INO80参与拟南芥气孔数量调控的分子机制

Molecular Mechanism of Chromatin Remodeling Factor INO80 in Regulating the Number of Stomata in Arabidopsis thaliana

气孔是植物表皮特有的结构,参与到植物的呼吸、蒸腾作用等多种生理活动.植物通过气孔与大气进行气体交换.INO80是一类保守的染色质重塑因子,可以与组蛋白变异体H2A.Z结合.与野生型相比,拟南芥ino80缺失突变体对于渗透压的敏感度及其失水率都有明显提高.与此相应的是,ino80缺失突变体植物表现出气孔明显增多的表型.bHLH转录因子家族中的SPCH和MUTE对于气孔的发育起到正调控的作用.RT-PCR检测显示,在ino80突变体的背景下,气孔正调控基因SPCH和MUTE的表达量都显著上调.ChIP-PCR实验显示,相对于野生型,H2A.Z在SPCH和MUTE上染色质的分布在ino80缺失突变体内下调.我们的工作表明,在拟南芥中,INO80可能通过调控气孔正调控基因染色质区域组蛋白变体H2A.Z的分布影响靶基因的转录水平,进而改变气孔数量以及植物的相应生理指标.

Stomata,the specified forms of the plant epidermis,are involved in plant respiration,transpiration and other physiological activities.INO80 is one highly conserved chromatin remodeling factor,which can interact with histone variant H2 A.Z.The osmotic sensitivity and transpiration rate were significantly enhanced in Arabidopsis ino80-deficient mutant compared with in wild type plants.In accordance,the leaves of ino80 mutant showed higher stomata amount compared with those of wild type.bHLH transcription factors SPCH and MUTE play apositive role in the regulation of stomatal development.RT-PCR analysis showed that the transcriptional levels of SPCH and MUTE were significantly up-regulated in ino80 mutant.ChIP-PCR experiments indicated that the distribution of histone variant H2 A.Z on the SPCH and MUTEchromatin regions was down regulated in ino80 mutant.Our work suggests that in Arabidopsis thaliana,chromatin remodeling factor INO80 modulates the transcriptional levels of key development genes of stomata probably through altering the distribution of H2 A.Z on target chromatin regions,as well as the stomata amount and plant physiological indexes.