Disrupting auxin-inducible LBD29 expression or expressing an LBD29-SRDX transcriptional repressor phenocopied the lax3 mutant, resulting in delayed lateral root emergence. Yeast one-hybrid screens revealed that the LAX3 promoter is bound by the transcription factor LBD29, which is a direct target for regulation by ARF7. Consistent with model predictions, we report that auxin-inducible LAX3 expression is regulated indirectly by AUXIN RESPONSE FACTOR 7 (ARF7). Multiscale modeling has predicted that this highly focused pattern of expression requires auxin to sequentially induce auxin efflux and influx carriers PIN3 and LAX3, respectively. 2b,c), clearly demonstrating the requirement of RAP2.6L, ERF115, and PLT proteins in wound-induced callus formation. Delimiting LAX3 expression to two adjacent cell files overlying new LRP is crucial to ensure that auxin-regulated cell separation occurs solely along their shared walls. Strikingly, callus formation was significantly compromised in leaf explants of rap2.6l-1/erf113, RAP2.6L-SRDX, erf115, ERF115-SRDX and plt3 plt5 plt7 triple mutant (hereafter referred to as plt3/5/7) loss-of-function mutants (Fig. 35S : ARR1-SRDX transgenic Arabidopsis plants showed phenotypic changes reminiscent of plants with a reduced cytokinin status, such as a strongly reduced leaf size, an enhanced root system, and larger seeds. The auxin-inducible auxin influx carrier LAX3 plays a key role concentrating this signal in cells overlying LRP. In a protoplast test system, ARR1-SRDX suppressed ARR6 : -glucuronidase reporter gene activation by different B-type ARRs. Transgenic plants overexpressing AtMYB20 (AtMYB20-OX) enhanced salt stress tolerance while repression lines (AtMYB20-SRDX) were more vulnerable to NaCl than wild-type plants. By contrast, 35S:CpAG2-SRDX Arabidopsis plants had abnormal carpels and ectopic formation of carpels and stamens in addition to abnormal stamens, but at a lower rate than 35S:CpAG1-SRDX (Fig. LRP emerge through overlying root tissues by inducing auxin-dependent cell separation and hydraulic changes in adjacent cells. Abstract We have characterized the function of a plant R2R3-MYB transcription factor, Arabidopsis thaliana MYB20 (AtMYB20). pYPQ153, pco-dCas9-3X(SRDX) (Plant codon-optimized). (a) Schematic representation of the construct used for expression of the chimeric EIN3 repressors, showing the amino acid sequences of the EAR-motif repression domains from tobacco ERF3 (RD), with the mutated RD domain (RDm), and from Arabidopsis SUPERMAN (SUPRD). The publisher has kindly granted permission to reproduce this abstract on TAIR.Lateral root primordia (LRP) originate from pericycle stem cells located deep within parental root tissues. vectors for highly efficient CRISPR/Cas9-mediated gene knockout in Arabidopsis thaliana. The ethylene-insensitive phenotype of transgenic plants that expressed the chimeric EIN3 repressor. 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. 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. In particular, MYC5-SRDX plants were male sterile, with defects in stamen filament elongation, anther dehiscence, and pollen viability.
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. 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, JAZ1?Jas repressor. We generated a dominant repressor version of the Arabidopsis (Arabidopsis thaliana) response regulator ARR1 (ARR1-SRDX) using chimeric repressor silencing. 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. 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. Arabidopsis thaliana plants deficient in JA-biosynthesis or -signaling are male sterile with defects in stamen and pollen development. Jasmonate hormone (JA) plays critical roles in both plant defense and reproductive development. Title: Male-sterility in Arabidopsis induced by overexpression of a MYC5-SRDX chimeric repressor
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