杨树CYCD基因的功能鉴定及其对糖和植物激素的响应(英文)

D-Type Cyclin Family in Populus:Functional Characterization and Expression Profiling under Phytohormones and Sucrose Treatment

G1到S期的转换是植物细胞周期中一个关键的调控点,而D型细胞周期蛋白(CYCD)在这一转换过程中起着重要作用。CYCD通过感受外界信号的刺激,调控细胞周期进程,进而影响植物的生长发育。为研究木本植物中不同CYCD基因家族的功能,从黑杨中克隆出6个CYCD基因,并将其转化至酵母G1期细胞周期蛋白突变体进行功能鉴定。各家族CYCD基因均能对酵母突变体进行回补,但回补后促进酵母生长的能力存在差异。通过对黑杨组培苗进行糖和植物激素处理,观察到黑杨根部形态发生改变,同时用实时荧光定量PCR技术检测了该处理条件下CYCD基因表达量的变化。结果表明,各CYCD基因家族的代表成员对糖和植物激素的响应不同,反映了不同黑杨CYCD基因在树木生长发育过程中所起作用的差异性。

The G1/S transition is one of the key regulatory points during the plant cell cycle. D-type cyclins （CYCDs） play critical roles in controlling the progression through the G1 into the S phase. Since CYCDs are responsive to stimulatory signals, they are functional in integrating mitogenic signals into cell division. However, the expression patterns and functional characteristics of different CYCD families in woody species remain to be elucidated. Six putative CYCD genes designated as PdCYCD1-7 from a hybrid poplar clone （P. deltoides x P. nigra, NE19 ） by complementing a yeast mutant lacking G1 cyclins were identified. But their effects on promoting yeast cell division after ectopic expression are divergent. Sucrose and phytohormone treatments on in vitro-grown poplar seedlings led to the alteration of morphological traits in roots. The effects on the transcript levels of PclCYCDs were monitored. Differential expression characteristics of the CYCDs in response to the mitogen supply were observed. Though CYCDs were induced by sucrose, their extents of induction among CYCD subgroups varied. PdCYCD6 ; 4 and PdCYCD3 ; 1 may have wider roles in responding to external signals than others, for they were modulated with sucrose and most hormones treatments. The induction of PclCYCD2 ; 1 and PdCYCD1 ; 1 by hormones depended on the presence of sucrose. PdCYCD5 ; 1 was greatly stimulated by ethylene and the strengthening effect on induction was observed when sugar and hormones were added together. PdCYCD7;1 was not so sensitive to sucrose but was upregulated by gibberellin and ethylene. Together, these results suggest that the six populus CYCD genes identified here are functional in rescuing yeast cyclin mutant but may still have group-specific functions during the development of plants.