【摘要】 <正>魔芋为天南星科(Araceae)魔芋属(Amorphophallus Blume)植物,是富含葡甘露聚糖的经济作物。随着人们对魔芋葡甘露聚糖的进一步研究和深度开发利用,魔芋的生产越来越受到重视,种植方式也由传统的半野生零星种植转向规模化大面积种植。云南是魔芋的起源中心之一[1],其气候环境非常适宜魔芋的生长和种植,但由于规模化种植程度的扩大以及芋农较为粗放的栽培管理方式,魔芋病害日趋严重,新病害亦不断出现。20世纪90年代初,我国魔芋有3种主要病害,现已增至11种。最近在云南省魔芋不同生育期的叶片及茎杆上又发现一种新病害——魔芋疫病。该病水渍状的黑更多还原

【Abstract】 A new blight disease was found on konjac and caused severity loss in Fuyuan County,a main konjac production area in Yunnan.The purified isolates were determined for pathogenicity with Koch’ s postulates and sequenced based on two targets,ribosomal DNA-ITS and Cox2.The phylogenetic relationships between the pathogen and Phytophthora species were also analyzed.The results showed that the isolates were the new pathogen of konjae.The pathogen formed white colony on clarified V8 agar and the hypha were observed without septum,producing spherical chlamydospores and forming ovoid or obpyriform sporangia with obvious papillate.Both DNA sequences of rDNA-ITS and Cox2 from the pathogen shared the highest similarity and had99%homology with known Phytophthora nicotianae.The phylogenetic tree also showed both the pathogen and P.nicotianae were clustered in the same sub-group.These results confirmed that the pathogen caused blight disease on konjac was P.nicotianae.According to our knownledge,this is the first report of new host of P.nicotianae and new disease of konjac.更多还原