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Li P, Wang Z, Wang X, Liu F, Wang H. Changes in Phytohormones and Transcriptomic Reprogramming in Strawberry Leaves under Different Light Qualities. Int J Mol Sci 2024; 25:2765. [PMID: 38474012 DOI: 10.3390/ijms25052765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 02/18/2024] [Accepted: 02/23/2024] [Indexed: 03/14/2024] Open
Abstract
Strawberry plants require light for growth, but the frequent occurrence of low-light weather in winter can lead to a decrease in the photosynthetic rate (Pn) of strawberry plants. Light-emitting diode (LED) systems could be used to increase Pn. However, the changes in the phytohormones and transcriptomic reprogramming in strawberry leaves under different light qualities are still unclear. In this study, we treated strawberry plants with sunlight, sunlight covered with a 50% sunshade net, no light, blue light (460 nm), red light (660 nm), and a 50% red/50% blue LED light combination for 3 days and 7 days. Our results revealed that the light quality has an effect on the contents of Chl a and Chl b, the minimal fluorescence (F0), and the Pn of strawberry plants. The light quality also affected the contents of abscisic acid (ABA), auxin (IAA), trans-zeatin-riboside (tZ), jasmonic acid (JA), and salicylic acid (SA). RNA sequencing (RNA-seq) revealed that differentially expressed genes (DEGs) are significantly enriched in photosynthesis antenna proteins, photosynthesis, carbon fixation in photosynthetic organisms, porphyrin and chlorophyll metabolisms, carotenoid biosynthesis, tryptophan metabolism, phenylalanine metabolism, zeatin biosynthesis, and linolenic acid metabolism. We then selected the key DEGs based on the results of a weighted gene co-expression network analysis (WGCNA) and drew nine metabolic heatmaps and protein-protein interaction networks to map light regulation.
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Affiliation(s)
- Peng Li
- Institute of Pomology of CAAS, Xingcheng 125100, China
| | - Zhiqiang Wang
- Institute of Pomology of CAAS, Xingcheng 125100, China
| | - Xiaodi Wang
- Institute of Pomology of CAAS, Xingcheng 125100, China
| | - Fengzhi Liu
- Institute of Pomology of CAAS, Xingcheng 125100, China
| | - Haibo Wang
- Institute of Pomology of CAAS, Xingcheng 125100, China
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Chemical inhibition of the auxin inactivation pathway uncovers the roles of metabolic turnover in auxin homeostasis. Proc Natl Acad Sci U S A 2022; 119:e2206869119. [PMID: 35914172 PMCID: PMC9371723 DOI: 10.1073/pnas.2206869119] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The phytohormone auxin, indole-3-acetic acid (IAA), plays a prominent role in plant development. Auxin homeostasis is coordinately regulated by auxin synthesis, transport, and inactivation; however, the physiological contribution of auxin inactivation to auxin homeostasis has not been determined. The GH3 IAA-amino acid conjugating enzymes play a central role in auxin inactivation. Chemical inhibition of GH3 proteins in planta is challenging because the inhibition of these enzymes leads to IAA overaccumulation that rapidly induces GH3 expression. Here, we report the characterization of a potent GH3 inhibitor, kakeimide, that selectively targets IAA-conjugating GH3 proteins. Chemical knockdown of the auxin inactivation pathway demonstrates that auxin turnover is very rapid (about 10 min) and indicates that both auxin biosynthesis and inactivation dynamically regulate auxin homeostasis.
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Naumann C, Heisters M, Brandt W, Janitza P, Alfs C, Tang N, Toto Nienguesso A, Ziegler J, Imre R, Mechtler K, Dagdas Y, Hoehenwarter W, Sawers G, Quint M, Abel S. Bacterial-type ferroxidase tunes iron-dependent phosphate sensing during Arabidopsis root development. Curr Biol 2022; 32:2189-2205.e6. [PMID: 35472311 PMCID: PMC9168544 DOI: 10.1016/j.cub.2022.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 02/21/2022] [Accepted: 04/04/2022] [Indexed: 12/02/2022]
Abstract
Access to inorganic phosphate (Pi), a principal intermediate of energy and nucleotide metabolism, profoundly affects cellular activities and plant performance. In most soils, antagonistic Pi-metal interactions restrict Pi bioavailability, which guides local root development to maximize Pi interception. Growing root tips scout the essential but immobile mineral nutrient; however, the mechanisms monitoring external Pi status are unknown. Here, we show that Arabidopsis LOW PHOSPHATE ROOT 1 (LPR1), one key determinant of Fe-dependent Pi sensing in root meristems, encodes a novel ferroxidase of high substrate specificity and affinity (apparent KM ∼ 2 μM Fe2+). LPR1 typifies an ancient, Fe-oxidizing multicopper protein family that evolved early upon bacterial land colonization. The ancestor of streptophyte algae and embryophytes (land plants) acquired LPR1-type ferroxidase from soil bacteria via horizontal gene transfer, a hypothesis supported by phylogenomics, homology modeling, and biochemistry. Our molecular and kinetic data on LPR1 regulation indicate that Pi-dependent Fe substrate availability determines LPR1 activity and function. Guided by the metabolic lifestyle of extant sister bacterial genera, we propose that Arabidopsis LPR1 monitors subtle concentration differentials of external Fe availability as a Pi-dependent cue to adjust root meristem maintenance via Fe redox signaling and cell wall modification. We further hypothesize that the acquisition of bacterial LPR1-type ferroxidase by embryophyte progenitors facilitated the evolution of local Pi sensing and acquisition during plant terrestrialization. Arabidopsis thaliana LPR1 multicopper oxidase typifies a novel ferroxidase cohort Fe availability tunes LPR1-dependent root responses to phosphate (Pi) limitation LPR1 specificity links Fe-Pi interactions to root Pi sensing via redox cycling Streptophyte ancestors acquired LPR1-type ferroxidase from soil bacteria by HGT
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Lian Q, Fu Q, Xu Y, Hu Z, Zheng J, Zhang A, He Y, Wang C, Xu C, Chen B, Garcia-Mas J, Zhao G, Wang H. QTLs and candidate genes analyses for fruit size under domestication and differentiation in melon (Cucumis melo L.) based on high resolution maps. BMC PLANT BIOLOGY 2021; 21:126. [PMID: 33658004 PMCID: PMC7931605 DOI: 10.1186/s12870-021-02904-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 02/24/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND Melon is a very important horticultural crop produced worldwide with high phenotypic diversity. Fruit size is among the most important domestication and differentiation traits in melon. The molecular mechanisms of fruit size in melon are largely unknown. RESULTS Two high-density genetic maps were constructed by whole-genome resequencing with two F2 segregating populations (WAP and MAP) derived from two crosses (cultivated agrestis × wild agrestis and cultivated melo × cultivated agrestis). We obtained 1,871,671 and 1,976,589 high quality SNPs that show differences between parents in WAP and MAP. A total of 5138 and 5839 recombination events generated 954 bins in WAP and 1027 bins in MAP with the average size of 321.3 Kb and 301.4 Kb respectively. All bins were mapped onto 12 linkage groups in WAP and MAP. The total lengths of two linkage maps were 904.4 cM (WAP) and 874.5 cM (MAP), covering 86.6% and 87.4% of the melon genome. Two loci for fruit size were identified on chromosome 11 in WAP and chromosome 5 in MAP, respectively. An auxin response factor and a YABBY transcription factor were inferred to be the candidate genes for both loci. CONCLUSION The high-resolution genetic maps and QTLs analyses for fruit size described here will provide a better understanding the genetic basis of domestication and differentiation, and provide a valuable tool for map-based cloning and molecular marker assisted breeding.
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Affiliation(s)
- Qun Lian
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture and Rural Affairs, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, 100081, Beijing, China
- Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518000, China
| | - Qiushi Fu
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture and Rural Affairs, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, 100081, Beijing, China
| | - Yongyang Xu
- Henan Key Laboratory of Fruit and Cucurbit Biology, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, China
| | - Zhicheng Hu
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture and Rural Affairs, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, 100081, Beijing, China
| | - Jing Zheng
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture and Rural Affairs, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, 100081, Beijing, China
| | - Aiai Zhang
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture and Rural Affairs, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, 100081, Beijing, China
| | - Yuhua He
- Henan Key Laboratory of Fruit and Cucurbit Biology, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, China
| | - Changsheng Wang
- National Center for Gene Research, CAS Center for Excellence in Molecular Plant Sciences, Shanghai, 200000, China
| | - Chuanqiang Xu
- Shenyang Agricultural University, College of Horticulture, Shenyang, 110866, China
| | - Benxue Chen
- Design Gollege, Zhoukou Normal University, Zhoukou, 466000, China
| | - Jordi Garcia-Mas
- Centre for Research in Agricultural Genomics CSIC-IRTA-UAB-UB, Barcelona, Spain
- Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Barcelona, Spain
| | - Guangwei Zhao
- Henan Key Laboratory of Fruit and Cucurbit Biology, Zhengzhou Fruit Research Institute, Chinese Academy of Agricultural Sciences, Zhengzhou, 450009, China.
| | - Huaisong Wang
- Key Laboratory of Biology and Genetic Improvement of Horticultural Crops of the Ministry of Agriculture and Rural Affairs, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.
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Zhang Y, He P, Ma X, Yang Z, Pang C, Yu J, Wang G, Friml J, Xiao G. Auxin-mediated statolith production for root gravitropism. THE NEW PHYTOLOGIST 2019; 224:761-774. [PMID: 31111487 DOI: 10.1111/nph.15932] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/11/2019] [Indexed: 05/11/2023]
Abstract
Root gravitropism is one of the most important processes allowing plant adaptation to the land environment. Auxin plays a central role in mediating root gravitropism, but how auxin contributes to gravitational perception and the subsequent response are still unclear. Here, we showed that the local auxin maximum/gradient within the root apex, which is generated by the PIN directional auxin transporters, regulates the expression of three key starch granule synthesis genes, SS4, PGM and ADG1, which in turn influence the accumulation of starch granules that serve as a statolith perceiving gravity. Moreover, using the cvxIAA-ccvTIR1 system, we also showed that TIR1-mediated auxin signaling is required for starch granule formation and gravitropic response within root tips. In addition, axr3 mutants showed reduced auxin-mediated starch granule accumulation and disruption of gravitropism within the root apex. Our results indicate that auxin-mediated statolith production relies on the TIR1/AFB-AXR3-mediated auxin signaling pathway. In summary, we propose a dual role for auxin in gravitropism: the regulation of both gravity perception and response.
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Affiliation(s)
- Yuzhou Zhang
- Key Laboratory of the Ministry of Education for Medicinal Plant Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in the Northwest of China, College of Life Sciences, Shaanxi Normal University, No. 620, West Chang'an Avenue, Chang'an District, Xi'an, 710119, China
- Institute of Science and Technology (IST) Austria, 3400, Klosterneuburg, Austria
| | - Peng He
- Key Laboratory of the Ministry of Education for Medicinal Plant Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in the Northwest of China, College of Life Sciences, Shaanxi Normal University, No. 620, West Chang'an Avenue, Chang'an District, Xi'an, 710119, China
| | - Xiongfeng Ma
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, No.100 Science Avenue, Zhengzhou, 450001, China
- Cotton Research Institute, Chinese Academy of Agricultural Sciences, No. 38 Yellow River Avenue, Anyang, 455000, China
| | - Zuoren Yang
- Zhengzhou Research Base, State Key Laboratory of Cotton Biology, Zhengzhou University, No.100 Science Avenue, Zhengzhou, 450001, China
- Cotton Research Institute, Chinese Academy of Agricultural Sciences, No. 38 Yellow River Avenue, Anyang, 455000, China
| | - Chaoyou Pang
- Cotton Research Institute, Chinese Academy of Agricultural Sciences, No. 38 Yellow River Avenue, Anyang, 455000, China
| | - Jianing Yu
- Key Laboratory of the Ministry of Education for Medicinal Plant Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in the Northwest of China, College of Life Sciences, Shaanxi Normal University, No. 620, West Chang'an Avenue, Chang'an District, Xi'an, 710119, China
| | - Guodong Wang
- Key Laboratory of the Ministry of Education for Medicinal Plant Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in the Northwest of China, College of Life Sciences, Shaanxi Normal University, No. 620, West Chang'an Avenue, Chang'an District, Xi'an, 710119, China
| | - Jiří Friml
- Institute of Science and Technology (IST) Austria, 3400, Klosterneuburg, Austria
| | - Guanghui Xiao
- Key Laboratory of the Ministry of Education for Medicinal Plant Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in the Northwest of China, College of Life Sciences, Shaanxi Normal University, No. 620, West Chang'an Avenue, Chang'an District, Xi'an, 710119, China
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Dinesh DC, Kovermann M, Gopalswamy M, Hellmuth A, Calderón Villalobos LIA, Lilie H, Balbach J, Abel S. Solution structure of the PsIAA4 oligomerization domain reveals interaction modes for transcription factors in early auxin response. Proc Natl Acad Sci U S A 2015; 112:6230-5. [PMID: 25918389 PMCID: PMC4434759 DOI: 10.1073/pnas.1424077112] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The plant hormone auxin activates primary response genes by facilitating proteolytic removal of auxin/indole-3-acetic acid (AUX/IAA)-inducible repressors, which directly bind to transcriptional auxin response factors (ARF). Most AUX/IAA and ARF proteins share highly conserved C-termini mediating homotypic and heterotypic interactions within and between both protein families. The high-resolution NMR structure of C-terminal domains III and IV of the AUX/IAA protein PsIAA4 from pea (Pisum sativum) revealed a globular ubiquitin-like β-grasp fold with homologies to the Phox and Bem1p (PB1) domain. The PB1 domain of wild-type PsIAA4 features two distinct surface patches of oppositely charged amino acid residues, mediating front-to-back multimerization via electrostatic interactions. Mutations of conserved basic or acidic residues on either face suppressed PsIAA4 PB1 homo-oligomerization in vitro and confirmed directional interaction of full-length PsIAA4 in vivo (yeast two-hybrid system). Mixing of oppositely mutated PsIAA4 PB1 monomers enabled NMR mapping of the negatively charged interface of the reconstituted PsIAA4 PB1 homodimer variant, whose stoichiometry (1:1) and equilibrium binding constant (KD ∼ 6.4 μM) were determined by isothermal titration calorimetry. In silico protein-protein docking studies based on NMR and yeast interaction data derived a model of the PsIAA4 PB1 homodimer, which is comparable with other PB1 domain dimers, but indicated considerable differences between the homodimeric interfaces of AUX/IAA and ARF PB1 domains. Our study provides an impetus for elucidating the molecular determinants that confer specificity to complex protein-protein interaction circuits between members of the two central families of transcription factors important to the regulation of auxin-responsive gene expression.
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Affiliation(s)
| | - Michael Kovermann
- Institute of Physics, Biophysics and Mitteldeutsches Zentrum für Struktur und Dynamik der Proteine
| | - Mohanraj Gopalswamy
- Institute of Physics, Biophysics and Mitteldeutsches Zentrum für Struktur und Dynamik der Proteine
| | - Antje Hellmuth
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry, D-06120 Halle, Germany
| | | | - Hauke Lilie
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany; and
| | - Jochen Balbach
- Institute of Physics, Biophysics and Mitteldeutsches Zentrum für Struktur und Dynamik der Proteine;
| | - Steffen Abel
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry, D-06120 Halle, Germany; Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, D-06120 Halle, Germany; and Department of Plant Sciences, University of California, Davis, CA 95616
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7
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Larsson E, Sitbon F, von Arnold S. Polar auxin transport controls suspensor fate. PLANT SIGNALING & BEHAVIOR 2008; 3:469-70. [PMID: 19704488 PMCID: PMC2634432 DOI: 10.4161/psb.3.7.5676] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Accepted: 01/31/2008] [Indexed: 05/19/2023]
Abstract
Polar auxin transport is critical for normal embryo development in angiosperms. It has been proposed that auxin accumulates dynamically at specific positions, which in early Arabidopsis embryos correlates with developmental decisions such as specification of the apical cell lineage, specification of the hypophysis, and differentiation of the two cotyledons. In conifers, pattern formation during embryo development is different, and includes a free nuclear stage, nondividing suspensor cells, presence of tube cells, lack of hypophysis and formation of a crown of cotyledons surrounding the shoot apical meristem. We have recently shown that polar auxin transport is important for normal embryo development also in conifers. Here we suggest a model where auxin is transported from the suspensor cells to the embryonal mass during early embryogeny in conifers. This transport is essential for the developmental decisions of the tube cells and the suspensor, and affects both the amount of programmed cell death and the embryo patterning.
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Affiliation(s)
- Emma Larsson
- Department of Plant Biology and Forest Genetics; Swedish University of Agricultural Sciences; Uppsala, Sweden
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Abstract
The phytohormone auxin is a key factor in plant growth and development. Forward and reverse genetic strategies have identified important molecular components in auxin perception, signaling, and transport. These advances resulted in the identification of some of the underlying regulatory mechanisms as well as the emergence of functional frameworks for auxin action. This review focuses on the feedback loops that form an integrative part of these regulatory mechanisms.
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Affiliation(s)
- René Benjamins
- Department of Biology, Faculty of Science, Utrecht University, 3584 CH Utrecht, The Netherlands.
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9
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Gu R, Zhao L, Zhang Y, Chen X, Bao J, Zhao J, Wang Z, Fu J, Liu T, Wang J, Wang G. Isolation of a maize beta-glucosidase gene promoter and characterization of its activity in transgenic tobacco. PLANT CELL REPORTS 2006; 25:1157-65. [PMID: 16770627 DOI: 10.1007/s00299-006-0177-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Revised: 04/11/2006] [Accepted: 05/02/2006] [Indexed: 05/10/2023]
Abstract
The beta-glucosidase gene of maize (ZmGLU1) was suggested to hydrolyze cytokinin-conjugate and release free cytokinin during plant growth and development. A clone containing the upstream region of ZmGLU1 was isolated and sequenced from a maize genomic library. The full-length ZmGLU1 promoter and a series of its 5' deletions were fused to the beta-glucuronidase (GUS) reporter gene and transferred into tobacco. The GUS activity of transgenic plants was assayed at various developmental stages. The results showed that ZmGLU1 promoter-driven GUS gene had the highest expression level in the roots and that the expression of GUS gene declined during seed maturation and down to the lowest level in mature seeds. The ZmGLU1 promoter-driven GUS expression increased during seed germination, reaching a peak on day 11. The results also showed that this promoter could be inhibited by 6-BA, trans-zeatin, and NAA, but was not affected by GA(3), ABA, SA, cold, salt, drought, and submergence treatments. The histochemical staining revealed that GUS activity was located in vigorous cell division zones with dominant staining associated with vascular tissues. Deletion analysis showed that the promoter contained a putative leaf-specific and stem-specific negative regulative element and two putative enhancers.
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Affiliation(s)
- Riliang Gu
- State Key Laboratory for Agrobiotechnology and National Center for Maize Improvement, China Agricultural University, Beijing, 100094, China
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Schwechheimer C, Schwager K. Regulated proteolysis and plant development. PLANT CELL REPORTS 2004; 23:353-364. [PMID: 15365760 DOI: 10.1007/s00299-004-0858-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2004] [Revised: 07/22/2004] [Accepted: 07/22/2004] [Indexed: 05/24/2023]
Abstract
Eukaryotes use the ubiquitin-proteasome system to control the abundance of regulatory proteins such as cell-cycle proteins and transcription factors. Over 5% of the Arabidopsis genome encodes for proteins with an apparent functional homology to components of the ubiquitin-proteasome system. This suggests that ubiquitin-mediated proteolysis has a major role in plant growth and development. Consistent with this notion, various processes, including most phytohormone responses and photomorphogenesis, have already been shown to require protein degradation in one way or another. In this review, we provide an overview of the plant ubiquitin-proteasome system and its role during Arabidopsis development. Since we consider auxin response and photomorphogenesis as particularly instructive examples, these processes are reviewed in greater detail.
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Affiliation(s)
- Claus Schwechheimer
- Developmental Genetics, Centre for Plant Molecular Biology, Auf der Morgenstelle 5, 72076, Tübingen, Germany.
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11
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Moyle R, Schrader J, Stenberg A, Olsson O, Saxena S, Sandberg G, Bhalerao RP. Environmental and auxin regulation of wood formation involves members of the Aux/IAA gene family in hybrid aspen. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2002; 31:675-685. [PMID: 12220260 DOI: 10.1046/j.1365-313x.2002.01386.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Indole acetic acid (IAA/auxin) profoundly affects wood formation but the molecular mechanism of auxin action in this process remains poorly understood. We have cloned cDNAs for eight members of the Aux/IAA gene family from hybrid aspen (Populus tremula L. x Populus tremuloides Michx.) that encode potential mediators of the auxin signal transduction pathway. These genes designated as PttIAA1-PttIAA8 are auxin inducible but differ in their requirement of de novo protein synthesis for auxin induction. The auxin induction of the PttIAA genes is also developmentally controlled as evidenced by the loss of their auxin inducibility during leaf maturation. The PttIAA genes are differentially expressed in the cell types of a developmental gradient comprising the wood-forming tissues. Interestingly, the expression of the PttIAA genes is downregulated during transition of the active cambium into dormancy, a process in which meristematic cells of the cambium lose their sensitivity to auxin. Auxin-regulated developmental reprogramming of wood formation during the induction of tension wood is accompanied by changes in the expression of PttIAA genes. The distinct tissue-specific expression patterns of the auxin inducible PttIAA genes in the cambial region together with the change in expression during dormancy transition and tension wood formation suggest a role for these genes in mediating cambial responses to auxin and xylem development.
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Affiliation(s)
- Richard Moyle
- Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Department of Forest Genetics and Plant Physiology, 90183 Umeå, Sweden
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Mizuno H, Kobayashi A, Fujii N, Yamashita M, Takahashi H. Hydrotropic response and expression pattern of auxin-inducible gene, CS-IAA1, in the primary roots of clinorotated cucumber seedlings. PLANT & CELL PHYSIOLOGY 2002; 43:793-801. [PMID: 12154142 DOI: 10.1093/pcp/pcf093] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Primary roots of cucumber seedlings showed positive hydrotropism when exposed to a moisture gradient and rotated on a two-axis clinostat. To examine the role of auxin in the differential growth of the hydrotropically responding roots, we first examined the expression of auxin-inducible genes, CS-AUX/IAAs, in cucumber roots. After auxin starvation, mRNA levels of CS-IAA1 and CS-IAA3 decreased in the roots. Applying auxin to the auxin-starved roots resulted in accumulation of CS-IAA1 and CS-IAA3 mRNA. The level of expression of these genes increased when the auxin concentration was increased. CS-IAA1 mRNA accumulated in response to 10(-8) M auxin, and the level increased further, depending on the dose. Auxin starvation did not result in a decrease in the level of CS-IAA2 mRNA; however, adding exogenous auxin at concentrations higher than 10(-7) M increased its accumulation. In the primary roots responding hydrotropically or gravitropically, CS-IAA1 expression was greater on the concave side of the curving roots than on the convex side. The difference could be detected 30 min following stimulation by gravity or a moisture gradient, and that difference increased with time. These results support the idea that asymmetry of localization of auxin is associated with differential growth in hydrotropically responding roots.
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Affiliation(s)
- Hidetoshi Mizuno
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, 980-8577 Japan
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Coenen C, Bierfreund N, Lüthen H, Neuhaus G. Developmental regulation of H+-ATPase-dependent auxin responses in the diageotropica mutant of tomato (Lycopersicon esculentum). PHYSIOLOGIA PLANTARUM 2002; 114:461-471. [PMID: 12060269 DOI: 10.1034/j.1399-3054.2002.1140316.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Rapid auxin effects on H+ pumping across the plasma membrane precede auxin-induced elongation growth of hypocotyls and swelling of guard cells, as well as auxin inhibition of root growth. To investigate whether auxin-signalling mechanisms in such diverse cell types are similar, we characterized these responses in various tissues of the diageotropica (dgt) mutant of tomato (Lycopersicon esculentum Mill.). Abraded hypocotyl segments of 4-day-old, etiolated dgt seedlings showed an impaired H+ secretion response to applied auxin. mRNA levels for two PM H+-ATPase isoforms, LHA2 and LHA4, were not reduced in dgt hypocotyl segments as compared to wild-type segments, suggesting that the dgt mutation does not affect H+ secretion by reducing the transcription of major PM H+-ATPase genes. The dgt mutation also disrupted auxin inhibition of growth and H+ secretion in roots of 4-day-old dgt seedlings. However, immediately after germination, dgt seedling roots responded to auxin with a near-normal inhibition of growth. In addition, stomata in epidermal peels from 2-week-old dgt cotyledons demonstrated normal auxin-induced opening. We conclude that an intact DGT gene product is required for auxin-induced H+ secretion in tomato hypocotyl segments and for auxin inhibition of H+ secretion in roots of older seedlings, but that a DGT-independent pathway for auxin responses exists in young root tips and in guard cells. A developmentally controlled switch from DGT-independent to DGT-dependent auxin signalling appears to take place in root tips within 2 days after germination.
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Affiliation(s)
- Catharina Coenen
- Biology Department, Allegheny College, Meadville, PA 16335, USA Institut für Biologie II - Zellbiologie, Albert-Ludwigs Universität Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany Institut für Allgemeine Botanik, Universität Hamburg, Ohnhorststrasse 18, D-22609 Hamburg, Germany Corresponding author, e-mail:
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Colón-Carmona A, Chen DL, Yeh KC, Abel S. Aux/IAA proteins are phosphorylated by phytochrome in vitro. PLANT PHYSIOLOGY 2000; 124:1728-38. [PMID: 11115889 PMCID: PMC59870 DOI: 10.1104/pp.124.4.1728] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2000] [Revised: 09/18/2000] [Accepted: 09/25/2000] [Indexed: 05/18/2023]
Abstract
Auxin/indole-3-acetic acid (Aux/IAA) genes encode short-lived transcription factors that are induced as a primary response to the plant growth hormone IAA or auxin. Gain-of-function mutations in Arabidopsis genes, SHY2/IAA3, AXR3/IAA17, and AXR2/IAA7 cause pleiotropic phenotypes consistent with enhanced auxin responses, possibly by increasing Aux/IAA protein stability. Semidominant mutations shy2-1D, shy2-2, axr3-1, and axr2-1 induce ectopic light responses in dark-grown seedlings. Because genetic studies suggest that the shy2-1D and shy2-2 mutations bypass phytochrome requirement for certain aspects of photomorphogenesis, we tested whether SHY2/IAA3 and related Aux/IAA proteins interact directly with phytochrome and whether they are substrates for its protein kinase activity. Here we show that recombinant Aux/IAA proteins from Arabidopsis and pea (Pisum sativum) interact in vitro with recombinant phytochrome A from oat (Avena sativa). We further show that recombinant SHY2/IAA3, AXR3/IAA17, IAA1, IAA9, and Ps-IAA4 are phosphorylated by recombinant oat phytochrome A in vitro. Deletion analysis of Ps-IAA4 indicates that phytochrome A phosphorylation occurs on the N-terminal half of the protein. Metabolic labeling and immunoprecipitation studies with affinity-purified antibodies to IAA3 demonstrate increased in vivo steady-state levels of mutant IAA3 in shy2-2 plants and phosphorylation of the SHY2-2 protein in vivo. Phytochrome-dependent phosphorylation of Aux/IAA proteins is proposed to provide one molecular mechanism for integrating auxin and light signaling in plant development.
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Affiliation(s)
- A Colón-Carmona
- Department of Vegetable Crops, University of California, One Shields Avenue, Davis, California 95616, USA
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Nagpal P, Walker LM, Young JC, Sonawala A, Timpte C, Estelle M, Reed JW. AXR2 encodes a member of the Aux/IAA protein family. PLANT PHYSIOLOGY 2000; 123:563-74. [PMID: 10859186 PMCID: PMC59024 DOI: 10.1104/pp.123.2.563] [Citation(s) in RCA: 176] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/1999] [Accepted: 02/26/2000] [Indexed: 05/17/2023]
Abstract
The dominant gain-of-function axr2-1 mutation of Arabidopsis causes agravitropic root and shoot growth, a short hypocotyl and stem, and auxin-resistant root growth. We have cloned the AXR2 gene using a map-based approach, and find that it is the same as IAA7, a member of the IAA (indole-3-acetic acid) family of auxin-inducible genes. The axr2-1 mutation changes a single amino acid in conserved domain II of AXR2/IAA7. We isolated loss-of-function mutations in AXR2/IAA7 as intragenic suppressors of axr2-1 or in a screen for insertion mutations in IAA genes. A null mutant has a slightly longer hypocotyl than wild-type plants, indicating that AXR2/IAA7 controls development in light-grown seedlings, perhaps in concert with other gene products. Dark-grown axr2-1 mutant plants have short hypocotyls and make leaves, suggesting that activation of AXR2/IAA7 is sufficient to induce morphological responses normally elicited by light. Previously described semidominant mutations in two other Arabidopsis IAA genes cause some of the same phenotypes as axr2-1, but also cause distinct phenotypes. These results illustrate functional differences among members of the Arabidopsis IAA gene family.
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Affiliation(s)
- P Nagpal
- Department of Biology, University of North Carolina at Chapel Hill, 27599-3280, USA
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Kim J, Harter K, Theologis A. Protein-protein interactions among the Aux/IAA proteins. Proc Natl Acad Sci U S A 1997; 94:11786-91. [PMID: 9342315 PMCID: PMC23574 DOI: 10.1073/pnas.94.22.11786] [Citation(s) in RCA: 365] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/1997] [Accepted: 08/20/1997] [Indexed: 02/05/2023] Open
Abstract
The plant hormone indoleacetic acid (IAA) transcriptionally activates early genes in plants. The Aux/IAA family of early genes encodes proteins that are short-lived and nuclear-localized. They also contain a putative prokaryotic betaalphaalpha DNA binding motif whose formation requires protein dimerization. Here, we show that the pea PS-IAA4 and Arabidopsis IAA1 and IAA2 proteins perform homo- and heterotypic interactions in yeast using the two-hybrid system. Gel-filtration chromatography and chemical cross-linking experiments demonstrate that the PS-IAA4 and IAA1 proteins interact to form homodimers in vitro. Deletion analysis of PS-IAA4 indicates that the betaalphaalpha containing acidic C terminus of the protein is necessary for homotypic interactions in the yeast two-hybrid system. Screening an Arabidopsis lambda-ACT cDNA library using IAA1 as a bait reveals heterotypic interactions of IAA1 with known and newly discovered members of the Arabidopsis Aux/IAA gene family. The new member IAA24 has similarity to ARF1, a transcription factor that binds to an auxin response element. Combinatorial interactions among the various members of the Aux/IAA gene family may regulate a variety of late genes as well as serve as autoregulators of early auxin-regulated gene expression. These interactions provide a molecular basis for the developmental and tissue-specific manner of auxin action.
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Affiliation(s)
- J Kim
- Plant Gene Expression Center, 800 Buchanan Street, Albany, CA 94710, USA
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Abstract
Genes induced by the plant hormone auxin are probably involved in the execution of vital cellular functions and developmental processes. Experimental approaches designed to elucidate the molecular mechanisms of auxin action have focused on auxin perception, genetic dissection of the signaling apparatus and specific gene activation. Auxin-responsive promoter elements of early genes provide molecular tools for probing auxin signaling in reverse. Functional analysis of several auxin-specific promoters of unrelated early genes suggests combinatorial utilization of both conserved and variable elements. These elements are arranged into autonomous domains and the combination of such modules generates uniquely composed promoters. Modular promoters allow for auxin-mediated transcriptional responses to be revealed in a tissue- and development-specific manner.
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Affiliation(s)
- S Abel
- Plant Gene Expression Center, Albany, CA 94710, USA
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