Cucumber (Cucumis sativus, Cs) tendrils are slender vegetative organs that typically require manual removal to ensure orderly growth during greenhouse cultivation. Here, we identified cucumber tendril-less (tl), a Tnt1 retrotransposon-induced insertion mutant lacking tendrils. Map-based cloning identified the mutated gene, CsaV3_3G003590, which we designated as CsTL, which is homologous to Arabidopsis thaliana LATERAL SUPPRESSOR (AtLAS). Knocking out CsTL repressed tendril formation but did not affect branch initiation, whereas overexpression of CsTL resulted in the formation of two or more tendrils in one leaf axil. Although expression of two cucumber genes regulating tendril formation, Tendril (CsTEN) and Unusual Floral Organs (CsUFO), was significantly decreased in CsTL knockout lines, these two genes were not direct downstream targets of CsTL. Instead, CsTL physically interacted with CsTEN, an interaction that further enhanced CsTEN-mediated expression of CsUFO. In Arabidopsis, the CsTL homolog AtLAS acts upstream of REVOLUTA (REV) to regulate branch initiation. Knocking out cucumber CsREV inhibited branch formation without affecting tendril initiation. Furthermore, genomic regions containing CsTL and AtLAS were not syntenic between the cucumber and Arabidopsis genomes, whereas REV orthologs were found on a shared syntenic block. Our results revealed not only that cucumber CsTL possesses a divergent function in promoting tendril formation but also that CsREV retains its conserved function in shoot branching.

中文翻译：

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GRAS转录因子CsTL调节黄瓜卷须的形成

黄瓜（Cucumis sativus，Cs）卷须是细长的营养器官，通常需要手动去除以确保温室栽培期间的有序生长。在这里，我们鉴定了黄瓜无卷须（tl），一种 Tnt1 逆转录转座子诱导的缺乏卷须的插入突变体。基于图位的克隆鉴定了突变基因 CsaV3_3G003590，我们将其命名为 CsTL，它与拟南芥侧向抑制器 (AtLAS) 同源。敲除 CsTL 会抑制卷须的形成，但不会影响分枝的起始，而 CsTL 的过度表达会导致在一根叶腋中形成两个或多个卷须。尽管调节卷须形成的两个黄瓜基因卷须 (CsTEN) 和异常花器官 (CsUFO) 的表达在 CsTL 敲除系中显着降低，但这两个基因并不是 CsTL 的直接下游靶标。相反，CsTL 与 CsTEN 发生物理相互作用，这种相互作用进一步增强了 CsTEN 介导的 CsUFO 表达。在拟南芥中，CsTL 同源物 AtLAS 在 REVOLUTA (REV) 上游发挥作用，调节分支起始。敲除黄瓜 CsREV 可抑制分枝形成，但不影响卷须的形成。此外，含有 CsTL 和 AtLAS 的基因组区域在黄瓜和拟南芥基因组之间不是同线的，而 REV 直向同源物则在共享同线块上发现。我们的结果不仅表明黄瓜 CsTL 在促进卷须形成方面具有不同的功能，而且 CsREV 在芽分枝中保留了其保守的功能。