Interplay of auxin and jasmonates in tomato gynoecia development and fruit set

植物的成功繁殖取决于花器官发育、受精和坐果的紧密协调。植物激素生长素和茉莉酸（JA）在这些过程的时间和协调中发挥重要作用。我们的初步工作表明，生长素和JA相互作用的调节雌蕊发育和开始坐果受精。它还鉴定了受生长素和JA调节的转录因子SlMYB 21和SlMYB 24。在项目的第一阶段，我们确定了生长素反应因子SlARF 8A和SlARF 8B作为雌蕊发育和座果的中心调节因子。我们发现，Slarf 8a Slarf 8b双突变体的花柱和柱头发育受损，产生无籽果实独立的受精。此外，Slarf 8a Slarf 8b突变体植物的雌蕊花具有降低的JA水平以及SlMYB 21和SlMYB 24表达。我们已经产生了包含Slmyb 24和Slmyb 21的敲除的突变体Slmyb 24双突变体植物，并发现Slmyb 24显著增强了Slmyb 21在雌蕊发育和坐果方面的表型。这些结果表明SlARF 8、SlMYB 21/24和JA相互作用调节花和果实发育。在更新的建议，我们的目标是解决以下假设：（i）SlARF 8促进JA生产，可能通过激活SlMYB 21，和SlMYB 21抑制SlARF 8的表达;（ii）SlMYB 21和SlMYB 24共同作用，以调节花的发育和过渡到坐果;和（iii）SlARF 8，SlMYB 21/24和JA柱头发育的中央调节器。我们将通过研究SlARF 8，SlMYB 21/24和JA在雌蕊发育，特别是柱头发育和坐果中的遗传和分子相互作用来验证这些假设。我们将：1.通过产生和表征双突变体和三突变体来阐明SlMYB 21和SlARF之间的调控相互作用。2.表征SlMYB 21和SlMYB 24两者的功能同时丧失的影响。3.描述野生型和突变型植物的柱头发育和基因表达。该研究有望为MYB和ARF在番茄生殖中的协调功能提供见解，并将阐明生长素和JA在番茄生殖调控中的串扰。

Successful plant reproduction depends on tight coordination of flower-organ development, fertilization and fruit set. The plant hormones auxin and jasmonic acid (JA) play important roles in the timing and coordination of these processes. Our preliminary work suggested that auxin and JA interact in the regulation of gynoecia development and of the initiation of fruit set in response to fertilization. It also identified the transcription factors SlMYB21 and SlMYB24 as regulated by both auxin and JA. In the first period of the project, we identified the auxin-response factors SlARF8A and SlARF8B as central regulators of gynoecia development and fruit set. We found that Slarf8a Slarf8b double mutants are impaired in style and stigma development and produce seedless fruits independently of fertilization. Furthermore, gynoecia of Slarf8a Slarf8b mutant plants have reduced JA levels as well as SlMYB21 and SlMYB24 expression. We have generated mutants harboring a knockout of SlMYB24 and Slmyb21 Slmyb24 double mutant plants and found that Slmyb24 substantially enhances the Slmyb21 phenotype with respect to gynoecia development and fruit set. These results suggest that SlARF8, SlMYB21/24 and JA interact to regulate flower and fruit development. In the renewal of the proposal, we aim to address the following hypotheses: (i) SlARF8 promotes JA production, possibly by activating SlMYB21, and SlMYB21 inhibits SlARF8 expression; (ii) SlMYB21 and SlMYB24 act together to regulate flower development and the transition to fruit set; and (iii) SlARF8, SlMYB21/24 and JA are central regulators of stigma development. We will test these hypotheses by examining the genetic and molecular interactions among SlARF8, SlMYB21/24 and JA in gynoecia development and particularly stigma development, and in fruit set. We will: 1. Elucidate the regulatory interaction between SlMYB21 and SlARFs by generation and characterization of double and triple mutants. 2. Characterize the effect of simultaneous loss of function of both SlMYB21 and SlMYB24. 3. Characterize stigma development and gene expression in wild type and mutant plants. The research is expected to provide insights on the coordinated function of MYBs and ARFs in tomato reproduction and will shed light on the crosstalk between auxin and JA in the regulation of reproduction in tomato.