不同海拔对天水市小麦条锈菌夏孢子萌发的影响

Effects of different altitudes on the germination of urediospores of stripe rust pathogen Puccinia striiformis f.sp.tritici in Tianshui,Gansu

为明确不同海拔对天水市小麦条锈菌Puccinia striiformis f.sp.tritici夏孢子萌发的影响,于显微镜下观察天水市低、中、高海拔地区小麦条锈菌夏孢子在不同温度下的萌发及融合情况,并对与夏孢子萌发相关的温敏基因的表达水平进行测定。结果显示,低海拔和中海拔地区的小麦条锈菌夏孢子的最适萌发温度为9℃,萌发率分别为64.72%和54.21%,高海拔地区的小麦条锈菌夏孢子的适宜萌发温度在12~16℃之间,平均萌发率为59.09%;高海拔和低海拔地区小麦条锈菌夏孢子都存在芽管融合和孢子融合现象,其中高海拔地区小麦条锈菌夏孢子的异核率为6.13%,超过了其无性阶段变异的阈值1%。与夏孢子萌发相关的10个温敏基因在不同海拔地区小麦条锈菌夏孢子中的表达趋势不同,其中,与能量代谢相关的葡萄糖转运蛋白基因和低亲和力磷酸转运蛋白基因在高海拔地区小麦条锈菌夏孢子中的表达量高于低海拔地区小麦条锈菌夏孢子,与毒性变异相关的易化因子超家族(major facilitator superfamily,MFS)转运蛋白基因在高海拔和低海拔地区小麦条锈菌夏孢子中的表达模式均呈上升趋势。表明由于海拔引起的环境温度变化对小麦条锈菌夏孢子的萌发机制产生了一定影响。

In order to investigate the effects of different altitudes on the germination of stripe rust pathogen Puccinia striiformis f.sp.tritici(Pst)uredospores,the germination and fusion of Pst urediospores from different altitude areas were observed microscopically,and the expression levels of temperaturesensitive genes related to urediospore germination were determined.The results showed that the optimum germination temperature for Pst urediospores from low,middle and high altitudes were 9,9 and 12-16℃respectively,and the averaged germination rate of Pst urediospores at optimum germination temperature was 64.72%,54.21%and 59.09%,respectively.Germ tube fusion and spore fusion were observed in Pst urediospores from high and low altitude areas.The polynuclear rate of Pst urediospores from high altitude areas was 6.13%,which higher than the threshold of variation in asexual phase(1%).The ten genes related to temperature sensitivity of urediospore germination had different expression patterns among Pst urediospores from different altitude areas.The expression levels of glucose and low-affinity phosphate transporter involved in energy metabolism were higher in Pst urediospores from the high altitude area than those in urediospores from the low altitude area.The expression level of major facilitator superfamily(MFS)transcription factor related to the toxic variant was upregulated during urediospores germination in all strains.Taken together,the altitude-related temperature differences had an important impacts on the germination mechanism of urediospores.