhizoctonia isolates. The qualifications of hypovirulent isolates (efficient protection, rapid growth, effective colonization of the plants, and easy application in the field) provide a significant potential for the development of a commercial microbial preparation for application as biological control agents. Understanding of the modes of action involved in protection is important for improving the various aspects of development and application of such preparations. The hypothesis of the present study is that resistance pathways such as systemic acquired resistance (SAR), induced systemic resistance (ISR), and phytoalexins are induced in plants colonized by the protective hypovirulent Rhizoctonia isolates and are involved in the protection of these plants against pathogenic Rhizoctonia. Changes in protection levels of Arabidopsis thaliana mutants defective in defense-related genes (npr1-1, npr1-2, ndr1-1, npr1-2/ndr1-1, cim6, wrky70.1, snc1, and pbs3-1) and colonized with the hypovirulent Rhizoctonia isolates compared with that of the wild type (wt) plants colonized with the same isolates confirmed the involvement of induced resistance in the protection of the plants against pathogenic Rhizoctonia spp., although protection levels of mutants constantly expressing SAR genes (snc1 and cim6) were lower than that of wt plants. Plant colonization by hypovirulent Rhizoctonia isolates induced elevated expression levels of the following genes: PR5 (SAR), PDF1.2, LOX2, LOX1, CORI3 (ISR), and PAD3 (phytoalexin production), which indicated that all of these pathways were induced in the hypovirulent-colonized plants. When SAR or ISR were induced separately in plants after application of the chemical inducers Bion and methyl jasmonate, respectively, only ISR activation resulted in a higher protection level against the pathogen, although the protection was minor. In conclusion, plant colonization with the protective hypovirulent Rhizoctonia isolates significantly induced genes involved in the SAR, ISR, and phytoalexin production pathways. In the studied system, SAR probably did not play a major role in the mode of protection against pathogenic Rhizoctonia spp.; however, it may play a more significant role in protection against other pathogens.
Collapse
Affiliation(s)
- Michal Sharon
- Department of Molecular Biology and Ecology of Plants, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel
| | | | | |
Collapse
|
21
|
Canet JV, Dobón A, Roig A, Tornero P. Structure-function analysis of npr1 alleles in Arabidopsis reveals a role for its paralogs in the perception of salicylic acid. PLANT, CELL & ENVIRONMENT 2010; 33:1911-22. [PMID: 20561252 DOI: 10.1111/j.1365-3040.2010.02194.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Salicylic acid (SA) is necessary for plant defence against some pathogens, whereas NPR1 is necessary for SA perception. Plant defence can be induced to an extreme by several applications of benzothiadiazole (BTH), an analogue of SA. Thus, plants that do not perceive BTH grow unaffected, whereas wild-type plants grow stunted. This feature allows us to screen for mutants in Arabidopsis thaliana that show insensitivity to BTH in a high-throughput fashion. Most of the mutants are npr1 alleles, with similar phenotypes in plant weight and pathogen growth. The mutations are clustered in the carboxyl-terminal part of the protein, and no obvious null alleles were recovered. These facts have prompted a search for knockouts in the NPR1 gene. Two of these KO alleles identified are null and have an intermediate phenotype. All the evidence presented lead us to propose a redundancy in SA perception, with the paralogs of NPR1 taking part in this signalling. We show that the mutations recovered in the screening genetically interact with the paralogs preventing their function in SA signalling.
Collapse
Affiliation(s)
- Juan Vicente Canet
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV)-Consejo Superior de Investigaciones Científicas (CSIC), Ciudad Politécnica de la Innovación (CPI), Ed. 8E C/ Ingeniero Fausto Elio s/n, 46022 Valencia, Spain
| | | | | | | |
Collapse
|
22
|
Tsuchiya T, Eulgem T. The Arabidopsis defense component EDM2 affects the floral transition in an FLC-dependent manner. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2010; 62:518-28. [PMID: 20149132 DOI: 10.1111/j.1365-313x.2010.04169.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Arabidopsis thaliana EDM2 was previously shown to be specifically required for disease resistance mediated by the R protein RPP7. Here we provide additional data showing that the role of EDM2 in plant immunity is limited and does not include a function in basal defense. In addition, we found that EDM2 has a promoting effect on the floral transition. We further found that the protein kinase WNK8 physically interacts with EDM2 in the nucleus. Unlike EDM2, which serves as a substrate of this kinase, WNK8 appears not to be required for RPP7-mediated defense. As reported previously, however, WNK8 does affect flowering time. Epistasis analyses suggested that EDM2 acts upstream of the floral repressor FLC (AT5G10140) and downstream of WNK8 (AT5G41990) in a regulatory module that resembles the autonomous floral promotion pathway, comprising a set of mechanisms that are known to affect the floral transition by regulating FLC transcript levels.
Collapse
Affiliation(s)
- Tokuji Tsuchiya
- Center for Plant Cell Biology, Institute for Integrative Genome Biology, Department of Botany and Plant Sciences, University of California at Riverside, Riverside, CA 92521, USA
| | | |
Collapse
|
23
|
Ashrafi H, Kinkade M, Foolad MR. A new genetic linkage map of tomato based on a Solanum lycopersicum x S. pimpinellifolium RIL population displaying locations of candidate pathogen response genes. Genome 2010; 52:935-56. [PMID: 19935918 DOI: 10.1139/g09-065] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The narrow genetic base of the cultivated tomato, Solanum lycopersicum L., necessitates introgression of new variation from related species. Wild tomato species represent a rich source of useful genes and traits. Exploitation of genetic variation within wild species can be facilitated by the use of molecular markers and genetic maps. Recently we identified an accession (LA2093) within the red-fruited wild tomato species Solanum pimpinellifolium L. with exceptionally desirable characteristics, including disease resistance, abiotic stress tolerance, and high fruit lycopene content. To facilitate genetic characterization of such traits and their exploitation in tomato crop improvement, we developed a new recombinant inbred line (RIL) population from a cross between LA2093 and an advanced tomato breeding line (NCEBR-1). Furthermore, we constructed a medium-density molecular linkage map of this population using 294 polymorphic markers, including standard RFLPs, EST sequences (used as RFLP probes), CAPS, and SSRs. The map spanned 1091 cM of the tomato genome with an average marker spacing of 3.7 cM. A majority of the EST sequences, which were mainly chosen based on the putative role of their unigenes in disease resistance, defense-related response, or fruit quality, were mapped onto the tomato chromosomes for the first time. Co-localizations of relevant EST sequences with known disease resistance genes in tomato were also examined. This map will facilitate identification, genetic exploitation, and positional cloning of important genes or quantitative trait loci in LA2093. It also will allow the elucidation of the molecular mechanism(s) underlying important traits segregating in the RIL population. The map may further facilitate characterization and exploitation of genetic variation in other S. pimpinellifolium accessions as well as in modern cultivars of tomato.
Collapse
Affiliation(s)
- Hamid Ashrafi
- Department of Horticulture, The Pennsylvania State University, University Park, PA 16802, USA
| | | | | |
Collapse
|
24
|
Aboul-Soud MAM, Chen X, Kang JG, Yun BW, Raja MU, Malik SI, Loake GJ. Activation tagging of ADR2 conveys a spreading lesion phenotype and resistance to biotrophic pathogens. THE NEW PHYTOLOGIST 2009; 183:1163-1175. [PMID: 19549129 DOI: 10.1111/j.1469-8137.2009.02902.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
An Arabidopsis PR1::luciferase (LUC) transgenic line was transformed with activation T-DNA tags and the resulting population screened for dominant gain-of-function mutants exhibiting constitutive LUC activity. LUC imaging identified activated disease resistance 2 (adr2), which exhibited slowly spreading lesions in the absence of pathogen challenge. Molecular, genetic and histochemical analysis was employed to characterize this mutant in detail. adr2 plants constitutively expressed defence-related and antioxidant genes. Moreover, this line accrued increased quantities of salicylic acid (SA) and exhibited heightened mitogen-activated protein kinase activity. adr2 plants exhibited increased resistance against numerous biotrophic but not necrotrophic pathogens. The adr2 phenotype resulted from the overexpression of a Toll interleukin receptor (TIR) nucleotide binding site (NBS) leucine rich repeat (LRR) gene (At1g56510). Constitutive PR1 expression was completely abolished in adr2 nahG, adr2 npr1 and adr2 eds1 double mutants. Furthermore, heightened resistance against Hyaloperonospora arabidopsis Noco2 was compromised in adr2 nahG and adr2 eds1 double mutants but not in adr2 npr1, adr2 coi1 or adr2 etr1 plants. These data imply that adr2-mediated resistance operates through an Enhanced Disease Susceptibility (EDS) and SA-dependent defence signalling network which functions independently from COI1 or ETR1.
Collapse
Affiliation(s)
- Mourad A M Aboul-Soud
- College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Kingdom of Saudi Arabia
| | - Xinwei Chen
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, UK
| | - Jeong-Gu Kang
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, UK
| | - Byung-Wook Yun
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, UK
| | - M Usman Raja
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, UK
| | - Saad I Malik
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, UK
| | - Gary J Loake
- Institute of Molecular Plant Sciences, School of Biological Sciences, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, UK
| |
Collapse
|
25
|
Tedman-Jones JD, Lei R, Jay F, Fabro G, Li X, Reiter WD, Brearley C, Jones JDG. Characterization of Arabidopsis mur3 mutations that result in constitutive activation of defence in petioles, but not leaves. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2008; 56:691-703. [PMID: 18657237 DOI: 10.1111/j.1365-313x.2008.03636.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
A screen was established for mutants in which the plant defence response is de-repressed. The pathogen-inducible isochorismate synthase (ICS1) promoter was fused to firefly luciferase (luc) and a homozygous transgenic line generated in which the ICS1:luc fusion is co-regulated with ICS1. This line was mutagenized and M(2) seedlings screened for constitutive ICS1:luc expression (cie). The cie mutants fall into distinct phenotypic classes based on tissue-specific localization of luciferase activity. One mutant, cie1, that shows constitutive luciferase activity specifically in petioles, was chosen for further analysis. In addition to ICS1, PR and other defence-related genes are constitutively expressed in cie1 plants. The cie1 mutant is also characterized by an increased production of conjugated salicylic acid and reactive oxygen intermediates, as well as spontaneous lesion formation, all confined to petiole tissue. Significantly, defences activated in cie1 are sufficient to prevent infection by a virulent isolate of Hyaloperonospora parasitica, and this enhanced resistance response protects petiole tissue alone. Furthermore, cie1-mediated resistance, along with PR gene expression, is abolished in a sid2-1 mutant background, consistent with a requirement for salicylic acid. A positional cloning approach was used to identify cie1, which carries two point mutations in a gene required for cell wall biosynthesis and actin organization, MUR3. A mur3 knockout mutant also resists infection by H. parasitica in its petioles and this phenotype is complemented by transformation with wild-type MUR3. We propose that perturbed cell wall biosynthesis may activate plant defence and provide a rationale for the cie1 and the mur3 knockout phenotypes.
Collapse
MESH Headings
- Actins/metabolism
- Alleles
- Arabidopsis/genetics
- Arabidopsis/immunology
- Arabidopsis/metabolism
- Arabidopsis Proteins/genetics
- Arabidopsis Proteins/metabolism
- Cell Wall/genetics
- Cell Wall/metabolism
- Chromosome Mapping
- Cloning, Molecular
- Galactosyltransferases/genetics
- Galactosyltransferases/metabolism
- Gene Expression Regulation, Plant
- Gene Knockout Techniques
- Genes, Plant
- Genes, Reporter
- Genetic Complementation Test
- Immunity, Innate
- Intramolecular Transferases/genetics
- Intramolecular Transferases/metabolism
- Mutagenesis
- Plant Leaves/genetics
- Plant Leaves/immunology
- Plant Leaves/metabolism
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/immunology
- Plants, Genetically Modified/metabolism
- Point Mutation
- Promoter Regions, Genetic
- RNA, Plant/genetics
- Reactive Oxygen Species/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Salicylic Acid/metabolism
Collapse
|
26
|
Fabro G, Di Rienzo JA, Voigt CA, Savchenko T, Dehesh K, Somerville S, Alvarez ME. Genome-wide expression profiling Arabidopsis at the stage of Golovinomyces cichoracearum haustorium formation. PLANT PHYSIOLOGY 2008; 146:1421-39. [PMID: 18218973 PMCID: PMC2259087 DOI: 10.1104/pp.107.111286] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2007] [Accepted: 01/08/2008] [Indexed: 05/21/2023]
Abstract
Compatibility between plants and obligate biotrophic fungi requires fungal mechanisms for efficiently obtaining nutrients and counteracting plant defenses under conditions that are expected to induce changes in the host transcriptome. A key step in the proliferation of biotrophic fungi is haustorium differentiation. Here we analyzed global gene expression patterns in Arabidopsis thaliana leaves during the formation of haustoria by Golovinomyces cichoracearum. At this time, the endogenous levels of salicylic acid (SA) and jasmonic acid (JA) were found to be enhanced. The responses of wild-type, npr1-1, and jar1-1 plants were used to categorize the sensitivity of gene expression changes to NPR1 and JAR1, which are components of the SA and JA signaling pathways, respectively. We found that the infection process was the major source of variation, with 70 genes identified as having similarly altered expression patterns regardless of plant genotype. In addition, principal component analysis (PCA) identified genes responding both to infection and to lack of functional JAR1 (17 genes) or NPR1 (18 genes), indicating that the JA and SA signaling pathways function as secondary sources of variation. Participation of these genes in the SA or JA pathways had not been described previously. We found that some of these genes may be sensitive to the balance between the SA and JA pathways, representing novel markers for the elucidation of cross-talk points between these signaling cascades. Conserved putative regulatory motifs were found in the promoter regions of each subset of genes. Collectively, our results indicate that gene expression changes in response to infection by obligate biotrophic fungi may support fungal nutrition by promoting alterations in host metabolism. In addition, these studies provide novel markers for the characterization of defense pathways and susceptibility features under this infection condition.
Collapse
Affiliation(s)
- Georgina Fabro
- CIQUIBIC-CONICET, Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | | | | | | | | | | | | |
Collapse
|
27
|
Ogawa D, Nakajima N, Tamaoki M, Aono M, Kubo A, Kamada H, Saji H. The isochorismate pathway is negatively regulated by salicylic acid signaling in O3-exposed Arabidopsis. PLANTA 2007; 226:1277-85. [PMID: 17588170 DOI: 10.1007/s00425-007-0556-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2007] [Accepted: 05/15/2007] [Indexed: 05/12/2023]
Abstract
Ozone (O3), a major photochemical oxidant, causes leaf injury in plants. Plants synthesize salicylic acid (SA), which is reported to greatly affect O3 sensitivity. However, the mechanism of SA biosynthesis under O3 exposure remains unclear. Plants synthesize SA either by a pathway involving phenylalanine as a substrate or another involving isochorismate. To clarify how SA is produced in O3-exposed Arabidopsis, we examined the activities of phenylalanine ammonia lyase (PAL) and isochorismate synthase (ICS), which are components of the phenylalanine and isochorismate pathways, respectively. Exposure of Arabidopsis to O3 enhanced the accumulation of SA and the increase of ICS activity but did not affect PAL activity. In sid2 mutants, which have a defect in ICS1, the level of SA and the activity of ICS did not increase in response to O3 exposure. These results suggest that SA is mainly synthesized from isochorismate in Arabidopsis. Furthermore, the level of ICS1 expression and the activity of ICS during O3 exposure elevated in plants deficient for SA signaling (npr1 and eds5 mutants and NahG transgenics). Treatment of plants with SA also suppressed the enhancement of ICS1 expression by O3. These results suggest that SA synthesis is negatively regulated by SA signaling.
Collapse
Affiliation(s)
- Daisuke Ogawa
- Graduate School of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan
| | | | | | | | | | | | | |
Collapse
|
28
|
Zarate SI, Kempema LA, Walling LL. Silverleaf whitefly induces salicylic acid defenses and suppresses effectual jasmonic acid defenses. PLANT PHYSIOLOGY 2007; 143:866-75. [PMID: 17189328 PMCID: PMC1803729 DOI: 10.1104/pp.106.090035] [Citation(s) in RCA: 409] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The basal defenses important in curtailing the development of the phloem-feeding silverleaf whitefly (Bemisia tabaci type B; SLWF) on Arabidopsis (Arabidopsis thaliana) were investigated. Sentinel defense gene RNAs were monitored in SLWF-infested and control plants. Salicylic acid (SA)-responsive gene transcripts accumulated locally (PR1, BGL2, PR5, SID2, EDS5, PAD4) and systemically (PR1, BGL2, PR5) during SLWF nymph feeding. In contrast, jasmonic acid (JA)- and ethylene-dependent RNAs (PDF1.2, VSP1, HEL, THI2.1, FAD3, ERS1, ERF1) were repressed or not modulated in SLWF-infested leaves. To test for a role of SA and JA pathways in basal defense, SLWF development on mutant and transgenic lines that constitutively activate or impair defense pathways was determined. By monitoring the percentage of SLWF nymphs in each instar, we show that mutants that activate SA defenses (cim10) or impair JA defenses (coi1) accelerated SLWF nymphal development. Reciprocally, mutants that activate JA defenses (cev1) or impair SA defenses (npr1, NahG) slowed SLWF nymphal development. Furthermore, when npr1 plants, which do not activate downstream SA defenses, were treated with methyl jasmonate, a dramatic delay in nymph development was observed. Collectively, these results showed that SLWF-repressed, JA-regulated defenses were associated with basal defense to the SLWF.
Collapse
Affiliation(s)
- Sonia I Zarate
- Department of Botany and Plant Sciences, Center for Plant Cell Biology, University of California, Riverside, California 92521-0124, USA
| | | | | |
Collapse
|
29
|
Zhang Y, Cheng YT, Qu N, Zhao Q, Bi D, Li X. Negative regulation of defense responses in Arabidopsis by two NPR1 paralogs. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2006; 48:647-56. [PMID: 17076807 DOI: 10.1111/j.1365-313x.2006.02903.x] [Citation(s) in RCA: 151] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
NPR1 is required for systemic acquired resistance, and there are five NPR1 paralogs in Arabidopsis. Here we report knockout analysis of two of these, NPR3 and NPR4. npr3 single mutants have elevated basal PR-1 expression and the npr3 npr4 double mutant shows even higher expression. The double mutant plants also display enhanced resistance against virulent bacterial and oomycete pathogens. This enhanced disease resistance is partially dependent on NPR1, can be in part complemented by either wild-type NPR3 or NPR4, and is not associated with an elevated level of salicylic acid. NPR3 and NPR4 interact with TGA2, TGA3, TGA5 and TGA6 in yeast two-hybrid assays. Using bimolecular fluorescence complementation analysis, we show that NPR3 interacts with TGA2 in the nucleus of onion epidermal cells and Arabidopsis mesophyll protoplasts. Combined with our previous finding that basal PR-1 levels are also elevated in the tga2 tga5 tga6 triple mutant, we propose that NPR3 and NPR4 negatively regulate PR gene expression and pathogen resistance through their association with TGA2 and its paralogs.
Collapse
Affiliation(s)
- Yuelin Zhang
- National Institute of Biological Sciences, #7 Science Park Road, Zhongguancun Life Science Park, Beijing, People's Republic of China 102206.
| | | | | | | | | | | |
Collapse
|
30
|
Mosher RA, Durrant WE, Wang D, Song J, Dong X. A comprehensive structure-function analysis of Arabidopsis SNI1 defines essential regions and transcriptional repressor activity. THE PLANT CELL 2006; 18:1750-65. [PMID: 16766691 PMCID: PMC1488919 DOI: 10.1105/tpc.105.039677] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
The expression of systemic acquired resistance (SAR) in plants involves the upregulation of many Pathogenesis-Related (PR) genes, which work in concert to confer resistance to a broad spectrum of pathogens. Because SAR is a costly process, SAR-associated transcription must be tightly regulated. Arabidopsis thaliana SNI1 (for Suppressor of NPR1, Inducible) is a negative regulator of SAR required to dampen the basal expression of PR genes. Whole genome transcriptional profiling showed that in the sni1 mutant, Nonexpresser of PR genes (NPR1)-dependent benzothiadiazole S-methylester-responsive genes were specifically derepressed. Interestingly, SNI1 also repressed transcription when expressed in yeast, suggesting that it functions as an active transcriptional repressor through a highly conserved mechanism. Chromatin immunoprecipitation indicated that histone modification may be involved in SNI1-mediated repression. Sequence comparison with orthologs in other plant species and a saturating NAAIRS-scanning mutagenesis of SNI1 identified regions in SNI1 that are required for its activity. The structural similarity of SNI1 to Armadillo repeat proteins implies that SNI1 may form a scaffold for interaction with proteins that modulate transcription.
Collapse
Affiliation(s)
- Rebecca A Mosher
- Developmental, Cell, and Molecular Biology Group, Department of Biology, Duke University, Durham, North Carolina 27708, USA
| | | | | | | | | |
Collapse
|
31
|
Stein M, Dittgen J, Sánchez-Rodríguez C, Hou BH, Molina A, Schulze-Lefert P, Lipka V, Somerville S. Arabidopsis PEN3/PDR8, an ATP binding cassette transporter, contributes to nonhost resistance to inappropriate pathogens that enter by direct penetration. THE PLANT CELL 2006; 18:731-46. [PMID: 16473969 PMCID: PMC1383646 DOI: 10.1105/tpc.105.038372] [Citation(s) in RCA: 455] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Arabidopsis thaliana is a host to the powdery mildew Erysiphe cichoracearum and nonhost to Blumeria graminis f. sp hordei, the powdery mildew pathogenic on barley (Hordeum vulgare). Screening for Arabidopsis mutants deficient in resistance to barley powdery mildew identified PENETRATION3 (PEN3). pen3 plants permitted both increased invasion into epidermal cells and initiation of hyphae by B. g. hordei, suggesting that PEN3 contributes to defenses at the cell wall and intracellularly. pen3 mutants were compromised in resistance to the necrotroph Plectosphaerella cucumerina and to two additional inappropriate biotrophs, pea powdery mildew (Erysiphe pisi) and potato late blight (Phytophthora infestans). Unexpectedly, pen3 mutants were resistant to E. cichoracearum. This resistance was salicylic acid-dependent and correlated with chlorotic patches. Consistent with this observation, salicylic acid pathway genes were hyperinduced in pen3 relative to the wild type. The phenotypes conferred by pen3 result from the loss of function of PLEIOTROPIC DRUG RESISTANCE8 (PDR8), a highly expressed putative ATP binding cassette transporter. PEN3/PDR8 tagged with green fluorescent protein localized to the plasma membrane in uninfected cells. In infected leaves, the protein concentrated at infection sites. PEN3/PDR8 may be involved in exporting toxic materials to attempted invasion sites, and intracellular accumulation of these toxins in pen3 may secondarily activate the salicylic acid pathway.
Collapse
Affiliation(s)
- Mónica Stein
- Carnegie Institution, Department of Plant Biology, Stanford, California, 94305, USA
| | | | | | | | | | | | | | | |
Collapse
|
32
|
Sun W, Dunning FM, Pfund C, Weingarten R, Bent AF. Within-species flagellin polymorphism in Xanthomonas campestris pv campestris and its impact on elicitation of Arabidopsis FLAGELLIN SENSING2-dependent defenses. THE PLANT CELL 2006; 18:764-79. [PMID: 16461584 PMCID: PMC1383648 DOI: 10.1105/tpc.105.037648] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Bacterial flagellins have been portrayed as a relatively invariant pathogen-associated molecular pattern. We have found within-species, within-pathovar variation for defense-eliciting activity of flagellins among Xanthomonas campestris pv campestris (Xcc) strains. Arabidopsis thaliana FLAGELLIN SENSING2 (FLS2), a transmembrane leucine-rich repeat kinase, confers flagellin responsiveness. The flg22 region was the only Xcc flagellin region responsible for detectable elicitation of Arabidopsis defense responses. A Val-43/Asp polymorphism determined the eliciting/noneliciting nature of Xcc flagellins (structural gene fliC). Arabidopsis detected flagellins carrying Asp-43 or Asn-43 but not Val-43 or Ala-43, and it responded minimally for Glu-43. Wild-type Xcc strains carrying nonrecognized flagellin were more virulent than those carrying a recognized flagellin when infiltrated into Arabidopsis leaf mesophyll, but this correlation was misleading. Isogenic Xcc fliC gene replacement strains expressing eliciting or noneliciting flagellins grew similarly, both in leaf mesophyll and in hydathode/vascular colonization assays. The plant FLS2 genotype also had no detectable effect on disease outcome when previously untreated plants were infected by Xcc. However, resistance against Xcc was enhanced if FLS2-dependent responses were elicited 1 d before Xcc infection. Prior immunization was not required for FLS2-dependent restriction of Pseudomonas syringae pv tomato. We conclude that plant immune systems do not uniformly detect all flagellins of a particular pathogen species and that Xcc can evade Arabidopsis FLS2-mediated defenses unless the FLS2 system has been activated by previous infections.
Collapse
Affiliation(s)
- Wenxian Sun
- Department of Plant Pathology, University of Wisconsin, Madison, Wisconsin 53705, USA
| | | | | | | | | |
Collapse
|
33
|
Mur LAJ, Kenton P, Atzorn R, Miersch O, Wasternack C. The outcomes of concentration-specific interactions between salicylate and jasmonate signaling include synergy, antagonism, and oxidative stress leading to cell death. PLANT PHYSIOLOGY 2006; 140:249-62. [PMID: 16377744 PMCID: PMC1326048 DOI: 10.1104/pp.105.072348] [Citation(s) in RCA: 499] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2005] [Revised: 11/18/2005] [Accepted: 11/21/2005] [Indexed: 05/05/2023]
Abstract
Salicylic acid (SA) has been proposed to antagonize jasmonic acid (JA) biosynthesis and signaling. We report, however, that in salicylate hydroxylase-expressing tobacco (Nicotiana tabacum) plants, where SA levels were reduced, JA levels were not elevated during a hypersensitive response elicited by Pseudomonas syringae pv phaseolicola. The effects of cotreatment with various concentrations of SA and JA were assessed in tobacco and Arabidopsis (Arabidopsis thaliana). These suggested that there was a transient synergistic enhancement in the expression of genes associated with either JA (PDF1.2 [defensin] and Thi1.2 [thionin]) or SA (PR1 [PR1a-beta-glucuronidase in tobacco]) signaling when both signals were applied at low (typically 10-100 microm) concentrations. Antagonism was observed at more prolonged treatment times or at higher concentrations. Similar results were also observed when adding the JA precursor, alpha-linolenic acid with SA. Synergic effects on gene expression and plant stress were NPR1- and COI1-dependent, SA- and JA-signaling components, respectively. Electrolyte leakage and Evans blue staining indicated that application of higher concentrations of SA + JA induced plant stress or death and elicited the generation of apoplastic reactive oxygen species. This was indicated by enhancement of hydrogen peroxide-responsive AoPR10-beta-glucuronidase expression, suppression of plant stress/death using catalase, and direct hydrogen peroxide measurements. Our data suggests that the outcomes of JA-SA interactions could be tailored to pathogen/pest attack by the relative concentration of each hormone.
Collapse
Affiliation(s)
- Luis A J Mur
- Institute of Biological Science, University of Wales, Aberystwyth, United Kingdom.
| | | | | | | | | |
Collapse
|
34
|
Mur LAJ, Kenton P, Atzorn R, Miersch O, Wasternack C. The outcomes of concentration-specific interactions between salicylate and jasmonate signaling include synergy, antagonism, and oxidative stress leading to cell death. PLANT PHYSIOLOGY 2006; 140:249-262. [PMID: 16377744 DOI: 10.2307/4282048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Salicylic acid (SA) has been proposed to antagonize jasmonic acid (JA) biosynthesis and signaling. We report, however, that in salicylate hydroxylase-expressing tobacco (Nicotiana tabacum) plants, where SA levels were reduced, JA levels were not elevated during a hypersensitive response elicited by Pseudomonas syringae pv phaseolicola. The effects of cotreatment with various concentrations of SA and JA were assessed in tobacco and Arabidopsis (Arabidopsis thaliana). These suggested that there was a transient synergistic enhancement in the expression of genes associated with either JA (PDF1.2 [defensin] and Thi1.2 [thionin]) or SA (PR1 [PR1a-beta-glucuronidase in tobacco]) signaling when both signals were applied at low (typically 10-100 microm) concentrations. Antagonism was observed at more prolonged treatment times or at higher concentrations. Similar results were also observed when adding the JA precursor, alpha-linolenic acid with SA. Synergic effects on gene expression and plant stress were NPR1- and COI1-dependent, SA- and JA-signaling components, respectively. Electrolyte leakage and Evans blue staining indicated that application of higher concentrations of SA + JA induced plant stress or death and elicited the generation of apoplastic reactive oxygen species. This was indicated by enhancement of hydrogen peroxide-responsive AoPR10-beta-glucuronidase expression, suppression of plant stress/death using catalase, and direct hydrogen peroxide measurements. Our data suggests that the outcomes of JA-SA interactions could be tailored to pathogen/pest attack by the relative concentration of each hormone.
Collapse
Affiliation(s)
- Luis A J Mur
- Institute of Biological Science, University of Wales, Aberystwyth, United Kingdom.
| | | | | | | | | |
Collapse
|
35
|
Tang D, Ade J, Frye CA, Innes RW. Regulation of plant defense responses in Arabidopsis by EDR2, a PH and START domain-containing protein. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 44:245-57. [PMID: 16212604 PMCID: PMC1797612 DOI: 10.1111/j.1365-313x.2005.02523.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
We have identified an Arabidopsis mutant that displays enhanced disease resistance (edr2) to the biotrophic powdery mildew pathogen Erysiphe cichoracearum. Inhibition of fungal growth on edr2 mutant leaves occurred at a late stage of the infection process and coincided with formation of necrotic lesions approximately 5 days after inoculation. Double-mutant analysis revealed that edr2-mediated resistance is suppressed by mutations that inhibit salicylic acid (SA)-induced defense signaling, including npr1, pad4 and sid2, demonstrating that edr2-mediated disease resistance is dependent on SA. However, edr2 showed normal responses to the bacterial pathogen Pseudomonas syringae pv. tomato strain DC3000. EDR2 appears to be constitutively transcribed in all tissues and organs and encodes a novel protein, consisting of a putative pleckstrin homology (PH) domain and a steroidogenic acute regulatory protein-related lipid-transfer (START) domain, and contains an N-terminal mitochondrial targeting sequence. The PH and START domains are implicated in lipid binding, suggesting that EDR2 may provide a link between lipid signaling and activation of programmed cell death mediated by mitochondria.
Collapse
Affiliation(s)
- Dingzhong Tang
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | | | | | | |
Collapse
|
36
|
Ahn IP, Kim S, Lee YH. Vitamin B1 functions as an activator of plant disease resistance. PLANT PHYSIOLOGY 2005; 138:1505-15. [PMID: 15980201 PMCID: PMC1176421 DOI: 10.1104/pp.104.058693] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Revised: 03/28/2005] [Accepted: 04/04/2005] [Indexed: 05/03/2023]
Abstract
Vitamin B(1) (thiamine) is an essential nutrient for humans. Vitamin B(1) deficiency causes beriberi, which disturbs the central nervous and circulatory systems. In countries in which rice (Oryza sativa) is a major food, thiamine deficiency is prevalent because polishing of rice removes most of the thiamine in the grain. We demonstrate here that thiamine, in addition to its nutritional value, induces systemic acquired resistance (SAR) in plants. Thiamine-treated rice, Arabidopsis (Arabidopsis thaliana), and vegetable crop plants showed resistance to fungal, bacterial, and viral infections. Thiamine treatment induces the transient expression of pathogenesis-related (PR) genes in rice and other plants. In addition, thiamine treatment potentiates stronger and more rapid PR gene expression and the up-regulation of protein kinase C activity. The effects of thiamine on disease resistance and defense-related gene expression mobilize systemically throughout the plant and last for more than 15 d after treatment. Treatment of Arabidopsis ecotype Columbia-0 plants with thiamine resulted in the activation of PR-1 but not PDF1.2. Furthermore, thiamine prevented bacterial infection in Arabidopsis mutants insensitive to jasmonic acid or ethylene but not in mutants impaired in the SAR transduction pathway. These results clearly demonstrate that thiamine induces SAR in plants through the salicylic acid and Ca(2+)-related signaling pathways. The findings provide a novel paradigm for developing alternative strategies for the control of plant diseases.
Collapse
Affiliation(s)
- Il-Pyung Ahn
- School of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-742, Korea
| | | | | |
Collapse
|
37
|
Serrano M, Guzmán P. Isolation and gene expression analysis of Arabidopsis thaliana mutants with constitutive expression of ATL2, an early elicitor-response RING-H2 zinc-finger gene. Genetics 2005; 167:919-29. [PMID: 15238540 PMCID: PMC1470891 DOI: 10.1534/genetics.104.028043] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Genes with unstable transcripts often encode proteins that play important regulatory roles. ATL2 is a member of a multigene family coding highly related RING-H2 zinc-finger proteins that may function as E3 ubiquitin ligases. ATL2 mRNA accumulation occurs rapidly and transiently after incubation with elicitors of pathogen response. We screened 50,000 M(2) families from a line that carries a fusion of pATL2 to the GUS reporter gene and isolated five mutants, which we named eca (expresión constitutiva de ATL2), that showed constitutive expression of the reporter gene. One mutant exhibits a drastic stunted phenotype while the other four grow similarly to wild type. Two early chitin-induced genes and known pathogenesis-related genes such as NPR1, PAL, and CHS are activated in all the mutants whereas members of the ATL family and PR-1 and PDF2.1, which are markers of the salicylic acid (SA) jasmonate (JA) defense-response pathways, display differential expression between the mutants. These observations indicate that the ECA gene products may function in the early steps of an elicitor-response pathway, although some of them may function at other stages on the SA or JA defense-response pathways. Likewise, the fact that ATL2 and other members of the ATL family are activated in eca mutants links the induction of this putative class of ubiquitin ligases to plant defense signaling pathways.
Collapse
Affiliation(s)
- Mario Serrano
- Departamento de Ingeniería Genética de Plantas, Centro de Investigación y de Estudios Avanzados del IPN, Unidad Irapuato, Irapuato 36500, México
| | | |
Collapse
|
38
|
Murray SL, Adams N, Kliebenstein DJ, Loake GJ, Denby KJ. A constitutive PR-1::luciferase expression screen identifies Arabidopsis mutants with differential disease resistance to both biotrophic and necrotrophic pathogens. MOLECULAR PLANT PATHOLOGY 2005; 6:31-41. [PMID: 20565636 DOI: 10.1111/j.1364-3703.2004.00261.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
SUMMARY A complex signal transduction network involving salicylic acid, jasmonic acid and ethylene underlies disease resistance in Arabidopsis. To understand this defence signalling network further, we identified mutants that expressed the marker gene PR-1::luciferase in the absence of pathogen infection. These cir mutants all display constitutive expression of a suite of defence-related genes but exhibit different disease resistance profiles to two biotrophic pathogens, Pseudomonas syringae pv. tomato and Peronospora parasitica NOCO2, and the necrotrophic pathogen Botrytis cinerea. We further characterized cir3, which displays enhanced resistance only to the necrotrophic pathogen. Cir3-mediated resistance to B. cinerea is dependent on accumulated salicylic acid and a functional EIN2 protein.
Collapse
Affiliation(s)
- Shane L Murray
- Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, 7701, South Africa
| | | | | | | | | |
Collapse
|
39
|
Veronese P, Chen X, Bluhm B, Salmeron J, Dietrich R, Mengiste T. The BOS loci of Arabidopsis are required for resistance to Botrytis cinerea infection. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 40:558-74. [PMID: 15500471 DOI: 10.1111/j.1365-313x.2004.02232.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Three Botrytis-susceptible mutants bos2, bos3, and bos4 which define independent and novel genetic loci required for Arabidopsis resistance to Botrytis cinerea were isolated. The bos2 mutant is susceptible to B. cinerea but retains wild-type levels of resistance to other pathogens tested, indicative of a defect in a response pathway more specific to B. cinerea. The bos3 and bos4 mutants also show increased susceptibility to Alternaria brassicicola, another necrotrophic pathogen, suggesting a broader role for these loci in resistance. bos4 shows the broadest range of effects on resistance, being more susceptible to avirulent strain of Pseudomonas syringae pv. tomato. Interestingly, bos3 is more resistant than wild-type plants to virulent strains of the biotrophic pathogen Peronospora parasitica and the bacterial pathogen P. syringae pv. tomato. The Pathogenesis Related gene 1 (PR-1), a molecular marker of the salicylic acid (SA)-dependent resistance pathway, shows a wild-type pattern of expression in bos2, while in bos3 this gene was expressed at elevated levels, both constitutively and in response to pathogen challenge. In bos4 plants, PR-1 expression was reduced compared with wild type in response to B. cinerea and SA. In bos3, the mutant most susceptible to B. cinerea and with the highest expression of PR-1, removal of SA resulted in reduced PR-1 expression but no change to the B. cinerea response. Expression of the plant defensin gene PDF1-2 was generally lower in bos mutants compared with wild-type plants, with a particularly strong reduction in bos3. Production of the phytoalexin camalexin is another well-characterized plant defense response. The bos2 and bos4 mutants accumulate reduced levels of camalexin whereas bos3 accumulates significantly higher levels of camalexin than wild-type plants in response to B. cinerea. The BOS2, BOS3, and BOS4 loci may affect camalexin levels and responsiveness to ethylene and jasmonate. The three new mutants appear to mediate disease responses through mechanisms independent of the previously described BOS1 gene. Based on the differences in the phenotypes of the bos mutants, it appears that they affect different points in defense response pathways.
Collapse
Affiliation(s)
- Paola Veronese
- Department of Botany and Plant Pathology, Purdue University, 915 W. State Street, West Lafayette, IN 47907-2054, USA
| | | | | | | | | | | |
Collapse
|
40
|
Pfund C, Tans-Kersten J, Dunning FM, Alonso JM, Ecker JR, Allen C, Bent AF. Flagellin is not a major defense elicitor in Ralstonia solanacearum cells or extracts applied to Arabidopsis thaliana. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2004; 17:696-706. [PMID: 15195952 DOI: 10.1094/mpmi.2004.17.6.696] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The phytopathogenic bacterium Ralstonia solanacearum requires motility for full virulence, and its flagellin is a candidate pathogen-associated molecular pattern that may elicit plant defenses. Boiled extracts from R. solanacearum contained a strong elicitor of defense-associated responses. However, R. solanacearum flagellin is not this elicitor, because extracts from wild-type bacteria and fliC or flhDC mutants defective in flagellin production all elicited similar plant responses. Equally important, live R. solanacearum caused similar disease on Arabidopsis ecotype Col-0, regardless of the presence of flagellin in the bacterium or the FLS2-mediated flagellin recognition system in the plant. Unlike the previously studied flg22 flagellin peptide, a peptide based on the corresponding conserved N-terminal segment of R. solanacearum, flagellin did not elicit any response from Arabidopsis seedlings. Thus recognition of flagellin plays no readily apparent role in this pathosystem. Flagellin also was not the primary elicitor of responses in tobacco. The primary eliciting activity in boiled R. solanacearum extracts applied to Arabidopsis was attributable to one or more proteins other than flagellin, including species purifying at approximately 5 to 10 kDa and also at larger molecular masses, possibly due to aggregation. Production of this eliciting activity did not require hrpB (positive regulator of type III secretion), pehR (positive regulator of polygalacturonase production and motility), gspM (general secretion pathway), or phcA (LysR-type global virulence regulator). Wild-type R. solanacearum was virulent on Arabidopsis despite the presence of this elicitor in pathogen extracts.
Collapse
Affiliation(s)
- Christine Pfund
- Department of Plant Pathology, University of Wisconsin, Madison, 1630 Linden Drive, Madison, WI 53706, USA
| | | | | | | | | | | | | |
Collapse
|
41
|
Serrano RL, Kuhn A, Hendricks A, Helms JB, Sinning I, Groves MR. Structural Analysis of the Human Golgi-associated Plant Pathogenesis Related Protein GAPR-1 Implicates Dimerization as a Regulatory Mechanism. J Mol Biol 2004; 339:173-83. [PMID: 15123429 DOI: 10.1016/j.jmb.2004.03.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Revised: 03/03/2004] [Accepted: 03/04/2004] [Indexed: 11/24/2022]
Abstract
The plant pathogenesis related proteins group 1 (PR-1) and a variety of related mammalian proteins constitute a PR-1 protein family that share sequence and structural similarities. GAPR-1 is a unique family member as thus far it is the only PR-1 family member that is not co-translationally targeted to the lumen of the endoplasmic reticulum before trafficking to either vacuoles or secretion. Here we report that GAPR-1 may form dimers in vitro and in vivo, as determined by yeast two-hybrid screening, biochemical and biophysical assays. The 1.55A crystal structure demonstrates that GAPR-1 is structurally homologous to the other PR-1 family members previously solved (p14a and Ves V 5). Through an examination of inter-molecular interactions between GAPR-1 molecules in the crystal lattice, we propose a number of the highly conserved amino acid residues of the PR-1 family to be involved in the regulation of dimer formation of GAPR-1 with potential implications for other PR-1 family members. We show that mutagenesis of these conserved amino acid residues leads to a greatly increased dimer population. A recent report suggests that PR-1 family members may exhibit serine protease activity and further examination of the dimer interface of GAPR-1 indicates that a catalytic triad similar to that of serine proteases may be formed across the dimer interface by residues from both molecules within the dimer.
Collapse
Affiliation(s)
- Ramon L Serrano
- Biochemie-Zentrum Heidelberg, University of Heidelberg, Im Neuenheimerfeld 328, 69120 Heidelberg, Germany
| | | | | | | | | | | |
Collapse
|
42
|
Jurkowski GI, Smith RK, Yu IC, Ham JH, Sharma SB, Klessig DF, Fengler KA, Bent AF. Arabidopsis DND2, a second cyclic nucleotide-gated ion channel gene for which mutation causes the "defense, no death" phenotype. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2004; 17:511-20. [PMID: 15141955 DOI: 10.1094/mpmi.2004.17.5.511] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A previous mutant screen identified Arabidopsis dnd1 and dnd2 "defense, no death" mutants, which exhibit loss of hypersensitive response (HR) cell death without loss of gene-for-gene resistance. The dnd1 phenotype is caused by mutation of the gene encoding cyclic nucleotide-gated (CNG) ion channel AtCNGC2. This study characterizes dnd2 plants. Even in the presence of high titers of Pseudomonas syringae expressing avrRpt2, most leaf mesophyll cells in the dnd2 mutant exhibited no HR. These plants retained strong RPS2-, RPM1-, or RPS4-mediated restriction of P. syringae pathogen growth. Mutant dnd2 plants also exhibited enhanced broad-spectrum resistance against virulent P. syringae and constitutively elevated levels of salicylic acid, and pathogenesis-related (PR) gene expression. Unlike the wild type, dnd2 plants responding to virulent and avirulent P. syringae exhibited elevated expression of both salicylate-dependent PR-1 and jasmonate and ethylene-dependent PDF1.2. Introduction of nahG+ (salicylate hydroxylase) into the dnd2 background, which removes salicylic acid and causes other defense alterations, eliminated constitutive disease resistance and PR gene expression but only weakly impacted the HR- phenotype. Map-based cloning revealed that dnd2 phenotypes are caused by mutation of a second CNG ion channel gene, AtCNGC4. Hence, loss of either of two functionally nonredundant CNG ion channels can cause dnd phenotypes. The dnd mutants provide a unique genetic background for dissection of defense signaling.
Collapse
Affiliation(s)
- Grace I Jurkowski
- Department of Plant Pathology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | | | | | | | | | | | | | | |
Collapse
|
43
|
Grant JJ, Chini A, Basu D, Loake GJ. Targeted activation tagging of the Arabidopsis NBS-LRR gene, ADR1, conveys resistance to virulent pathogens. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2003; 16:669-80. [PMID: 12906111 DOI: 10.1094/mpmi.2003.16.8.669] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
A transgenic Arabidopsis line containing a chimeric PR-1::luciferase (LUC) reporter gene was subjected to mutagenesis with activation tags. Screening of lines via high-throughput LUC imaging identified a number of dominant Arabidopsis mutants that exhibited enhanced PR-1 gene expression. Here, we report the characterization of one of these mutants, designated activated disease resistance (adr) 1. This line showed constitutive expression of a number of key defense marker genes and accumulated salicylic acid but not ethylene or jasmonic acid. Furthermore, adr1 plants exhibited resistance against the biotrophic pathogens Peronospora parasitica and Erysiphe cichoracearum but not the necrotrophic fungus Botrytis cinerea. Analysis of a series of adr1 double mutants suggested that adr1-mediated resistance against P. parasitica was salicylic acid (SA)-dependent, while resistance against E. cichoracearum was both SA-dependent and partially NPR1-dependent. The ADR1 gene encoded a protein possessing a number of key features, including homology to subdomains of protein kinases, a nucleotide binding domain, and leucine-rich repeats. The controlled, transient expression of ADR1 conveyed striking disease resistance in the absence of yield penalty, highlighting the potential utility of this gene in crop protection.
Collapse
Affiliation(s)
- John J Grant
- Institute of Cell and Molecular Biology, University of Edinburgh, King's Buildings, Edinburgh EH9 3JR, UK
| | | | | | | |
Collapse
|
44
|
Ferrari S, Plotnikova JM, De Lorenzo G, Ausubel FM. Arabidopsis local resistance to Botrytis cinerea involves salicylic acid and camalexin and requires EDS4 and PAD2, but not SID2, EDS5 or PAD4. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2003; 35:193-205. [PMID: 12848825 DOI: 10.1046/j.1365-313x.2003.01794.x] [Citation(s) in RCA: 337] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Salicylic acid (SA) is an important regulator of plant defense responses, and a variety of Arabidopsis mutants impaired in resistance against bacterial and fungal pathogens show defects in SA accumulation, perception, or signal transduction. Nevertheless, the role of SA-dependent defense responses against necrotrophic fungi is currently unclear. We determined the susceptibility of a set of previously identified Arabidopsis mutants impaired in defense responses to the necrotrophic fungal pathogen Botrytis cinerea. The rate of development of B. cinerea disease symptoms on primary infected leaves was affected by responses mediated by the genes EIN2, JAR1, EDS4, PAD2, and PAD3, but was largely independent of EDS5, SID2/ICS1, and PAD4. Furthermore, plants expressing a nahG transgene or treated with a phenylalanine ammonia lyase (PAL) inhibitor showed enhanced symptoms, suggesting that SA synthesized via PAL, and not via isochorismate synthase (ICS), mediates lesion development. In addition, the degree of lesion development did not correlate with defensin or PR1 expression, although it was partially dependent upon camalexin accumulation. Although npr1 mutant leaves were normally susceptible to B. cinerea infection, a double ein2 npr1 mutant was significantly more susceptible than ein2 plants, and exogenous application of SA decreased B. cinerea lesion size through an NPR1-dependent mechanism that could be mimicked by the cpr1 mutation. These data indicate that local resistance to B. cinerea requires ethylene-, jasmonate-, and SA-mediated signaling, that the SA affecting this resistance does not require ICS1 and is likely synthesized via PAL, and that camalexin limits lesion development.
Collapse
Affiliation(s)
- Simone Ferrari
- Department of Genetics, Harvard Medical School, Massachusetts General Hospital, Boston, MA 02114, USA
| | | | | | | |
Collapse
|
45
|
Slusarenko AJ, Schlaich NL. Downy mildew of Arabidopsis thaliana caused by Hyaloperonospora parasitica (formerly Peronospora parasitica). MOLECULAR PLANT PATHOLOGY 2003; 4:159-70. [PMID: 20569375 DOI: 10.1046/j.1364-3703.2003.00166.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
UNLABELLED SUMMARY Downy mildew of Arabidopsis is not a hugely destructive disease of an important crop plant, neither is it of any economic importance. The most obvious symptom, the aerial conidiophores, might, at a glance to the casual observer, be mistaken for the trichomes normally present on the leaves. However, a huge research effort is being devoted to this humble pathosystem which became established as a laboratory model in the 1990s. Since then, enormous progress has been made in cloning and characterizing major genes for resistance (RPP genes) and in defining many of their downstream signalling components, some of them RPP-gene specific. Resistance is generally associated with an oxidative burst and a salicylic acid dependent hypersensitive reaction type of programmed cell death. Biological and chemical induction of systemic acquired resistance (SAR) in Arabidopsis protecting against downy mildew were demonstrated early on, and investigations of mutants have contributed fundamentally to our understanding of host-pathogen interactions and the mechanisms of plant defence. This review will attempt to collate the wealth of information which has accrued with this pathosystem in the last decade and will attempt to predict future research directions by drawing attention to some still unanswered questions. TAXONOMY Hyaloperonospora Constant. parasitica (Pers.:Fr) Fr. (formerly Peronospora parasitica), Kingdom Chromista, Phylum Oomycota, Order Peronosporales, Family Peronosporaceae, Genus Hyaloperonospora, of which it is the type species. The taxonomy of the group of organisms causing downy mildew of brassicas has undergone a number of revisions since Corda (1837) originally coined the genus Peronospora. All isolates pathogenic on brassicas were described initially as P. parasitica but Gäumann (1918) classified isolates from different brassicaceous hosts distinctly and thus defined 52 new species based on conidial dimensions and host range. After much debate it was decided to revert to the aggregate species of P. parasitica for all brassica-infecting downy mildews, whilst recognizing that these show some isolate-specific differences (Yerkes and Shaw, 1959). The latest re-examination of P. parasitica by Constantinescu and Fatehi (2002) has placed isolates of P. parasitica and five other downy mildew species in a clear new subgroup on the basis of their hyaline conidiospores, recurved conidiophore branch tips and ITS1, ITS2 and 5.8S rDNA sequence comparisons; meriting the coining of the new genus 'Hyaloperonospora Constant'. The class Oomycetes in the Kingdom Chromista (Straminipila) comprises fungus-like organisms with heterokont zoospores (i.e. possessing two types of flagellae, whiplash and tinsel). The Oomycetes have non-septate hyphae with cellulose-based walls containing very little or no chitin. The latter is regarded as a major distinction separating the Oomycetes from the true fungi, and reports of the presence of chitin had generally been regarded as due to small amounts of contamination (Gams et al., 1998). However, in view of recent studies by Werner et al. (2002) showing a chitin synthase gene in an Oomycete and demonstrating the presence of the polymer itself by an interaction with wheat germ agglutinin (WGA), it is perhaps safe to say that we have not seen the last taxonomic revision which will affect this group! The families within the Oomycetes show a clear evolutionary trend to a lesser absolute dependence on an aqueous environment and some members of the Peronosporales, e.g. H. parasitica, have no zoosporic stage in the life cycle. HOST RANGE Isolates infecting Arabidopsis thaliana have so far proven to be non-pathogenic on other crucifers tested but exist in a clear gene-for-gene relationship with different host ecotypes. Disease symptoms: Infections are first apparent to the naked eye as a carpet or 'down' of conidiophores covering the upper and lower surfaces of leaves and petioles. This symptom is characteristic of this group of diseases and lends it its name. USEFUL WEBSITES <http://ppathw3.cals.cornell.edu/PP644/ references.htm> (links to references on Oomycetes), <http://www.arabidopsis.org/> (TAIR, The Arabidopsis Information Resource).
Collapse
Affiliation(s)
- Alan J Slusarenko
- Department of Plant Physiology (BioIII), RWTH Aachen, Worringerweg 1, D-52056 Aachen, Germany
| | | |
Collapse
|
46
|
Lincoln JE, Richael C, Overduin B, Smith K, Bostock R, Gilchrist DG. Expression of the antiapoptotic baculovirus p35 gene in tomato blocks programmed cell death and provides broad-spectrum resistance to disease. Proc Natl Acad Sci U S A 2002; 99:15217-21. [PMID: 12403830 PMCID: PMC137570 DOI: 10.1073/pnas.232579799] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The sphinganine analog mycotoxin, AAL-toxin, induces a death process in plant and animal cells that shows apoptotic morphology. In nature, the AAL-toxin is the primary determinant of the Alternaria stem canker disease of tomato, thus linking apoptosis to this disease caused by Alternaria alternata f. sp. lycopersici. The product of the baculovirus p35 gene is a specific inhibitor of a class of cysteine proteases termed caspases, and naturally functions in infected insects. Transgenic tomato plants bearing the p35 gene were protected against AAL-toxin-induced death and pathogen infection. Resistance to the toxin and pathogen co-segregated with the expression of the p35 gene through the T3 generation, as did resistance to A. alternata, Colletotrichum coccodes, and Pseudomonas syringae pv. tomato. The p35 gene, stably transformed into tomato roots by Agrobacterium rhizogenes, protected roots against a 30-fold greater concentration of AAL-toxin than control roots tolerated. Transgenic expression of a p35 binding site mutant (DQMD to DRIL), inactive against animal caspases-3, did not protect against AAL-toxin. These results indicate that plants possess a protease with substrate-site specificity that is functionally equivalent to certain animal caspases. A biological conclusion is that diverse plant pathogens co-opt apoptosis during infection, and that transgenic modification of pathways regulating programmed cell death in plants is a potential strategy for engineering broad-spectrum disease resistance in plants.
Collapse
Affiliation(s)
- James E Lincoln
- Center for Engineering Plants for Resistance Against Pathogens, Davis, CA 95616, USA
| | | | | | | | | | | |
Collapse
|