gdo基因RNAi对小麦全蚀病菌的影响

Effects of RNA Interference of gdo on Gaeumannomyces graminis, the Wheat Take-all Fungus

为了筛选可利用寄主诱导基因沉默(HIGS)技术防治小麦全蚀病的靶基因,利用RNA干涉(RNAi)技术探讨了编码龙胆酸1,2-双加氧酶(Gentisate 1,2-dioxygenase,GDO)的gdo基因沉默对小麦全蚀病菌KX-7菌丝生长速率和致病能力的影响。结果表明,gdo基因沉默明显抑制全蚀病菌的生长速率,参试30个转化子在PDA平板上的相对生长速率只有野生型对照的20.00%~87.00%。gdo基因沉默转化子使小麦致病力下降,但转化子之间有明显差异。侵染小麦28 d后,L-4转化子的小麦病情指数为39.29,明显低于野生型对照病情指数(75.93)。离体培养结果表明,菌丝相对生长速率和致病能力之间无明显相关关系。4个转化子菌丝在PDA平板上的相对生长速率为S-6(59.00%)=L-2(59.00%)>L-4(42.00%)>M-5(30.00%),受其侵染小麦的病情指数为S-6(84.00)>M-5(77.08)>L-2(62.07)>L-4(39.29)。初步证实gdo基因可以作为HIGS技术防治小麦全蚀病的候选靶基因。

In order to select the target genes used in host-inducing gene silencing(HIGS)to protect wheat from damages caused by Ggt(Gaeumannomyces graminis var.tritici),the effects on growth and pathogenicity of Ggt fungus KX-7 caused by RNA interference(RNAi)of gdo gene which encodes gentisate 1,2-dioxygenase(GDO)were investigated.The results showed that,gdo gene silencing caused by RNAi obviously inhibited hyphae growth of the fungus.The relative growth rates of hyphae of thirty Ggt transformants in vitro cultured on solid PDA medium were only 20.00%—87.00%of wild type control.gdo RNAi in Ggt cells lessened the pathogenicity of transformants to wheat plants at different extents.Based on wheat resistance evaluation twenty-eight days post inoculation with gdo RNAi transformants,disease index of transformant L-4 infected wheat plants was 39.29,obviously lower than wild type control(75.93).The results of in vitro culture showed that there was no obvious correlation between hyphae relative growth rate and Ggt pathogenicity.Hyphae relative growth rate of four tested transformants was orderly from high to low by S-6(59.00%)=L-2(59.00%)>L-4(42.00%)>M-5(30.00%),whereas the disease index of infected plants was in descending order of S-6(84.00)>M-5(77.08)>L-2(62.07)>L-4(39.29).This study confirmed that gdo gene could be used as a candidate target gene in HIGS for the protection of wheat from Ggt.