Transcriptional control of local auxin distribution by the CsDFB1-CsPHB module regulates floral organogenesis in cucumber

第一作者：Jing Nie

第一单位：中国农业大学

通讯作者：Xiaolei Sui

 Abstract 

背景回顾：Plant cystatins are cysteine proteinase inhibitors that play key roles in defense responses. 

主要发现：In this work, we describe an unexpected role for the cystatin-like protein DEFORMED FLORAL BUD1 (CsDFB1) as a transcriptional regulator of local auxin distribution in cucumber (Cucumis sativus L.). 

结果1-CsDFB1表达模式：CsDFB1 was strongly expressed in the floral meristems, floral primordia, and vasculature. 

结果2-CsDFB1功能-敲低：RNA interference (RNAi)-mediated silencing of CsDFB1 led to a significantly increased number of floral organs and vascular bundles, together with a pronounced accumulation of auxin. 

结果3-CsDFB1功能-过表达：Conversely, accompanied by a decrease of auxin, overexpression of CsDFB1 resulted in a dramatic reduction in floral organ number and an obvious defect in vascular patterning, as well as organ fusion. 

结果4-CsDFB1互作蛋白CsPHB：CsDFB1 physically interacted with the cucumber ortholog of PHABULOSA (CsPHB), an HD-ZIP III transcription factor whose transcripts exhibit the same pattern as CsDFB1. 

结果5-CsPHB过表达：Overexpression of CsPHB increased auxin accumulation in shoot tips and induced a floral phenotype similar to that of CsDFB1-RNAi lines. 

结果6-CsDFB1-CsPHB模块下游：Furthermore, genetic and biochemical analyses revealed that CsDFB1 impairs CsPHB-mediated transcriptional regulation of the auxin biosynthetic gene YUCCA2 and the auxin efflux carrier PIN-FORMED1, and thus plays a pivotal role in auxin distribution. 

结论：In summary, we propose that the CsDFB1-CsPHB module represents a regulatory pathway for local auxin distribution that governs floral organogenesis and vascular differentiation in cucumber.

 摘 要 

 通讯作者 

**眭晓蕾**

doi: http://www.r57.ss938.com/10.1073/pnas.2023942118

Journal: PNAS

Published date: Feb 23, 2021