To study the symptoms of fire blight of'Korla fragrant pear'and the biological characteristics of pathogenic bacteria,and to provide a theoretical basis for the prevention and control of fire blight of'Korla fragrant pear'.In 2021-2022,the field symptoms of pear fire blight were observed,and the pathogenic bacteria was isolated.The culture characteristics were observed on NA and LB medium,and the morphological characteristics were observed by scanning electron microscopy and transmission electron microscopy.16S rDNA and pEA29 plasmid gene fragments were used to analyze the regulatory mechanism of pathogenicity at molecular level,and the pathogenicity of leaves and young fruits were determined by acupuncture method.The results showed that the main symptoms of fire blight in'Korla fragrant pear'include black death in inflorescences,black death in young fruits,dead tips,black veins,dead branches,necrosis of short branches,bacterial pus and ulceration.The pathogenic bacteria generally invade the tree from the inflorescence,and gradually infect other healthy plant tissues.The next year,the tree carries the bacteria and causes the disease of the branches from the inside out.Morphological observation of pathogenic bacteria revealed that the colonies were white,with neat edges and circular shapes.The bacterial bodies were short rod-shaped,mainly solitary,with the size of 0.4～1.2 μm×0.9～1.9 μm.Building a phylogenetic tree revealed that TDXL and Erwinia amylovoraclustered on the same branch.Leaves and young fruits inoculated with pathogens can cause disease and bacterial pus.Through morphological observation and phylogenetic tree construction,E.amylovora was identified as the pathogen causing fire blight of'Korla fragrant pear'.
关键词
库尔勒香梨/梨火疫病/危害症状/病原菌鉴定/梨火疫病病原菌
Key words
'Korla fragrant pear'/fire blight of pear/harmful symptoms/identification of pathogenic bacteria/Erwinia amylovora
维普
万方数据