The transcription factor HBF1 directly activates expression of multiple flowering time repressors to delay rice flowering  

作　　者：Cong Li Liya Zhang Xin Wang Chunsheng Yu Tao Zhao Bin Liu Hongyu Li Jun Liu Chunyu Zhang 

机构地区：[1]Institute of Crop Science,Chinese Academy of Agricultural Sciences,Beijing 100081,China [2]Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement and Guangdong Provincial Key Laboratory of Applied Botany,South China Botanical Garden,Chinese Academy of Sciences,Guangzhou 510650,China [3]Institute of Nanfan and Seed Industry,Guangdong Academy of Sciences,Guangzhou 510316,China

出　　处：《aBIOTECH》2023年第3期213-223,共11页生物技术通报（英文版）

基　　金：supported by grants from the National Natural Science Foundation of China(No.31771758);the National Transgenic Major Project of China(No.2018ZX0800925B)。

摘　　要：Flowering time(or heading date)is an important agronomic trait that determines the environmental adaptability and yield of many crops,including rice(Oryza sativa L.).Hd3a BINDING REPRESSOR FACTOR 1(HBF1),a basic leucine zipper transcription factor,delays flowering by decreasing the expression of Early heading date 1(Ehd1),Heading date 3a(Hd3a),and RICE FLOWERING LOCUS T 1(RFT1),but the underlying molecular mechanisms have not been fully elucidated.Here,we employed the hybrid transcriptional factor(HTF)strategy to enhance the transcriptional activity of HBF1 by fusing it to four copies of the activation domain from Herpes simplex virus VP16.We discovered that transgenic rice lines overexpressing HBF1-VP64(HBF1V)show significant delays in time to flower,compared to lines overexpressing HBF1-MYC or wild-type plants,via the Ehd1–Hd3a/RFT1 pathway,under both long-day and short-day conditions.Transcriptome deep sequencing analysis indicated that 19 WRKY family genes are upregulated in the HBF1V overexpression line.We demonstrate that the previously unknown gene,OsWRKY64,is a direct downstream target of HBF1 and represses flowering in rice,whereas three known flowering repressor genes,Days to heading 7(DTH7),CONSTANS 3(OsCO3),and OsWRKY104,are also direct target genes of HBF1 in flowering regulation.Taking these results together,we propose detailed molecular mechanisms by which HBF1 regulates the time to flower in rice.

关 键 词：HBF1 bZIP transcription factor OsWRKY64 Flowering time RICE 

分 类 号：S511[农业科学—作物学]