洛阳核桃黑斑病病原菌鉴定

<正>0引言核桃黑斑病是核桃的三大主要病害之一，发病范围广，危害严重，一般植株受害率70%～90%，果实受害率10%～40%，严重时达65%以上，导致核桃栽培经济效益大幅降低^1]。核桃黑斑病病菌在病枝、芽鳞和残留的病果等处越冬，从气孔、皮孔、柱头、伤口等处侵入，借雨水、花粉、昆虫传播，可多次侵染^2]。

Identification of the pathogen of walnut black spot in Luoyang

In order to explore the pathogenic bacteria of walnut black spot in Luoyang, a field survey was carried out in Luoyang walnut orchard in 2020, typical disease samples were collected, and the pathogenic bacteria were isolated by tissue separation method. After purification and culture, the pathogens were connected to healthy leaves by acupuncture method, and the pathogenicity was tested and Koch′s rule was verified. The isolated strain YSYB was identified by morphological characteristics, physiological and biological identification, and the results showed that the strain YSYB was very similar to Pantoea. Using the total DNA of the strain as a template, the 16S rDNA universal primer was used for PCR amplification. Agarose gel electrophoresis showed a fragment of about 1 500 bp in length, and sequencing results showed that the amplified 16S rDNA fragment was 1 450 bp in length. The results showed that the 16S rDNA sequence of strain YSYB was 100% similar to Pantoea agglomerans by comparison with the known sequence in GenBank, and the phylogenetic tree was clustered into the same branch. The results showed that the pathogen was P. agglomerans.