采后莲雾果实软腐病病原菌的分离鉴定和拮抗菌的筛选及防治机理

Isolation and Identification of Soft Rot Pathogen in Postharvest Wax Apple,Screening of Its Antagonistic Strain and Prevention Mechanism

目的:以采后“大叶”莲雾为对象,对其病原菌进行分离及鉴定,筛选病原菌拮抗菌,并对其拮抗机理进行初步探究。方法:通过组织分离法得到引起莲雾果实软腐病的病原菌,采用平板对峙法筛选出拮抗菌,对病原菌、拮抗菌进行形态学和分子生物学鉴定。通过空间竞争和抗病相关酶活性测定探究其机理。结果:莲雾软腐病病原菌鉴定为小孢拟盘多毛孢(Pestalotiopsis microspora)。针对病原菌分离出拮抗菌143株,效果最明显的菌株命名为D-1,其抑菌圈直径达11.10 mm,鉴定为沙福芽孢杆菌(Bacillus safensis)。体内实验结果表明,拮抗菌D-1可有效抑制莲雾软腐病病斑的扩展,明显降低果实发病率,并且其能在果实伤口处快速定殖形成空间竞争。而且,D-1可明显提高果实抗病相关酶苯丙氨酸解氨酶、过氧化物酶和多酚氧化酶的活性,从而提高果实的抗病能力。

Objective:Wax apple fruits(cv.Daye)were used to isolate pathogen which could cause soft rot disease of the fruit,its antagonistic microorganisms were screened and the mechanism of antagonism was explored.Methods:Conventional tissue separation method was applied to separate disease tissue.And the antagonistic microorganisms were screened by the flat-stand method.The pathogen and antagonistic microorganisms were identified by morphological and molecular biological methods.The mechanism was explored by spatial competition and resistance-related enzyme activity assays.Results:A total of 143 antagonistic strains were isolated.The strain which had the most obvious effect was named D-1,of which the diameter of bacteriostatic circle was 11.10 mm and the strain was identified as Bacillus safensis.In addition,in vivo test showed that antagonistic strain D-1 could effectively inhibit the development of lesions and reduce the disease incidence,it could colonize quickly at the wound to present space competition with pathogen.Furthermore,D-1 significantly increased the activity of phenylalanine ammonia lyase,peroxidase and polyphenol oxidase,and improved disease resistance against soft rot of wax apple fruit.