禾谷镰孢的产毒与致病性

Correlation of trichothecene producing potential to pathogenicity of Fusarium graminearum on wheat

小麦穗期接种禾谷镰孢FusariumgraminearumSchw . [有性态 :Gibberellazeae (Schw .)Petch]的 2个野生型菌株和12个产毒潜能不同的转化体菌株 ,发病盛期 (接种后 2 0d)调查病小穗率 ,并测定组织中脱氧雪腐镰刀菌烯醇 (DON)、15 乙酰脱氧雪腐镰刀菌烯醇 (15 ADON)和 3 乙酰脱氧雪腐镰刀菌烯醇 (3 ADON)等单端孢霉烯族毒素 (以下简称“单族毒素”)的含量。结果显示 ,菌株间致病力存在显著差异。强致病力的GZ36 39、C11 1和B4 1等菌株在病穗 (显症 )组织和穗颈组织中DON产量高 ,分别达 2 9～ 38μg·g-1和 2 6～ 6 0 μg·g-1(以干重计 ,以下同 ) ,15 ADON在穗颈组织中的积累量为 15～ 31μg·g-1,显著高于病穗组织中的积累量 (5～ 7μg·g-1) ;另一强致病力菌株JF 12除在病穗和穗颈组织中产生大量DON (分别为 4 4和 5 5 μg·g-1)外 ,还产生大量的 3 ADON (分别为 17和 4 6 μg·g-1) ;不产毒的GZT 4 0 (产毒基因Tri5失活 ,Tri5 -)菌株接种后 ,仅在接种小花颖片上产生鸟眼状坏死斑点 ,病斑不扩展至其他小花和小穗 ,穗组织中也没有任何单族毒素积累 ;所有处理接种穗的健康 (无症 )组织中均没有明显的单族毒素积累 (<0 5 μg·g-1)。相关性分析表明 ,菌株的致病力与穗颈组织中DON和 15

The correlation between pathogenicity to cause wheat head scab and trichothecene producing potential in Fusarium graminearum Schw.(teleomorph:Gibberella zeae (Schw.)Petch)was studied.Conidial suspensions of fourteen strains with different trichothecene producing potentials were inoculated at heading stage on Su 8060,a moderately resistant wheat cultivar.Disease severity (percentage of diseased spikelets)was examined and amount of trichothecenes(deoxynivalenol(DON),15 acetyldeoxynivalenol(15?ADON)and 3 acetyldeoxynivalenol(3?ADON))in both symptomatic and asymptomatic spike tissues and in peduncles assayed 20 days after inoculation.The results showed that there was significant difference in pathogenicity among strains.Highly virulent strains(GZ3639(a wild type strain from USA),C11?1 and B4?1)produced high amount of DON in both symptomatic spike tissues and peduncles(29?38 μg·g -1 and 26?60 μg·g -1 on average,respectively).15?ADON accumulated more in peduncles(15?31 μg·g -1 )than in symptomatic spike tissues(5?7 μg·g -1 ) inoculated with these three strains.JF 12(another highly virulent wild type strain from China)produced high amount of DON(44 and 55 μg·g -1 ,respectively)and 3?ADON(17 and 46 μg·g -1 ,respectively)in symptomatic spike tissues and peduncles.Trichothecene nonproducing strain GZT40 caused bird′s eye shaped necrosis lesions that were limited to and could not spread from the inoculated florets,and resulted in no accumulation of trichothecenes.Correlation analysis indicated that a significant and positive correlation of pathogenicity of the pathogen existed to its DON or 15?ADON production in peduncles(r=0 93?0 95)but to any trichothecene production in symptomatic spike tissues.