拟南芥JAG基因调控花器官中叶绿素a与b比例

JAG's regulation in controlling the chlorophyll a/chlorophyll b ratio in Arabidopsis floral organ

拟南芥C2H2锌指家族转录因子JAGGED(JAG)基因是植物发育过程中调控细胞分裂和分化的一个关键基因.为更详细了解JAG基因在植物发育调控中的功能,解析其下游的调控网络,通过对JAG基因诱导过表达植物的花器官进行分析,发现除在花器官形态上表现出差异外,JAG基因还可促进叶绿素a(chlorophyll a,Chla)转变为叶绿素b(chlorophyll b,Chlb).进一步研究发现,调控从Chla向Chlb转化的关键基因CAO的转录水平受JAG转录因子的间接作用会显著上调,从而使花器官中Chla和Chlb比例改变.对比分析JAG下游基因库转录组数据和Ch IPseq结果,找到了23个受JAG直接作用的叶绿体发育相关基因.研究结果表明,JAG基因对植物花器官中叶绿素的生成有重要作用,可通过间接调控CAO基因的表达,控制Chla和Chlb的比例.该工作可为研究JAG基因调控植物器官发育及功能的基因网络提供新启示.

JAGGED（JAG）,a C2H2 zinc finger transcription factor,is a key regulator of cell division and differentiation in Arabidopsis. Studies on dissecting its complex downstream regulatory network have attracted plant biologists for many years. To further dissect the role of JAG and analyze the downstream regulation network,we investigate the floral phenotypes of transgenic plants overexpressing an inducible form of JAG and observe the strong morphological defects in flower development when JAG is induced. Furthermore,we also detect a significant change of the chlorophyll a/b ratio in the JAG-overexpressing floral tissues. Subsequent gene expression assay shows that this phenotype is likely attributable to the increased level of CAO,a key factor involved in chlorophyll a to btransition. In the JAG overexpression plant,this regulation of CAO by JAG appears to be indirect. In addition,we also analyze the published micro-array and Ch IPseq data that have been used for identifying the target genes of JAG,and reveal that 23 JAG direct targets are associated with chloroplast development. These results suggest the potential important role of JAG in controlling chlorophyll biogenesis and will hopefully provide new insights in understanding the regulatory mechanisms of JAG in plant organ development and function.