Effect of Azoxystrobin on Oxygen Consumption and cyt b Gene Expression of Colletotrichum capsici from Chilli Fruits

Azoxystrobin acts as an inhibitor of electron transport by binding to the Qo center of cytochrome b (cyt b).Resistance to azoxystrobin was usually caused by the point mutation of cyt b gene or by the induction of alternative respiration.Oxygen consumption test for mycelia of Colletotrichura capsici showed that azoxystrobin inhibited mycelial respiration within 12 h; however,as time went on,the respiration of the mycelia recovered when the mycelia were treated with azoxystrobin and salicylhydroxamic acid (SHAM,a known inhibitor of alternative respiration),and the oxygen consumption of the mycelia could not be inhibited.Meanwhile,cytochrome b (cyt b) gene expression increased with the recovery of myeelial respiration.The increased cyt b gene expression might play a role in the development of resistance to azoxystrobin in C.capsici.