一株新的引起玉米细菌性茎腐病病原细菌的分离鉴定

Isolation and identification of a new pathogenic bacterium causing bacterial stalk rot of maize

玉米茎腐病是一种在世界玉米产区普遍发生的土传病害,根据病原菌的不同,玉米茎腐病分为细菌性茎腐病和真菌性茎腐病。玉米细菌性茎腐病病原主要有短小芽孢杆菌(Bacillus pumilus Meyer and Gottheil)^([1])、玉米狄克氏菌(Dickeya zeae Samson et al.)^([2])、铜绿假单胞杆菌(Pseudomonas aeruginosa)^([3])、成团泛菌(Pantoea agglomerans)^([4])等。

In 2019,the disease was observed in the maize growing areas of Dehong County,Yunnan Province,China.On the basis of signs and symptoms,the disease was characterized as a bacterial infection.Identification of the pathogen were based on morphological characteristics,biology and physiological and biochemical assay,16 S rDNA and specific rpoD and gapA gene sequence analysis.The results show that the pathogen is similar to short rod in shape under a transmission electron microscope,the both ends are obtuse and have 1-3 terminal flagella.In King’s B medium,it produced milky white,round,smooth surface and transparent edge colonies and can utilize the 58 kinds of carbon sources.The LOPAT test result is"+++-+".The construction of evolutionary trees was based on the 16 S rDNA、rpoD and gapA gene sequencing,which indicated the closest genetic relationship with Pseudomonas extremorientalis and which was finally identified as P.extremorientalis.To our acknow-ledgment,this is the first report on the bacterial stalk rot disease of maize caused by phytopathogenic bacteria P.extremorientalis.