高温胁迫对禾谷镰孢生长和致病力的影响

The effect of heat stress on the growth and aggressiveness of Fusarium graminearum isolates

为探究高温胁迫对禾谷镰孢生长和致病力的影响,本研究测定了禾谷镰孢5株耐高温菌株和4株温度敏感型菌株在25℃和30℃下的菌丝生长速率、产孢量、孢子萌发率以及不同胁迫压力下的生长速率、致病力和DON毒素含量等。结果表明,不论耐高温菌株还是温度敏感型菌株,30℃高温对其菌丝生长均有抑制作用,但对产孢量和孢子萌发有促进作用;30℃高温能减轻NaCl和CaCl2胁迫对禾谷镰孢生长的抑制,但是不影响KCl、刚果红,SDS和H2O2对病原菌的抑制作用;在30℃下,大部分耐高温菌株的致病力不变或降低,而大部分温度敏感型菌株的致病力反而增加,30℃对大部分菌株的DON毒素产量有一定促进作用。研究结果可为研究气候变化下小麦赤霉病的流行和预测提供理论基础。

In order to explore the effect of heat stress on the growth and aggressiveness of Fusarium graminearum,we measured the mycelia growth,sporulation,spore germination,osmotic stress,aggressiveness and DON production of five heat-tolerant isolates and four heat-sensitive isolates at 25℃and 30℃.The results showed that the mycelial growth was inhibited but the sporulation and spore germination were promoted at 30℃for both heat-tolerant and-sensitive isolates.The high temperature(30℃)treatment reduced the inhibition caused by NaCl and CaCl 2 osmotic stress to the growth of F.graminearum isolates,but showed no effect on the inhibition caused by KCl,Congo Red,SDS and H 2O 2 stress.Furthermore,the aggressiveness remained unchanged or decreased at 30℃in most heat-tolerant isolates,while increased in most heat-sensitive isolates,and high temperature(30℃)had a certain promoting effect on the production of DON toxins in most isolates.This study provides a theoretical basis for the prevalence and forecasting of Fusarium head blight under climate change.