华中农业大学匡汉晖研究团队再探生菜结球的奥秘

　　The mechanisms underlying leafy heads in vegetables are poorly understood. Here, we clo ned a quantitative trait locus （QTL� co ntrolling leafy heads in lettuce （Lactuca sativa）� The QTL encodes a trans cription factor, SAWTOOTH 1 （LsSAW1）， which has a BEL1-like homeodomain and is a homolog of Arabidopsis thaliana. A 1-bp deletion in Lssaw1 co ntributes to the development of leafy heads. Laser-capture microdissection and RNA-sequencing showed that LsSAW1 regulates leaf dorsiventrality and loss-of-function of Lssaw1 downregulates the ex pression of many adaxial genes but upregulates abaxial genes. LsSAW1 binds to the promoter region of the adaxial gene ASYMMETRIC LEAVES 1 （LsAS1� to upregulate its ex pression. Overex pression of LsAS1 compromised the effects of Lssaw1 on heading. LsSAW1 also binds to the promoter region of the abaxial gene YABBY 1 （LsYAB1）， but downregulates its ex pression. Overex pression of LsYAB1 led to bending leaves in LsSAW1 genotypes. LsSAW1 directly interacts with KNOTTED 1 （LsKN1）， which is necessary for leafy heads in lettuce. RNA-seq data showed that LsSAW1 and LsKN1 exert antago nistic effects on the ex pression of thousands of genes. LsSAW1 compromises the ability of LsKN1 to repress LsAS1. Our results suggest that downregulation or loss-of-function of adaxial genes and upregulation of abaxial genes allow for the development of leafy heads.

　　论文链接：https://academic.oup.com/plcell/advance-article/doi/10.1093/plcell/koac234/6653310