College of Horticulture Science, Zhejiang A&F University, Hangzhou, 311300, Zhejiang, China.
Key Laboratory of Quality and Safety Control for Subtropical Fruit and Vegetable, Ministry of Agriculture and Rural Affairs, Hangzhou, 311300, Zhejiang, China.
New Phytol. 2023 Jul;239(1):364-373. doi: 10.1111/nph.18908. Epub 2023 Apr 4.
Tendril is a morphological innovation during plant evolution, which provides the plants to obtain climbing ability. However, the tendril morphogenesis is poorly understood. A novel tendril morphogenesis defective mutant (tmd1) was identified in cucumber. The apical part of tendril was replaced by a leaf blade in tmd1 mutant, and it lost the climbing ability. Map-based cloning, qPCR detection, bioinformatic analysis, yeast one-hybrid assay, electrophoretic mobility shift assay, and luciferase assay were used to explore the molecular mechanism of CsaTMD1 in regulating tendril morphogenesis. CsaUFO was the candidate causal gene, and a fragment deletion within promoter impaired CsaUFO expression in tmd1 mutant. A conserved motif 1, which harbored two putative TCP transcription factor binding sites, was located within this deleted fragment. CsaTEN directly bound the motif 1 and positively regulated CsaUFO, and mutation in motif 1 removed this regulation. Our work shows a CsaTEN-CsaUFO module in regulating tendril morphogenesis, indicating that evolution of tendril in cucumber due to simply drive of CsaUFO by CsaTEN in tendril. Additionally, the conserved motif 1 provides a strategy for engineering tendril-less Cucurbitaceae crops.
卷须是植物进化过程中的一种形态创新，为植物提供了攀援能力。然而，卷须形态发生的机制还不清楚。在黄瓜中鉴定到一个新的卷须形态发生缺陷突变体（tmd1）。tmd1 突变体的卷须顶端部分被叶片取代，丧失了攀援能力。利用图位克隆、qPCR 检测、生物信息学分析、酵母单杂交实验、电泳迁移率变动分析和荧光素酶报告基因实验，研究了 CsaTMD1 调控卷须形态发生的分子机制。CsaUFO 是候选的致病基因，启动子内的一个片段缺失导致 tmd1 突变体中 CsaUFO 表达受损。该缺失片段内包含一个保守的 motif 1，其中含有两个假定的 TCP 转录因子结合位点。CsaTEN 直接结合 motif 1，并正向调控 CsaUFO，而 motif 1 的突变则消除了这种调控。我们的工作表明，CsaTEN-CsaUFO 模块在调控卷须形态发生中起作用，表明黄瓜卷须的进化是由于 CsaTEN 简单地驱动 CsaUFO 引起的。此外，保守的 motif 1 为工程化无卷须葫芦科作物提供了一种策略。
