娄德钊 武华周 卢芙萍 耿涛 涂娜娜 王树昌

摘  要：桑树青枯病是由青枯雷尔氏菌引起的细菌性病害，热带、亚热带地区发病严重，严重影响蚕桑产业的可持续发展。雷尔氏菌不同种间致病力和宿主各不相同，其防治策略也相应不同，准确地分离鉴定病原菌是青枯病有效防控的先决条件。本研究采集、分离了海南省琼中县桑青枯病发病桑园（‘桂桑优62’）桑树根部、茎部病原菌，并通过致病性、生理小种、生化变种测定，结合16S rDNA、特异性引物、复合PCR检测体系、序列变种等分子鉴定方法初步确定了病原菌的种类和分类地位。结果表明，引发海南省琼中县桑青枯病的病原菌属于青枯雷尔氏菌（Ralstonia solanacearum）、生理小种5（race 5）、生化变种Ⅴ（biovar Ⅴ），病原菌遗传进化分析结果显示病原菌属演化型Ⅰ（phylotype Ⅰ）即亚洲分支菌株，序列变种12（sequevar 12）。这些结果将为海南桑青枯病的有效防控奠定基础。

关键词：桑树青枯病;病原鉴定;雷尔氏菌;分子鉴定;系统发育

中图分类号：S888.71     文献标识码：A

Abstract： Bacterial wilt of mulberry is a bacterial disease caused by Ralstonia solanacearum. It is serious in tropical and subtropical areas， which restricts the development of sericulture industry. The pathogenicity and host of R. solanacearum are different from each other， and the control strategy is also different. Accurate isolation and identification of the pathogen is the prerequisite for the effective control of bacterial wilt. In this study， we collected and isolated the pathogenic bacteria of mulberry （‘Guisangyou 62’） in Qiongzhong County， Hainan Province. The strains were selected and tested for pathogenicity， race and biovar， combined with 16S rDNA molecular identification， specific primers， multiplex PCR detection system and sequence variation， and with phylogenetic analysis. All the three strains were R. solanacearum. According to the traditional classification the pathogen belongs to physiological race 5 and biovar V. The genetic evolution of the pathogen was further analyzed by molecular biology methods. The pathogen belonged to phylotype I （the Asiaticum division）， sequevar 12. The results would lay a foundation for the effective control of mulberry bacterial wilt in Hainan.

Keywords： Morus alba L. bacterial wilt; pathogen identification; Ralstonia solanacearum; molecular identification; phylogeny

DOI： 10.3969/j.issn.1000-2561.2021.11.027

桑樹（Morus alba L.）是一种重要的经济作物，桑叶、桑葚、桑根、桑枝均可入药，桑叶不仅是家蚕饲料，而且可以制成桑茶、桑叶菜、桑叶粉及桑叶饮料等，被列入“既是食品又是药品的物品”名单。桑树种植面积广，朝鲜、日本、蒙古、中亚各国、欧洲、东南亚等地以及非洲均有栽培。桑树栽培起源于中国，长期以来种植于我国长江、黄河中下游地区;随着“东桑西移”“北桑南移”，我国桑蚕重心逐渐向亚热带和热带地区发生转移[1]。海南岛地处108°37′～ 118°03′ E，18°10′～20°10′ N，气候属热带季风季候，年平均气温22 ℃～26 ℃，年均降水量2000～2400 mm，桑树全年生长，与其他地区相比，海南的蚕桑产业拥有得天独厚的地理优势[1]，近年来种植面积不断扩大[2]。……