Plant Male Reproduction Database

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Male-sterility in Arabidopsis induced by overexpression of a MYC5-SRDX chimeric repressor.

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Plant J. 2015 Jan 28. doi: 10.1111/tpj.12776. [Epub ahead of print]

Male-sterility in Arabidopsis induced by overexpression of a MYC5-SRDX chimeric repressor.

Abstract

Jasmonate hormone (JA) plays critical roles in both plant defense and reproductive development. Arabidopsis thaliana plants deficient in JA-biosynthesis or -signaling are male sterile with defects in stamen and pollen development. MYC2, MYC3 and MYC4 are JAZ-interacting bHLH transcription factors, which play a major role in controlling JA responses in vegetative tissue but likely not in reproductive tissue. We found that a closely related transcription factor, MYC5 (bHLH28), was able to induce JAZ promoters that control some of the early JA-responsive genes, in a carrot protoplast expression system. A G-box sequence in the JAZ2 promoter was necessary and sufficient for induction by MYC5 (as it is for MYC2, MYC3 and MYC4), and induction of JAZ genes was repressed by co-expression of a stabilized, JAZ1ΔJas repressor. Two allelic myc5 mutants exhibited no overt phenotype; however, transgenic lines expressing MYC5 fused to an SRDX (SUPERMAN repressive domain X) motif phenocopied mutants defective in JA signaling. In particular, MYC5-SRDX plants were male sterile, with defects in stamen filament elongation, anther dehiscence, and pollen viability. Importantly, expression of MYB21 and other transcription factors required for stamen and pollen maturation was strongly reduced in stamens of MYC5-SRDX plants relative to wild-type. Taken together, these results indicate that MYC5, likely together with other, redundant transcription factors, may be activated by JA signaling to induce expression of MYB21 and components required for male fertility. This article is protected by copyright. All rights reserved.

This article is protected by copyright. All rights reserved.