Modulation of flowering by an alternatively spliced AGL18-1 transcript in Brassica juncea  

作　　者：Qinlin Deng Huanhuan Lu Dakun Liu Yifang Huang Junjie Feng Dayong Wei Zhimin Wang Qinglin Tang 

机构地区：[1]College of Horticulture and Landscape Architecture,Southwest University,Chongqing 400715,China [2]Chongqing Key Laboratory of Olericulture,Chongqing 400715,China

出　　处：《The Crop Journal》2025年第2期456-467,共12页作物学报(英文版)

基　　金：supported by grants from the National Natural Science Foundation of China(32172547).

摘　　要：Photoperiod and temperature are crucial factors that trigger flowering in Brassica juncea(B.juncea).However,the underlying regulatory mechanisms remain poorly understood.The MADS-box transcription factor AGL18 acts as a pivotal repressor of floral transition and functions redundantly with AGL15.In this study,we isolated BjuAGL18-1 from B.juncea and identified two unique transcripts,resulting in two distinct proteins:a full-length protein,BjuAGL18-1L,and a truncated protein,BjuAGL18-1S.Further investigation showed that the two isoforms had similar subcellular localizations but different expression patterns in various plant tissues.Notably,BjuAGL18-1L and BjuAGL18-1S were abundantly induced under short-and long-day photoperiods,respectively.BjuAGL18-1L overexpression in B.juncea and Arabidopsis thaliana(A.thaliana)led to late flowering,whereas BjuAGL18-1S overexpression resulted in early flowering.Yeast two-hybrid,bimolecular fluorescent complementation,and luciferase complementation assays showed that BjuAGL18-1L,but not BjuAGL18-1S(which lacked the EAR motif),interacted with the co-repressor BjuAFR2 and the histone deacetylase BjuHDA9 to form a multiprotein complex.Further analysis indicated that BjuAGL18-1L could also form a complex with BjuAGL15 and bind to the BjuFUL promoter,thus inhibiting its expression.However,BjuAGL18-1S interacted with BjuAGL18-1L to form heterodimers,which attenuated their activities,likely by disrupting their binding to target genes,resulting in accelerated flowering progression.These results suggest that BjuAGL18-1 is involved in photoperiod-induced flowering via different regulatory mechanisms in B.juncea.

关 键 词：Brassica juncea BjuAGL18-1 ISOFORM PHOTOPERIOD FLOWERING 

分 类 号：S565.9[农业科学—作物学]