The bHLH transcription factor CsPIF4 positively regulates high temperature-induced hypocotyl elongation in cucumber  

作　　者：Jing Nie Yu Jiang Lijun Lv Yuzi Shi Peiyu Chen Qian Zhang Xiaolei Sui 

机构地区：[1]Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops,College of Horticulture,China Agricultural University,Beijing 100193,China

出　　处：《Horticultural Plant Journal》2024年第5期1187-1197,共11页园艺学报（英文版）

基　　金：the China Postdoctoral Science Foundation(Grant No.2021M703530);the National Natural Science Foundation of China(Grant No.31972398).

摘　　要：High temperature-induced hypocotyl elongation is a typical thermomorphogenesis trait that may significantly affect early seedling growth and subsequent crop yield.The ambient temperature and endogenous auxin are two critical factors that regulate hypocotyl growth.However,the mechanism of temperature and auxin integration in horticultural plants remains poorly understood.In this study,the roles of the basic helix-loop-helix transcription factor CsPIF4 in regulating auxin biosynthesis genes and the auxin content in the hypocotyl of cucumber(Cucumis sativus L.)seedlings under high temperature were investigated.qRT-PCR and in situ hybridization analysis revealed that expression of CsPIF4 was enhanced in the epidermis and vascular bundles in the hypocotyl of cucumber seedlings in response to high temperature.qRT-PCR and HPLC analysis showed that CsPIF4 positively regulated transcription of the auxin biosynthesis gene CsYUC8 and the auxin content in the hypocotyl under high temperature(35℃).The CRISPR/Cas9-mediated knockout of CsPIF4 resulted in a shorter hypocotyl compared with that of the wild type,together with decreased expression of CsYUC8 and lower auxin content in response to high temperature.Furthermore,biochemical assays showed that CsPIF4 could bind directly to the G-box motif of the CsYUC8 promoter and thereby activate CsYUC8 expression.These findings provide insight into the molecular mechanism of high temperature-mediated hypocotyl elongation in cucumber.

关 键 词：CUCUMBER Hypocotyl elongation High temperature CsPIF4 AUXIN 

分 类 号：S642.2[农业科学—蔬菜学]