一株可诱导海带配子体产生白化病的细菌的分离与鉴定  

Isolation and identification of a pathogenic bacterium causing bleaching disease in the gametophytes of Saccharina japonica

作　　者：韩宜晓 任艺飞 庄英瑞 陈尧 钟秋连[1,2] 邱其樱 陈德福 王高歌 HAN Yi-xiao;REN Yi-fei;ZHUANG Ying-rui;CHEN Yao;ZHONG Qiu-lian;QIU Qi-ying;CHEN De-fu;WANG Gao-ge(College of Marine Life Sciences,Ocean University of China,Qingdao 266003,China;Institute of Evolution&Marine Biodiversity,Ocean University of China,Qingdao 266003,China;Fujian Lianjiang Guanwu Seafood Developing Product Co.,Ltd.,Guanwu 350511,China)

机构地区：[1]中国海洋大学海洋生命学院,山东青岛266003 [2]中国海洋大学海洋生物多样性与进化研究所,山东青岛266003 [3]福建省连江官坞海产开发有限公司,福建官坞350511

出　　处：《海洋科学》2023年第7期53-64,共12页Marine Sciences

基　　金：国家自然科学基金项目(41576158,42076106);中国海洋大学大学生创新训练项目(202110423183X)。

摘　　要：海带(Saccharina japonica)是一种重要的经济养殖海藻。中国海带与褐藻胶的产量分别占世界总产量的60%和90%。与高等农作物相似,在海带育苗及养殖过程中常常会暴发病害,严重时可造成20%~50%的减产。分离、鉴定致病菌及其致病因子是预防和控制病害发生的前提条件。由于海藻的致病菌大多是条件致病菌,迄今为止,海带致病菌的分离和鉴定仍是一个瓶颈问题。本研究运用传统微生物分离培养方法从脱苗病海带幼苗藻体分离出一株致病菌LJ2-4,经过复染实验及科赫法则验证,证实该菌株在实验室条件下可使健康海带雌、雄配子体产生白化的病症。LJ2-4菌落圆形、边缘完整,呈浅橙色。扫描电镜和透射电镜观察表明:LJ2-4菌体呈球形/杆状,长0.5~1.2μm,宽0.4~0.7μm无鞭毛。经16S rDNA分子鉴定,其与Planococcus okeanokoites IFO 12536^(T)的相似性为99.45%。结合LJ 2-4的生理生化特性,将该菌株命名为Planomicrobium okeanokoites LJ2-4。P.okeanokoites LJ2-4是在实验室条件下可引起健康海带配子体产生白化病的条件致病菌。本研究为海带致病菌致病机理的研究奠定了前期工作基础,同时也可为预防与控制海带苗期脱苗病的暴发提供理论依据。Saccharina japonica is an economically important seaweed worldwide.China contributes to 60%of seaweed production and 90%of alginate globally.Similar to high crops,disease outbreaks in seaweeds often occur during the nursery and field cultivation stages,causing a 20%-50%reduction in yield in severe cases.The isolation and identification of pathogenic bacteria and the factors responsible for their pathogenicity are prerequisites for the prevention and control of diseases.Because the pathogenic bacteria of seaweed are primarily opportunistic,isolating and identifying the bacteria responsible for diseases in cultivated S.japonica is a challenge.In this study,a strain of the pathogenic bacterium LJ2-4 was isolated from the falling-off diseased sporelings by the traditional culture-dependent method.Using the reinfection assay and Koch’s postulates,it was observed that LJ2-4 caused the bleaching disease in healthy male and female gametophytes of S.japonica under laboratory conditions.LJ2-4 was Gram positive and appeared light orange in color.Scanning electron microscopy and transmission electron microscopy indicated that LJ2-4 was coccus or rod-shaped,lacking flagella,and approximately 0.5-1.2μm in length and 0.4-0.7μm in width.Blasting the sequence of 16S rDNA revealed that LJ2-4 shared 99.45%similarity with Planococcus okeanokoites IFO 12536^(T).Therefore,combining the physiological and biochemical characteristics of LJ2-4,we designated it as Planomicrobium okeanokoites LJ2-4.This study lays the foundation for investigating the mechanisms underlying the S.japonica pathogens and provides a theoretical reference for preventing and controlling the falling-off disease at the nursery stage of S.japonica.

关 键 词：海带 脱苗病 致病菌 Planomicrobium okeanokoites LJ2-4 

分 类 号：S946[农业科学—水产养殖]