两株木霉共培养发酵提高对小麦苗期茎基腐病的防治效果

Co-culturation of two Trichoderma strains enhanced control efficiency against wheat crown rot at seedling stage

通过平板对峙培养法、孢子萌发法和温室盆栽法筛选高效防治小麦苗期茎基腐病的木霉共培养菌株。从17株供试菌株中,筛选出3株平板抑制率较高的木霉菌株:深绿木霉HB20111、哈茨木霉LTR-2和TW21990,并进行两两组合共培养发酵。孢子萌发试验表明,HB20111+TW21990共培养发酵滤液对假禾谷镰孢孢子萌发抑制率最高,达71.83%,较单菌株HB20111和TW21990分别提高了6.13%和19.53%(P<0.05)。温室条件下,HB20111+TW21990共培养发酵液500×稀释浸种效果最好,对小麦苗期茎基腐病防治效果和幼苗质量增长率分别达78.81%和130.80%,较单菌株HB20111和TW21990的分别提高了17.88%、30.46%和50.05%、61.22%(P<0.05);荧光定量检测结果表明,与单菌株相比,HB20111+TW21990共培养发酵显著降低假禾谷镰孢在小麦幼苗根围土、根际土、根系和茎基部中的拷贝数(P<0.05),且假禾谷镰孢拷贝数与病情指数呈正相关,与幼苗鲜质量呈负相关。本研究发现HB20111+TW21990共培养发酵具有增效作用,对小麦苗期茎基腐病的防治效果显著高于单菌株。

We evaluated the inhibitory efficiency of 17 Trichoderma strains against Fusarium pseudograminearum(Fp),the predominant causal agent of wheat crown rot through dual plate confrontation assay.Among them,T.atroviride HB20111,T.harzianum LTR-2 and TW21990 exhibited higher inhibition rates,which were selected for co-culturing.The fermentation filtrate of HB20111+TW21990 had 71.83%inhibition rate for Fp spore germination,which significantly increased by 6.13%and 19.53%respectively,compared with single strain HB20111 and TW21990.In greenhouse condition,the 500×dilution fermentation broth was the most effective treatment to control wheat seedling crown rot and increase the weight of seedling fresh at rate of 78.81%and 130.80%.Compared with the single strain HB20111 and TW21990,the efficiencies of the paired were significantly increased by 17.88%,30.46%and 50.05%,61.22%,respectively.As expected,real-time quantitative PCR(qPCR)analysis showed that co-culturing fermentation treatment could significantly reduce the Fp DNA copy numbers in the bulk soil,rhizosphere soil,root and basal stem,which were positively correlated with the disease index while negatively with the seedlings fresh weight.Therefore,the co-culturation of HB20111+TW21990 had a synergistic effect on control of wheat crown rot to a greater extent than the single strain.