中粒种咖啡新发砖红镰刀叶枯病病原菌鉴定及其病原生物学分析

针对引起海南省白沙农场中粒种咖啡成株叶片呈砖红色枯萎症状的一种未知病害的病原菌进行分离,分离得到菌株21BS02-1和21BS02-2。将分离菌株接种到叶片并观察症状,发现菌株21BS02-1的发病症状与田间症状一致,通过再分离获得的菌株发病症状也与初始病原菌症状一致,由此确定菌株21BS02-1即为致病菌。菌株21BS02-1的菌落主要呈白色,毡状,菌丝致密,菌落中央呈玫瑰色;其菌丝体细长,部分菌丝为有隔菌丝;大型分生孢子两端稍弯曲,形状似镰刀,其大小为(56.26~175.76)μm × (12.93~19.78)μm,有3~7个分隔;小型分生孢子较少,呈椭圆形,0~1个分隔;根据形态特征初步鉴定该病原菌为镰刀菌（Fusarium sp.）。进一步对菌株21BS02-1的ITS、β-tubulin、TEF基因序列进行克隆测序,经Blast搜索表明,其ITS、β-tubulin、TEF序列与Fusarium lateritium的同源性分别达到99.56%（MN686293）、100%（KJ00154）、99.68%（KF918550）。3个单基因聚类树均一致,表明菌株21BS02-1属于砖红镰刀菌（F. lateritium）。生物学特性测定表明,致病菌21BS02-1最适合的培养基为OMA和CMA培养基;碳源为蔗糖时的利用率最高;牛肉浸膏为致病菌最适生长的氮源;12 h光暗交替条件下菌丝生长最快;pH在7~9范围内最适合该致病菌生长。本研究是砖红镰刀菌（F. lateritium）侵染中粒种咖啡较为详细的报道。

Identification and Biological Analysis of Fusarium lateritium Causing Leaf Blight Disease on Coffea canephora

An unknown disease on Coffea canephora which caused the leaves to become brick-red and withered in a farm of Baisha County, Hainan Province was studied. Two pure cultures 21BS02-1 and 21BS02-2 were isolated. The isolates were inoculated into the leaves and the symptoms were observed. It was found that the symptoms of 21BS02-1 were similar to the field symptoms, and the re-isolate was also consistent with the original pathogen. Therefore, strain 21BS02-1 was determined to be the pathogen. The colony of strain 21BS02-1 was mainly white, felt, dense hyphae, and the color of the center colony was rose. Its mycelia were slender, and some mycelia were septate mycelium. The two ends of macroconidia were slightly curved and shaped like a sickle, with a size of (56.26-175.76)μm × (12.93-19.78)μm, and there were 3-7 partitions. There were few microconidium, which were mainly elliptical and with 0-1 partition. According to the morphological characteristics, the pathogen was preliminarily identified as Fusarium sp. Then through internal transcribed spacer (ITS), β-tubulin and TEF genes to identify the pathogen, BLAST indicated that the homology with Fusarium lateritium of each gene sequence was 99.56% (MN686293), 100% (KJ00154), 99.68% (KF918550), respectively. The three single gene cluster trees based on ITS, β- tubulin, and TEF gene sequence showed that 21BS02-1 belonged to F. lateritium. The determination of biological characteristics showed that the most suitable medium for 21BS02-1 was OMA and CMA medium. The most suitable carbon source was sucrose, and the utilization rate was the highest. Beef extract was the most suitable nitrogen source. The mycelia growth was the fastest under the condition of alternating light and dark for 12 h, and pH value 7-9. This is the first detailed report of F. lateritium infecting C. canephora.