水稻OsYDA基因调控气孔发育的功能分析

气孔是植物特化的表皮结构,在植物蒸腾过程和与外界气体交换过程中起到重要作用。拟南芥YDA（AtYDA）是MAPK级联信号途径中的一种激酶（MAPKKK4）,它在叶片气孔的发育过程中起着负调控的作用。AtYDA功能缺失导致叶片气孔显著增加,而表达组成型激活形式的AtYDA（ΔN-YDA）则会导致表皮产生无气孔表型。本研究克隆了水稻中与AtYDA同源的2个基因OsYDA1和OsYDA2。在拟南芥中过量表达这2个基因都导致了叶片气孔密度的减少和叶片失水速率的降低。而表达ΔN-OsYDA1和ΔN-OsYDA2的转基因植株则呈气孔系数下降的表型。这表明OsYDA与AtYDA在调控气孔发育的功能上具有保守性。

Characterization of Rice OsYDA Gene in Regulating Stomatal Development

Stomata,the specialized structure in plant epidermis,play an important role in transpiration and gas exchange between plants and the environment.Arabidopsis YDA（AtYDA）,a kinase（MAPKKK4） in MAPK cascade,negatively regulates stomatal development.The loss-of-function mutation of AtYDA leads to significant increase in the production of leaf stomata,whereas the expression of constitutively active form of AtYDA（ΔN-YDA） results in repressed stomatal formation in leaf epidermis.In this study,we cloned two orthologs of AtYDA in rice,namely OsYDA1 and OsYDA2.Overexpression of either of these genes in Arabidopsis resulted in a significant decrease in stomatal density and water-loss rate.Likewise,the transgenic Arabidopsis plants expressing ΔN-OsYDA1 and ΔN-OsYDA2 displayed a dramatically reduced stomatal index phenotype.Taken together,these results demonstrate a conserved role for OsYDA and AtYDA in regulating stomatal development.