甘肃和青海小麦条锈菌UV-B辐射敏感性测定

Investigation of UV-B sensitivity of Puccinia striiformis f.sp.tritici isolates from Gansu and Qinghai provinces,China

位于西北地区的甘肃和青海是我国小麦条锈病病原菌(Puccinia striiformis f.sp.tritici,Pst)重要的越夏区和菌源基地,也是Pst毒性变异频率较高地区,该区域海拔高,紫外线辐射强度大。为了解紫外线对Pst存活力和毒性变异的影响,本研究测定了分离自甘肃和青海部分地区21个Pst菌株夏孢子的相对萌发率和UV-B辐射LT50值(UV-B致死中时间,即在一定UV-B辐射强度下夏孢子相对萌发率为50%时所需辐射时间),探索了相应菌株对UV-B辐射的敏感性。结果表明,在3个UV-B辐射强度(150、200和250μw·cm^(-2))下,分离自甘肃和青海的全部Pst供试菌株的夏孢子相对萌发率均与UV-B辐射时间呈极显著负相关(P<0.0001)。3个UV-B辐射强度下的夏孢子相对萌发率和LT50值的比较结果表明,Pst菌株对UV-B辐射的敏感性存在差异,来自于青海的Pst菌株之间对UV-B辐射的敏感性差异高于来自于甘肃的Pst菌株。研究结果为探索紫外线对Pst存活力和毒性变异的影响提供了一定理论基础,为小麦条锈病的监测和防控提供了一定依据。

Gansu and Qinghai provinces,located in high altitude of the northwest of China with high-intensity ultraviolet(UV)radiation,are important oversummering and high-frequency virulence-variation areas for Puccinia striiformis f.sp.tritici(Pst)in China.To explore the effects of UV radiation on the survival and virulence variation of Pst,the UV-B sensitivity of 21 Pst isolates collected from some regions of Gansu and Qinghai provinces was investigated based on relative germination rates of the urediospores and the LT50(lethal time 50%,i.e.,radiation time required to obtain a lethal rate of 50%for the Pst urediospores under certain UV-B radiation intensity)values for all the Pst isolates.The results showed that the relative germination rates of urediospores of Pst isolates from Gansu and Qinghai were extremely negatively correlated with the time length of UV-B radiation under each of the three UV-B radiation intensities(150,200,and 250μw·cm^(-2))(P<0.0001).The comparison results of relative germination rates and LT50 values among all the isolates under the three UV-B intensities demonstrated that there were differences in sensitivity to UV-B radiation among all the Pst isolates and that the difference in sensitivity to UV-B radiation among the Pst isolates from Qinghai Province was higher than that among the Pst isolates from Gansu Province.In this study,a theoretical basis was provided for further studying virulence variation of Pst,and for monitoring,resistance breeding,and management of wheat stripe rust caused by Pst.