梨火疫病菌在库尔勒香梨枝条中的侵染定殖和扩展特征研究  

Characterization of the infectious colonization and expansion with GFP tagged strain of Erwinia amylovora in Kuerlexiangli pear(Pyrus sinkiangensis Yu) shoots

作　　者：吕天宇 徐琳赟 席海珅 韩剑[1,2] 罗明 LÜTianyu;XU Linyun;XI Haishen;HAN Jian;LUO Ming(College of Agriculture,Xinjiang Agricultural University/Key Laboratory of Detection and Prevention and Control of Agricultural and Forestry Pests,Urumqi 830052,Xinjiang,China;Key Laboratory of Prevention and Control of Invasive Organisms in Northwest Desert Oasis Agriculture and Forestry,Ministry of Agriculture and Rural Affairs,Urumqi 830052,Xinjiang,China)

机构地区：[1]新疆农业大学农学院·农林有害生物检测与防控重点实验室,乌鲁木齐830052 [2]农业农村部西北荒漠绿洲农林外来入侵生物防控重点实验室,乌鲁木齐830052

出　　处：《果树学报》2023年第8期1692-1702,共11页Journal of Fruit Science

基　　金：新疆维吾尔自治区自然科学基金重点项目(2021D01D12);国家重点研发计划(2021YFD1400200);新疆维吾尔自治区重大科技专项(2019A01001-2)。

摘　　要：【目的】示踪梨火疫病菌Erwinia amylovora在库尔勒香梨(Pyrus sinkiangensis Yu)(简称香梨)枝条组织中侵染定殖和扩展特征,为梨火疫病的有效防治提供依据。【方法】以分离获得梨火疫病强致病力菌株E.a001为材料,采用热激法将携带有绿色荧光蛋白基因(green fluorescent protein,GFP)质粒phc60-gfp转化E.a001,获得了能发出强烈绿色荧光的标记菌株E.a001-gfp。利用该标记菌株接种香梨枝条,检测、观察其在香梨枝条组织中的侵染定殖和扩展动态。【结果】针刺接种和喷雾接种E.a001-gfp引起枝条发病的最低浓度分别为106cfu·mL^(-1)和107cfu·mL^(-1)。相同浓度的病原菌接种,喷雾接种较针刺接种后发病显症时间延迟2~3 d。梨火疫病菌侵染枝条产生的坏死病斑的扩展速率随病原菌浓度提高而升高;病菌在1年生枝条上的生长扩展速度显著快于在2年生枝条内的扩展速度。梨火疫病菌入侵后主要存在于枝条维管系统中,大量分布于皮层薄壁细胞和韧皮部薄壁细胞间隙,少量存在于木质部导管中。在香梨发病枝条上,病健交界处的活菌数量最高,可达到108cfu·g^(-1),未显症部位0~10 cm处病原菌为105cfu·g^(-1),但在香梨枝条病斑外未显症部位10~15 cm处均未分离出病原菌。【结论】研究明确了梨火疫病菌在香梨枝条组织中的扩展距离、迁移时间及速率,以及分布及定殖量,为病枝的准确修剪和制定病害的综合防控措施提供了科学依据。【Objective】Fire blight is a major international quarantine bacterial disease caused by Erwinia amylovora,a destructive bacterium that infests pears,apples and other kinds of rosaceae nut fruit trees.In 2016 and 2017,it was found for the first time in Yili and Bazhou in Xinjiang,China,harming pear,apple,hawthorn,begonia,quince and other fruit trees,especially spreading extremely fast on Kuerlexiangli pear(Pyrus sinkiangensis Yu),resulting in severe economic loss to the pear industry.The infestation characteristic that E.amylovora can transfer rapidly in the host tissues is an important reason for the fast epidemic speed,destructive damage and great difficulty of control.Timely pruning of diseased fruit trees can not only greatly reduce the amount of pathogenic bacteria,but also prevent its migration and expansion in the tree,which is an important measure for disease prevention and control and easy to implement and cost-effective.The artificial inoculation of tracing pathogenic bacteria in pear branch tissue infestation colonization and migration characteristics was employed to deeply understand the pathogenic bacteria in the host tissue infestation expansion process and mechanism in order to guide the field pruning of diseased branches,disease resistant varieties selection and breeding and the development of integrated control measures【Methods】In this study,the virulent pathogenic strain E.a001 was isolated the shoots infested by fire blight,and the Green Fluorescent Protein(GFP) plasmid phc60-gfp was transformed into E.a001 by thermal excitation method,and the strong green fluorescent strain E.a001-gfp was successfully obtained.The inoculations of different concentrations of E.a001-gfp suspension were conducted with two methods,needle prick and spray,to detect and observe the dynamics of infestation and expansion in the tissues of pear shoots.【Results】The GFP-labeled E.a001-gfp strain emitted strong green fluorescence under fluorescence microscopy,and a target fragment of about 700 bp was amplified fr

关 键 词：库尔勒香梨 梨火疫病菌 绿色荧光蛋白基因标记 侵染 扩展 

分 类 号：S661.2[农业科学—果树学]