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Badet T, Léger O, Barascud M, Voisin D, Sadon P, Vincent R, Le Ru A, Balagué C, Roby D, Raffaele S. Expression polymorphism at the ARPC4 locus links the actin cytoskeleton with quantitative disease resistance to Sclerotinia sclerotiorum in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2019; 222:480-496. [PMID: 30393937 DOI: 10.1111/nph.15580] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 10/25/2018] [Indexed: 06/08/2023]
Abstract
Quantitative disease resistance (QDR) is a form of plant immunity widespread in nature, and the only one active against broad host range fungal pathogens. The genetic determinants of QDR are complex and largely unknown, and are thought to rely partly on genes controlling plant morphology and development. We used genome-wide association mapping in Arabidopsis thaliana to identify ARPC4 as associated with QDR against the necrotrophic fungal pathogen Sclerotinia sclerotiorum. Mutants impaired in ARPC4 showed enhanced susceptibility to S. sclerotiorum, defects in the structure of the actin filaments and in their responsiveness to S. sclerotiorum. Disruption of ARPC4 also alters callose deposition and the expression of defense-related genes upon S. sclerotiorum infection. Analysis of ARPC4 diversity in A. thaliana identified one haplotype (ARPC4R ) showing a c. 1 kbp insertion in ARPC4 regulatory region and associated with higher level of QDR. Accessions from the ARPC4R haplotype showed enhanced ARPC4 expression upon S. sclerotiorum challenge, indicating that polymorphisms in ARPC4 regulatory region are associated with enhanced QDR. This work identifies a novel actor of plant QDR against a fungal pathogen and provides a prime example of genetic mechanisms leading to the recruitment of cell morphology processes in plant immunity.
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Affiliation(s)
- Thomas Badet
- LIPM, Université de Toulouse, INRA, CNRS, 31326, Castanet-Tolosan, France
| | - Ophélie Léger
- LIPM, Université de Toulouse, INRA, CNRS, 31326, Castanet-Tolosan, France
| | - Marielle Barascud
- LIPM, Université de Toulouse, INRA, CNRS, 31326, Castanet-Tolosan, France
| | - Derry Voisin
- LIPM, Université de Toulouse, INRA, CNRS, 31326, Castanet-Tolosan, France
| | - Pierre Sadon
- LIPM, Université de Toulouse, INRA, CNRS, 31326, Castanet-Tolosan, France
| | - Remy Vincent
- LIPM, Université de Toulouse, INRA, CNRS, 31326, Castanet-Tolosan, France
| | - Aurélie Le Ru
- Plateforme Imagerie, Pôle de Biotechnologie Végétale, Fédération de Recherche 3450, 31326, Castanet-Tolosan, France
| | - Claudine Balagué
- LIPM, Université de Toulouse, INRA, CNRS, 31326, Castanet-Tolosan, France
| | - Dominique Roby
- LIPM, Université de Toulouse, INRA, CNRS, 31326, Castanet-Tolosan, France
| | - Sylvain Raffaele
- LIPM, Université de Toulouse, INRA, CNRS, 31326, Castanet-Tolosan, France
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Iorizzo M, Cavagnaro PF, Bostan H, Zhao Y, Zhang J, Simon PW. A Cluster of MYB Transcription Factors Regulates Anthocyanin Biosynthesis in Carrot ( Daucus carota L.) Root and Petiole. FRONTIERS IN PLANT SCIENCE 2019; 9:1927. [PMID: 30693006 PMCID: PMC6339893 DOI: 10.3389/fpls.2018.01927] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 12/11/2018] [Indexed: 05/24/2023]
Abstract
Purple carrots can accumulate large quantities of anthocyanins in their roots and -in some genetic backgrounds- petioles, and therefore they represent an excellent dietary source of antioxidant phytonutrients. In a previous study, using linkage analysis in a carrot F2 mapping population segregating for root and petiole anthocyanin pigmentation, we identified a region in chromosome 3 with co-localized QTL for all anthocyanin pigments of the carrot root, whereas petiole pigmentation segregated as a single dominant gene and mapped to one of these "root pigmentation" regions conditioning anthocyanin biosynthesis. In the present study, we performed fine mapping combined with gene expression analyses (RNA-Seq and RT-qPCR) to identify candidate genes controlling anthocyanin pigmentation in the carrot root and petiole. Fine mapping was performed in four carrot populations with different genetic backgrounds and patterns of pigmentation. The regions controlling root and petiole pigmentation in chromosome 3 were delimited to 541 and 535 kb, respectively. Genome wide prediction of transcription factor families known to regulate the anthocyanin biosynthetic pathway coupled with orthologous and phylogenetic analyses enabled the identification of a cluster of six MYB transcription factors, denominated DcMYB6 to DcMYB11, associated with the regulation of anthocyanin biosynthesis. No anthocyanin biosynthetic genes were present in this region. Comparative transcriptome analysis indicated that upregulation of DcMYB7 was always associated with anthocyanin pigmentation in both root and petiole tissues, whereas DcMYB11 was only upregulated with pigmentation in petioles. In the petiole, the level of expression of DcMYB11 was higher than DcMYB7. DcMYB6, a gene previously suggested as a key regulator of carrot anthocyanin biosynthesis, was not consistently associated with pigmentation in either tissue. These results strongly suggest that DcMYB7 is a candidate gene for root anthocyanin pigmentation in all the genetic backgrounds included in this study. DcMYB11 is a candidate gene for petiole pigmentation in all the purple carrot sources in this study. Since DcMYB7 is co-expressed with DcMYB11 in purple petioles, the latter gene may act also as a co-regulator of anthocyanin pigmentation in the petioles. This study provides linkage-mapping and functional evidence for the candidacy of these genes for the regulation of carrot anthocyanin biosynthesis.
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Affiliation(s)
- Massimo Iorizzo
- Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, United States
- Department of Horticultural Science, North Carolina State University, Raleigh, NC, United States
| | - Pablo F. Cavagnaro
- National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
- Estación Experimental Agropecuaria La Consulta, Instituto Nacional de Tecnología Agropecuaria (INTA), Mendoza, Argentina
- Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Mendoza, Argentina
| | - Hamed Bostan
- Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, United States
| | - Yunyang Zhao
- Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, United States
| | - Jianhui Zhang
- Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, United States
| | - Philipp W. Simon
- Department of Horticulture, University of Wisconsin–Madison, Madison, WI, United States
- Vegetable Crops Research Unit, United States Department of Agriculture–Agricultural Research Service, Madison, WI, United States
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