瓜尔豆细菌性疫病种子带菌检测及寄主范围测定

Host Range and Seed Transmission of Xanthomonas axonopodis pv.cyamopsidis in Guar

瓜尔豆细菌性疫病是新疆新发现的一种病害,本文对4份瓜尔豆种子根据症状分为无症状型(占总调查种子数36.55%)、中间型(占总调查种子数51.94%)和严重变色型(占总调查种子数11.51%)三类,不同类型种子的室内发芽率、带菌率和出苗率存在明显差异,严重变色型种子发芽率最低,为31.11%;中间型和无症状型种子的发芽率相对较高,分别为87.78%和63.33%;在室内培养基上进行种子带菌率检测,结果表明,严重变色型种子的带菌率最高,为51.11%,中间型和无症状型的带菌率为31.11%和24.44%。在水琼脂上严重变色型种子的出苗率为42.00%;无症状种子和中间型的出苗率分别为71.67%和90.00%。盆栽幼苗出苗和发病实验结果显示,无症状种子的出苗率为83.33%,而严重变色种子的出苗率仅为40.00%;不同类型种子的带菌率存在明显差异,无症状种子的带菌率为59.18%,而严重变色种子的带菌率为84.38%,远高出无症状种子的发病率;表明种子严重变色(或带菌率较高)都会严重影响种子的质量,继而造成种子发芽率和田间出苗率的降低。人工接种寄主范围测定结果显示,瓜尔豆细菌性疫病还可以感染、大豆(Glycine max)、豇豆(Vigna unguiculata)、绿豆(Vigna radiata)和芸豆(Phaseolus coccineus L.var.albonanus Baile)等豆科作物。

Bacterial blight of guar （Cyamopsis tetragonoloba L.） caused by Xanthomonas axonopodis pv.cyamopsidis （XAC） was a new disease in field-grown gumin Xinjiang.Four samples of dry guar seeds were collected from Xinjiang.They were classified into three categories according to the phenotypic characteristic,asymptomatic （36.55%）,moderately discoloured （51.94%） and shrivelled-discoloured （11.51%）,respectively.Germination rate and infection rate of different symptom seeds were significant distinctive as the YDC agar medium plate method shown.The germination rate and infection rate of seed were 31.11% and 51.11% in heavily discoloured sample,87.78% and 31.11% in moderately discoloured sample and 63.33% and 24.44% in asymptomatic sample, respectively;the emergence rates of seedling were 42.50%,90.00% and 71.67% incubation on 1% water agar test tube,respectively.The seed germination rates and the emergence rates of seedling were 83.33% and 59.18% in asymptomatic sample and 40.00% and 84.38% in shrivelled-discoloured sample in the pot experiment,respectively.The results demonstrated that severely infested seeds by X.axonopodis pv.cyamopsidis （XAC） resulted in less germination rate,and the quality of guar seed could be affected by XAC.The host range test of XAC showed that the pathogen could infect Cyamopsis tetragonoloba, Glycine max, Vigna unguiculata, Vigna radiata and Phaseolus coccineus L.var.albonanus Baile,moderately infect Vigna umbellata,couldn＇t infect Pisum sativum, Cicer arietinum,Phaseolus vulgaris and Arachis hypogaeain in artificial inoculated pods.