水稻丙酮酸脱羧酶基因OsPDC3功能的初步研究

Primary Function Analysis of a Pyruvate Decarboxylase Gene,OsPDC3,in Rice

植物花粉中存在着活跃的有氧发酵过程。丙酮酸脱羧酶(PDC)作为发酵途径中的关键酶,参与花粉中的能量和物质代谢,在花粉萌发过程中起重要作用。通过反向遗传学的方法对水稻丙酮酸脱羧酶基因OsPDC3的功能进行了初步分析。OsPDC3是一个单外显子基因,编码蛋白与另外4个水稻PDC蛋白间的序列一致性达到77%～82%。表达模式分析显示OsPDC3在花粉中特异表达,GUS组织染色进一步证实其启动子具有花粉特异表达活性。超量表达OsPDC3会使转基因植株叶片中的PDC酶活性上升,表明OsPDC3在体内具有活性功能,能够参与花粉内的生理活动。反义抑制下调了OsPDC3在花粉中的表达水平,但对花粉的离体萌发率没有产生影响,推测这是由于PDC基因间的冗余造成的。

There are high aerobic fermentation rates in plant pollen.As a key enzyme of ethanolic fermentation pathway,pyruvate decarboxylase（PDC） is involved in energy production and biosynthesis in pollen,playing an important role in the pollen germination process.OsPDC3 gene function was investigated by the reverse genetics methods.The gene is a single exon gene encoding a protein that shares 77%-82% sequence identity with other rice PDC proteins.Expression pattern analysis showed that the OsPDC3 specifically expressed in pollen,and the pollen specific expression activity of the promoter of OsPDC3 was confirmed by GUS staining.Overexpression of OsPDC3 in transgenic plants improved the activity of PDC in leaves,indicating functional enzyme activity of OsPDC in vivo.Antisense suppression down-regulated the expression of OsPDC3 in pollen,but the pollen germination rate in vitro remained unchangable,which might attribute to the redundancy among the PDC genes.