Multiple roles of the transcription factor AtMYBR1/AtMYB44 in ABA signaling, stress responses, and leaf senescence

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DOIResolve DOI: http://doi.org/10.1186/1471-2229-13-192
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TypeArticle
Journal titleBMC Plant Biology
ISSN1471-2229
Volume13
Article number192
Pagese192-1e192-19; # of pages: 19
SubjectArabidopsis thaliana; ABA; Drought stress; transcription factor; PYL8; Senescence
AbstractBackground: The transcription factor AtMYBR1 (MYB44) is a member of the MYB family of transcription factors and is expressed throughout the plant life cycle and especially in senescing and wounded leaves. It has previously been shown to be involved in responses to abiotic stress and is regulated by phosphorylation.Results: When MYBR1 was over-expressed under the control of the constitutive 35S promoter in Arabidopsis thaliana (OxMYBR1), leaf senescence was delayed. In contrast loss-of-function mybr1 plants showed more rapid chlorophyll loss and senescence. The MYBR1 promoter strongly drove β-GLUCURONIDASE reporter gene expression in tissues immediately after wounding and many wounding/pathogenesis genes were downregulated in OxMYBR1. OxMYBR1 plants were more susceptible to injury under water stress than wildtype, which was correlated with suppression of many ABA inducible stress genes in OxMYBR1. Conversely, mybr1 plants were more tolerant of water stress and exhibited reduced rates of water loss from leaves. MYBR1 physically interacted with ABA receptor PYR1-LIKE8 (PYL8) suggesting a direct involvement of MYBR1 in early ABA signaling. MYBR1 appears to exhibit partially redundant functions with AtMYBR2 (MYB77) and double mybr1 X mybr2 mutants exhibited stronger senescence and stress related phenotypes than single mybr1 and mybr2 mutants.Conclusions: MYBR1 is a negative regulator of ABA, stress, wounding responses and blocks senescence. It appears to have a homeostatic function to maintain growth processes in the event of physical damage or stress.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC); Aquatic and Crop Resource Development
Peer reviewedYes
NRC numberNRC-ACRD-50185
NPARC number21270959
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Record identifier259ff518-4322-466e-9584-f86ae16e0ff7
Record created2014-02-18
Record modified2016-05-09
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