Evaluation of resistance to foot rot and analysis of disease resistance related indexes of 60 sweet potato germplasm resources
Foot rot of sweet potato is the main disease of sweet potato in Zhejiang Province in recent years,which se-riously affects the yield and quality of sweet potato.The purpose of this study was to explore sweet potato varieties with high resistance and to explore the characteristics of resistance-related physiological indexes and resistance-relat-ed genes,so as to provide scientific basis for the improvement of sweet potato varieties.The resistance to foot rot of 60 sweet potato germplasm resources was determined by wound inoculation method.The representative resistant and susceptible sweet potato varieties were selected to infect the Phomopsis destruens and the differences in the activities of antioxidant enzymes,malondialdehyde(MDA)content and the expression levels of resistance-related genes were analyzed.The results showed that among the 60 sweet potato germplasm resources,3 varieties were highly resistant to the disease,including Xu D1-26,Xu D10-139,and J7-44.Meanwhile,10 resistant,18 susceptible and 29 highly susceptible varieties were identified,respectively.Moreover,the resistance level of sweet potato to foot rot was relat-ed to the antioxidant capacity,membrane lipid peroxidation level and jasmonic acid signaling pathway regulation of sweet potato.We found that the activities of superoxide dismutase(SOD),peroxidase(POD)and catalase(CAT)in highly resistant varieties were significantly increased compared to highly susceptible varieties.By 120 hours post inoculation(hpi),the activities of POD and SOD in highly resistant varieties were 1.81 times and 3.75 times higher than those in highly susceptible varieties,and the activity of CAT in highly resistant varieties was 2.93 times higher by 48 hpi.However,the MDA content of highly resistant varieties was significantly lower than that of highly suscepti-ble varieties.Quantitative RT-PCR analysis showed that expression levels of the resistance-related genes IbWRKY1,IbBBX24 and IbNAC1 were up-regulated by 2.72,3.15 and 1.91 times in highly resistant varieties compared with highly susceptible varieties at 168 hpi.
sweet potatogermplasm resourcePhomopsis destruensresistance evaluationresistance index
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