玉米南方锈病鉴别寄主筛选及其在病菌致病型研究中的应用

Screening of the differential host spectrum of southern corn rust and its application in the study of pathogenic type

由多堆柄锈菌Puccinia polysora Underw.引起的玉米南方锈病是一种暴发性和气传性的大区流行性病害,流行年份可造成严重的产量损失。病害流行主要是由病原菌毒性优势小种所致,但我国目前尚缺乏玉米南方锈菌生理小种的研究,给该病害的预测预报及防治带来许多困难。本研究在温室对采自不同地区玉米南方锈菌的分离物在含已知抗性基因的自交系及骨干自交系上进行了苗期抗性鉴定,根据基于生物间遗传学方法计算的不同玉米自交系毒力频率,筛选出具有鉴别能力的‘CML470’、‘齐319’、‘F939’、‘W2D’、‘P138’、‘昌-470’、‘X178’和‘黄早四’8个自交系,构建了一套玉米南方锈菌鉴别寄主谱,并对我国玉米南方锈菌致病型进行了研究,共发现14种致病型,其中1号致病型(只能侵染黄早四)的频率最高,为0.58,其在2016年和2017年均被发现,且分布区域广,在海南,广西,广东,山东等7个省份均存在,是目前我国玉米南方锈菌的主要流行致病型,由此确定为我国玉米南方锈菌的一个新的生理小种,命名为南中1号生理小种(NZ1),这也是我国内地第一个正式命名的玉米南方锈菌生理小种。

Southern corn rust caused by Puccinia polysora Underw.,is a fulminant and airborne disease,which can cause serious losses during epidemic years.Many studies at home and abroad have shown that the physiological races of P.polysora were very abundant,and the epidemic of plant diseases was mainly caused by the dominant races of P.polysora,but there were few research reports on the physiological races of P.polysora in China,so it brings many difficulties to the prediction and prevention of this disease,and has become a bottleneck in corn production.Based on the current research on the resistance genes and resistant inbred lines of southern corn rust in China,this study selected inbred lines containing known resistance genes and backbone inbred lines in maize production as differrential to be identified.Isolates of southern corn rust collected from different regions were used to identify these inbred lines resistance at the seeding in greenhouses,and the virulence frequency(VF)of different inbred lines.Then the inbred lines with the ability to identify different pathotype were selected to construct a set of differrential,and the pathotypes of southern corn rust in China was studied.14 pathotypes were identified.Among them,pathotype 1,which can only infect Huangzaosi,with the highest frequency of 0.58,was the dominant pathotype of P.polysora in China,which could be found from 7 provinces such as Hainan,Guangxi,Guangdong,shandong,etc.in 2016 and 2017.This pathotype,which can be determined as a new physiological race of southern corn rust pathogen in China.This is the first physiological race of P.polysora identified in China,temporarily named as Nanzhong1(NZ1).