白粉病对小麦品种西农979籽粒淀粉合成关键酶基因表达的影响

为了揭示白粉病对花后小麦籽粒淀粉合成的影响机制,以小麦品种西农979为材料,利用实时荧光定量PCR技术研究白粉病不同发病程度对小麦籽粒淀粉合成相关酶基因表达的影响。结果表明,随着感病程度的增加,小麦籽粒的腺苷二磷酸葡萄糖焦磷酸化酶基因AGPase、淀粉分支酶基因SBE和可溶性淀粉合成酶基因SSS的表达均被抑制,其酶活性下降;束缚态淀粉合成酶I基因GBSSⅠ的表达量和酶活性均高于对照;去分支酶基因DBE的表达量与对照相比没有明显变化,但其酶活性在病害高峰期高于对照;支链淀粉含量和总淀粉含量显著降低,而直链淀粉含量增加。由此可知,白粉病通过改变籽粒淀粉合成相关酶基因的表达及活性而影响淀粉的积累。

Impact of Powdery Mildew on Gene Expression Related to Starch Synthesis of Wheat Cultivar Xinong 979

To determine the impact of powdery mildew on gene expression related to starch synthesis of wheat grain,the susceptible wheat variety Xinong 979 was used as experiment material.The expression levels of five starch synthase genes were investigated by quantitative real-time PCR,including ADP-glucose pyrophosphorylase gene(AGPase),granule bound starch synthase Ⅰ gene(GBSS f),soluble starch synthase gene(SSS),starch branching enzyme gene (SBE) and starch debranching enzyme gene(DBE).The change of starch synthase(AGPase,GBSS Ⅰ,SSS,SBE and DBE) activity was measured during grain development stages as well.The results indicated that,compared with control,the expression of AGPase,SBE and SSS was depressed in infected wheat during grain development.However,the gene expression level and enzyme activity of GBSSⅠwere higher in infected grains than in control.The expression of DBE had no significant difference in infected grains and control grains,but enzyme activity of DBE was higher in infected grains than in control.In addition,amylopectin content and total starch content were significant reduced in infected grains compared with control with the development of infection,but the content of amylose was increased in infected grains.These results suggested that powdery mildew could inhibit the accumulation of starch by impacting the expression levels and enzyme activities of starch synthases during grain filling stage.