镰刀菌对南方根结线虫卵的寄生特性

Parasitism of isolates of Fusarium spp.to Meloidogyne incognita eggs

体外测定了分离于线虫的镰刀菌(Fusariumspp.)7个种的12个分离物对南方根结线虫(M eloidogyne incognita)卵的寄生性.结果表明:不同分离物对卵的寄生率有较大差异,有4个分离物对胚胎期卵的寄生率高于50%;所有分离物对含幼虫卵的寄生率低于40%;尖孢镰刀菌Fo-He3、茄病镰孢Fs-02100855对这2种发育类型的卵寄生率较高.测定了这12个镰刀菌分离物中几丁质酶活与蛋白酶活,结果表明,尖孢镰刀菌Fo-He3、茄病镰孢Fs-02100855表现出较高的几丁质酶活,这可能与卵寄生率高具相关性.扫描显微观测结果表明茄病镰孢Fs-02100855菌丝与胚胎期卵接触后,在卵壳表面蔓延侵入,最终卵壳完全被匐匍网状菌丝包被;含幼虫卵的卵壳表面蔓延侵入的菌丝很少.

Twelve isolates of 7 species of Fusarium, isolated from nematodes were assayed in vitro for their abilities to parasitize eggs of M. incognita. The results were as follows ： the isolates of Fusarium spp. varied considerably in ability to colonize eggs ; the percentages of eggs colonized by 4 isolates at embryonic stage were higher than 50% ; the percentages of eggs colonized by all isolates at the stage of bearing juveniles were less than 40% ; the isolates of F. oxysporium Fo-He3 and F. solani Fs-02100855 showed higher capacity for infection on eggs at embryonic stage or at the stage of bearing juveniles. Chitinase activities or protease activities of 12 isolates were studied on solid medium. The results of higher chitinase of F. oxysporium Fo-He3 or of F. solani Fs-02100855 sugges- ted a correlation between ability of parasitism and chitinase activity. The characters of colonization of F. solani Fs-02100855 on egg shells were observed under scan electron microscope. Upon hyphae contact with eggs at embryonic stage, growth profuse continued, the egg shell encircled entirely by hyphae eventually, but the quantity of hyphae encircled on egg shell of eggs at the stage of bearing juveniles was very few.