葛慈斌 黄素芳 阮传清 肖荣凤 刘韬

摘 要：【目的】明确引起福建建阳桔柚落叶、枝梢枯死的两种病害的病原菌种类，为防治病害提供基础。【方法】从建阳桔柚上采集典型发病叶片，进行病原菌的分离、形态观察和菌株rDNA-ITS 区序列比对、致病性测定。【结果】桔柚病叶片中分离出两种主要病原真菌，代表菌株分别为FJAT-32214和FJAT-32151。菌株FJAT-32214在PSA培养基上的菌落颜色为灰褐色，产褐色分生孢子，多呈链状分隔，其rDNA-ITS区序列与互隔交链孢霉Alternaria alternata的ITS序列相似性达99%;菌株FJAT-32151在PSA培养基平板上的菌丝呈灰白色，绒状、茂密，后期会在菌落表面产生砖红色孢子堆，分生孢子柱形或棒状，单胞，无色， 其rDNA-ITS区序列与胶孢炭疽菌Colletotrichum gloeosporioides 的ITS序列相似性也达99%，通过回接可引起样本致病，分离获得与接种物一致的病原物，符合Koch氏法则。【结论】通过病原形态学与ITS序列分析，鉴定了发生在建阳桔柚叶片上的两种主要真菌性病原，分别为引起褐斑病的互隔交链孢霉和炭疽病的胶孢炭疽菌。

关键词： 建阳桔柚;病害鉴定;互隔交链孢霉;胶孢炭疽菌

中图分类号：S 687文献标识码：A文章编号：1008-0384（2019）08-958-07

Abstract：【Objective】 To identify the pathogens of the severe defoliation and dieback diseases on Jianyang tangelos. 【Method】 Leaf specimens were collected from the diseased tangelo plants in Jianyang city. Microbial strains were isolated for morphological observation， pathogenicity determination， and sequence analysis on internal transcribed spacer （ITS） of ribosomal DNA for taxonomic identification. 【Result】 Separately， two strains were considered the pathogens for the diseases. The FJAT-32214 strain formed grayish brown colonies on a PSA medium and produced brown septate spores. Its rDNA-ITS sequences showed a 99% similarity with that of Alternaria alternata from NCBI. The other strain， FJAT-32151， formed on PSA gray-white， velvety， dense colonies with brick-red spore piles on the surface in late stage and produced columnar or rod-like， unicellular， colorless spores. The rDNA-ITS sequence of FJAT-32151 was 99% homologous with that of Colletotrichum gloeosporioides. Each of these isolated strains met Koch requirement with a challenge test by inoculation on healthy plants to show the typical morphological characteristics of the respective fungal disease. 【Conclusion】 It was confirmed that A. alternata was the pathogen that caused the brown spots disease， and C. gloeosporioides the anthracnose disease on the tangelos.

Key words：Jianyang tangelo; disease diagnosis; Alternaria alternata; Colletotrichum gloeosporioides

0 引言

【研究意義】建阳桔柚是由福建省建阳市农业开发公司于20世纪80～90年代在从日本引进的甜春桔柚基础上，通过优良变异单株选育而成的杂柑类品种[1]，是建阳市具有地方特色的名优水果和主要经济作物，于2009年11月获国家地理标志产品保护。建阳桔柚果大质优，既有桔子的清香，又具柚子的脆甜，色泽金黄、汁多肉脆、清香爽口[2]，是医药、食品工业的重要原料;其果实性凉味甘，有生津止咳、润肺化痰、理气健胃、散结止痛、醒酒利尿等多种功效，在省内外享有声誉。……