【摘要】 独角金内酯是调控水稻分蘖的重要激素,在拟南芥中AtMAX1编码细胞色素P450蛋白,是独角金内酯合成途径的重要基因。通过同源序列比对,发现在水稻中有5个MAX1同源基因,包括OsMAX1a、OsMAX1b、OsMAX1c、OsMAX1d和OsMAX1e。分析5个OsMAX1基因的转录水平,发现OsMAX1a和OsMAX1e基因能够在水稻组织中稳定高效表达。对OsMAX1a和OsMAX1e的基因功能进行了验证,在拟南芥中过量表达OsMAX1a和OsMAX1e基因能够使max1突变体多分支表型恢复正常;在水稻中干涉OsMAX1a和OsMAX1e基因的表达能够增加水稻分蘖数。进一步的研究表明,外施GR24能够抑制OsMAX1a和OsMAX1e基因的表达,磷饥饿条件能够提高两个基因的表达水平从而促进独角金内酯的合成。另外,外施生长素和激动素能够显著影响OsMAX1a和OsMAX1e的表达。因此,OsMAX1a和OsMAX1e基因参与了独角金内酯的合成,并且在水稻生长发育中响应植物激素信号的诱导,是调控水稻分蘖的重要基因。更多还原

【Abstract】 Strigolactones(SLs)are a class of phytohormone which play essential roles in regulating rice tillering,and ATMAX1 in Arabidopsis encodind P450 is an important gene involved in the synthesis of SLs.Our study found five MAX1 homologous genes through BLAST,namely OsMAX1 a,OsMAX1b,OsMAX1 c,OsMAX1dand OsMAX1 e.Among them,OsMAX1 aand OsMAX1ehave stable and high expression in rice tissues.Our experiments verified that the overexpression of OsMAX1 aand OsMAX1ein Arabidopsis rescued the max1 branched mutant phenotype,and the interference of OsMAX1 a and OsMAX1 eexpression in rice increased rice tillering number.Furthermore,enogenous GR24 application inhibited the expression of OsMAX1 aand OsMAX1e,and P-starvation enhanced the expression of OsMAX1 aand OsMAX1e,thus promoted the biosynthesis of SLs.In addition,IAA and Kinetin(a cytokinin:KT)treatment apparently had remarkable effect on the expression of OsMAX1 aand OsMAX1e.The results demonstrated that the expression of OsMAX1 aand OsMAX1eresponded to the SLs level and they were involved in the synthesis of SLs and regulated rice tillering.更多还原