AtVPS15通过影响PI3P的合成对拟南芥花粉发育和花粉管的生长有重要作用

【作者】 徐娜； 高新起； 赵新英； 朱东姿； 周良子； 张宪省；

【机构】 山东农业大生命科学学院；

【摘要】 拟南芥磷酸肌醇三激酶(AtVPS34)通过合成磷酸三肌醇(PI3P)对拟南芥花粉发育和花粉管的生长有重要作用。在酵母中,Vps15p是Vps34p的膜定位和活性所必需的。作为Vps15的同源基因,拟南芥VPS15(AtVPS15)主要在花粉和花粉管中表达。为了研究它在拟南芥花粉发育和花粉管生长过程中的作用,我们分离了一个AtVPS15基因的T-DNA插入突变体,但是,在杂合体的后代中,我们无法分离到其纯合突变体。遗传学的分析结果表明,后代分离比的异常是由于基因通过花粉传递的异常造成的。杂合体大部分的花粉粒是可以存活下去的,有正常的表面结构和细胞核,但是一些成熟的花粉粒与野生型相比含有异常的大液泡。杂合体花粉的萌发率与野生型相比,大约是野生型的一半。当我们外源施加了PI3P,杂合体花粉的体外萌发得到显著提高。由此我们推测,AtVPS15通过影响PI3P的合成对拟南芥花粉发育和花粉管的生长有重要作用。更多还原

【Abstract】 Arabidopsis thaliana phosphatidylinositol 3-kinase(AtVPS34) functions in the development and gennination of pollen by catalyzing the biosynthesis of phosphatidylinositol 3-phosphate (PDP).In yeast,Vps15p is required for the membrane targeting and activity of Vps34.The expression of Arabidopsis thaliana VPS15(AtVPS15),an ortholog of yeast Vps15,is mainly detected in pollen grains and pollen tubes.To determine its role in pollen development and pollen tube growth,we attempted to isolate the T-DNA insertion mutants of AtVPS15;however,homozygous lines of atvps15 were not obtained from the progeny of atvps15/+ heterozygotes.Genetic analysis revealed that the abnormal segregation is due to the failure of transmission of the atvps15 allele through pollen.Most pollen grains from the atvps15/+ Genotype are viable,with normal exine structure and nuclei.The germination ratio of pollen from the atvps15/+ genotype is about half when compared to that from the wild AtVPSlS genotype.When supplied with PDP,in vitro pollen germination of the atvps15/+ genotype is greatly improved.Presumably, AtVPS15 functions in pollen development and germination by regulating PDP biosynthesis in Arabidopsis.更多还原