Cotton BLH1 and KNOX6 antagonistically modulate fiber elongation via regulation of linolenic acid biosynthesis  

作　　者：Tingting Jia Huiqin Wang Shiyan Cui Zihan Li Yongcui Shen Hongbin Li Guanghui Xiao 

机构地区：[1]College of Life Sciences,Shihezi University,Shihezi 832003,China [2]College of Life Sciences,Shaanxi Normal University,Xi’an 710062,China [3]Zhengzhou Research Base,State Key Laboratory of Cotton Biology,School of Agricultural Sciences,Zhengzhou University,Zhengzhou 450001,China [4]Geosystems Research Institute,Mississippi State University,Starkville,MS 39762,USA [5]These authors contributed equally to this work

出　　处：《Plant Communications》2024年第7期138-156,共19页植物通讯（英文）

基　　金：supported by the National Natural Science Foundation of China(32070549,32270578,and 32200444);the National Key Research and Development Program of China(SQ2022YFF1000028);the China Postdoctoral Science Foundation(2022M712005);the Natural Science Basic Research Plan in the Shaanxi Province of China(2022JQ-197);the Fundamental Research Funds for the Central Universities(GK202304016,GK202304018,GK202304015);the Xinjiang Production and Construction Corps Key Fields Science and Technology Research Plan(KC00310501).

摘　　要：BEL1-LIKE HOMEODOMAIN(BLH)proteins are known to function in various plant developmental processes.However,the role of BLHs in regulating plant cell elongation is still unknown.Here,we identify a BLH gene,GhBLH1,that positively regulates fiber cell elongation.Combined transcriptomic and biochemical analyses reveal that GhBLH1 enhances linolenic acid accumulation to promote cotton fiber cell elongation by activating the transcription of GhFAD7A-1 via binding of the POX domain of GhBLH1 to the TGGA cis-element in the GhFAD7A-1 promoter.Knockout of GhFAD7A-1 in cotton significantly reduces fiber length,whereas overexpression of GhFAD7A-1 results in longer fibers.The K2 domain of GhKNOX6 directly interacts with the POX domain of GhBLH1 to form a functional heterodimer,which interferes with the transcriptional activation of GhFAD7A-1 via the POX domain of GhBLH1.Overexpression of GhKNOX6 leads to a significant reduction in cotton fiber length,whereas knockout of GhKNOX6 results in longer cotton fibers.An examination of the hybrid progeny of GhBLH1 and GhKNOX6 transgenic cotton lines provides evidence that GhKNOX6 negatively regulates GhBLH1-mediated cotton fiber elongation.Our results show that the interplay between GhBLH1 and GhKNOX6 modulates regulation of linolenic acid synthesis and thus contributes to plant cell elongation.

关 键 词：cotton fiber BLH1 KNOX6 linolenic acid biosynthesis fiber cell elongation 

分 类 号：Q94[生物学—植物学]