The transcriptional control of LcIDL1–LcHSL2 complex by LcARF5 integrates auxin and ethylene signaling for litchi fruitlet abscission  

作　　者：Xingshuai Ma Zidi He Ye Yuan Zhijian Liang Hang Zhang Vilde Olsson Lalun Zhuoyi Liu Yanqing Zhang Zhiqiang Huang Yulian Huang Jianguo Li Minglei Zhao 

机构地区：[1]State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources,Guangdong Laboratory for Lingnan Modern Agriculture,Key Laboratory of Biology and Genetic Improvement of Horticultural Crops(South China),Ministry of Agriculture and Rural Affairs,Guangdong Litchi Engineering Research Center,College of Horticulture,South China Agricultural University,Guangzhou 510642,China [2]Dongguan Botanical Garden,Dongguan 523128,China [3]Section for Genetics and Evolutionary Biology,Department of Biosciences,University of Oslo,Blindernveien 31,Oslo 0316,Norway [4]College of Agriculture,Guangxi University,Nanning 530004,China

出　　处：《Journal of Integrative Plant Biology》2024年第6期1206-1226,共21页植物学报（英文版）

基　　金：supported by grants from the National Natural Science Foundation of China(32330092,32202447,32072544 and 32072514);the Natural Science Foundation of Guangdong Province,China(2021B1515120082,2023A1515012661);China Postdoctoral Science Foundation(2022M721209);the Laboratory of Lingnan Modern Agriculture Project(NZ NT2021004);the Guangdong Rural Revitalization Strategic Foundation(20211800400072)。

摘　　要：At the physiological level,the interplay between auxin and ethylene has long been recognized as crucial for the regulation of organ abscission in plants.However,the underlying molecular mechanisms remain unknown.Here,we identified transcription factors involved in indoleacetic acid(IAA)and ethylene(ET)signaling that directly regulate the expression of INFLORESCENCE DEFICIENT IN ABSCISSION(IDA)and its receptor HAESA(HAE),which are key components initiating abscission.Specifically,litchi IDAlike 1(LcIDL1)interacts with the receptor HAESA-like2(LcHSL2).Through in vitro and in vivo experiments,we determined that the auxin response factor LcARF5 directly binds and activates both LcIDL1 and LcHSL2.Furthermore,we found that the ETHYLENE INSENSITIVE 3-like transcription factor LcEIL3 directly binds and activates LcIDL1.The expression of IDA and HSL2 homologs was enhanced in Lc ARF5and Lc EIL3 transgenic Arabidopsis plants,but reduced in ein3 eil1 mutants.Consistently,the expressions of LcIDL1 and LcHSL2 were significantly decreased in Lc ARF5-and LcEIL3-silenced fruitlet abscission zones(FAZ),which correlated with a lower rate of fruitlet abscission.Depletion of auxin led to an increase in 1-aminocyclopropane-1-carboxylic acid(the precursor of ethylene)levels in the litchi FAZ,followed by abscission activation.Throughout this process,LcRF5 and LcEIL3 were induced in the FAZ.Collectively,our findings suggest that the molecular interactions between litchi AUXIN RESPONSE FACTOR 5(LcARF5)-LcIDL1/LcHSL2 and LcEIL3–LcIDL1 signaling modules play a role in regulating fruitlet abscission in litchi and provide a long-sought mechanistic explanation for how the interplay between auxin and ethylene is translated into the molecular events that initiate abscission.

关 键 词：AUXIN ETHYLENE fruit abscission IDA–HAE/HSL2 LITCHI 

分 类 号：S667.1[农业科学—果树学]