> Lateral branching is a crucial agronomic trait that impacts crop yield.
> In tomato (Solanum lycopersicum), excessive lateral branching is unfavorable and results in substantial labor and management costs.
> Therefore, optimizing lateral branching is a primary objective in tomato breeding.
> Although many genes related to lateral branching have been reported in tomato, the molecular mechanism underlying their network remains elusive.
> In this study, we found that the expression profile of a WRKY gene, WRKY-B (for WRKY-BRANCING), was associated with the auxin-dependent axillary bud development process.
> Wrky-b mutants generated by the CRISPR/Cas9 editing system presented fewer lateral branches, while WRKY-B overexpression lines presented more lateral branches than did wild-type plants.
> Furthermore, WRKY-B can directly target the well-known branching gene BLIND (BL) and the auxin efflux carrier gene PIN4 to activate their expression.
> Both the bl and pin4 mutants exhibited reduced lateral branching, similar to the wrky-b mutant.
> The IAA contents in the axillary buds of the wrky-b, bl, and pin4 mutant plants were significantly higher than those in the wild-type plants.
> In addition, WRKY-B can also directly target the AUX/IAA gene IAA15 and repress its expression.
> In summary, WRKY-B works upstream of BL, PIN4, and IAA15 to regulate the development of lateral branches in tomato.
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The tomato WRKY-B transcription factor modulates lateral branching by targeting BLIND, PIN4, and IAA15 – July 2024
https://academic.oup.com/hr/article/11/9/uhae193/7712258
> Abstract
> Lateral branching is a crucial agronomic trait that impacts crop yield.
> In tomato (Solanum lycopersicum), excessive lateral branching is unfavorable and results in substantial labor and management costs.
> Therefore, optimizing lateral branching is a primary objective in tomato breeding.
> Although many genes related to lateral branching have been reported in tomato, the molecular mechanism underlying their network remains elusive.
> In this study, we found that the expression profile of a WRKY gene, WRKY-B (for WRKY-BRANCING), was associated with the auxin-dependent axillary bud development process.
> Wrky-b mutants generated by the CRISPR/Cas9 editing system presented fewer lateral branches, while WRKY-B overexpression lines presented more lateral branches than did wild-type plants.
> Furthermore, WRKY-B can directly target the well-known branching gene BLIND (BL) and the auxin efflux carrier gene PIN4 to activate their expression.
> Both the bl and pin4 mutants exhibited reduced lateral branching, similar to the wrky-b mutant.
> The IAA contents in the axillary buds of the wrky-b, bl, and pin4 mutant plants were significantly higher than those in the wild-type plants.
> In addition, WRKY-B can also directly target the AUX/IAA gene IAA15 and repress its expression.
> In summary, WRKY-B works upstream of BL, PIN4, and IAA15 to regulate the development of lateral branches in tomato.