2021年黑龙江省疑似大豆猝死综合症的病原鉴定

Identification of Pathogens for Suspected Soybean Sudden Death Syndrome in Heilongjiang Province in 2021

大豆猝死综合症(Sudden Death Syndrome,简称SDS)是美洲大豆生产中严重发生的一种大豆根腐病,已知由茄腐镰孢菌复合种群分支2的4种镰孢菌所引起;该病在中国尚未有报道,但近年来部分大豆田块中发现疑似症状。为探明引起黑龙江省大豆疑似SDS茄腐镰孢菌的种类及致病性与药剂敏感性,于2021年从饶河、鹤岗、黑河和虎林等地采集58株疑似SDS大豆,分离根部和茎基部病原菌,进行形态学观察和基于EF1-α与RPB2的多靶标分子鉴定,以及致病性、杀菌剂敏感性与种衣剂防效测定。结果显示:分离到的31个茄腐镰孢菌菌株能够侵染大豆黄化苗下胚轴,导致大豆生长期根部腐烂,并引起叶片脉间褪绿、斑驳等类似于SDS的症状;这些菌株均属于茄腐镰孢菌复合种群分支3,分为两个类群,其菌落和分生孢子形态基本相似,但接种第一类群菌株后大豆植株的褐色病斑及上下扩展程度更明显;两个类群的8个代表菌株均对多菌灵、嘧菌酯、苯醚甲环唑、吡唑醚菌酯和咪鲜胺等杀菌剂表现敏感,6.25%精甲霜灵·咯菌腈悬浮种衣剂拌种可抑制病菌侵染。本研究为该类大豆病害的监测与防控提供了参考。

Sudden Death Syndrome(SDS)is a kind of serious soybean root rot disease in the main soybean production area in America,thus far known that it is caused by four Fusarium species of Fusarium solani species complex clade 2.The disease has not been reported in China,but suspected symptoms have been found in some soybean fields in recent years.In order to find out the species,pathogenicity,and fungicide sensitivity of F.solani causing suspected SDS of soybean in Heilongjiang province,we collected 58 soybean plants,which showed suspected SDS,from Raohe,Hegang,Heihe,and Hulin in 2021,then isolated pathogens from the root and stem base,and carried out morphology observation,EF1-αand RPB2 based multitarget molecular identification,and tests of pathogenicity assay,fungicide sensitivity,and control effect of seed coating agent.The results showed that the 31 isolated F.solani strains can infect the hypocotyl of soybean etiolated seedlings,and cause root rot and interveinal chlorosis and mottled of leaves similar to SDS during the growth period of soybean.The strains all belong to clade 3 of F.solani species complex and can be divided into two groups;although the strains of the two groups displayed similar morphology on colonies and conidia,the brown lesion and the degree of up and down expansion of soybean plants inoculated with the first group of strains were more obvious.All eight representative strains of the three groups were sensitive to the fungicides carbendazim,azoxystrobin,difenoconazole,pyraclostrobin,and prochloraz,and 6.25%metalaxyl-M+fludioxonil suspension seed coating agent could inhibit their infection to seed.The results will provide a reference for the monitoring and control of this kind of soybean disease.