苦瓜平脐蠕孢叶斑病病原鉴定

<正>苦瓜是葫芦科苦瓜属植物,在亚洲热带地区、东非、加勒比海等地区均有种植,是药食兼用的重要蔬菜,也是广西南菜北运的主要蔬菜品种~([1,2])。据农业部门不完全统计,广西苦瓜的生产面积超过1.6万公顷,且逐年有增加的趋势。近年来,随着气候的变化,作物栽培面积的扩大,病害的发生也在不断增加。     

青苹果竹芋平脐蠕孢叶斑病病原菌的鉴定

A new leaf spot disease on Calathea rotundifolia cv. fasciata was observed in Guangdong, China. The pathogen of this disease was identified by pathogenicity, morphological characteristics and multi-gene sequences analysis of ITS, TEF and GAPDH. The result showed that leaf spot of C. rotundifolia cv. fasciata was caused by Bipolaris sivanesaniana. This is the first report of leaf spot disease on C. rotundifolia cv. fasciata caused by B. sivanesaniana.The results of host range determination showed that B. sivanesaniana could also infect Calathea veitchiana and cause leaf spot. This study will facilitate the timely detection and management of Bipolaris leaf spot.     

引起甜樱桃叶斑病的葡萄座腔菌的鉴定

Cherry leaf spot disease is one of the most common diseases of sweet cherry. In 2018 and 2019, a leaf spot symptom was observed on sweet cherry in Beijing city, Shandong province and Liaoning province, and the pathogen fungi were isolated from diseased samples. Seven fungal isolates (JZB310197-JZB310203) were identified as Botryosphaeria dothidea according to morphological characteristics and multi-gene (ITS, EF 1-α and TUB2) phylogenetic analysis. To fulfill the Koch′s postulation, pathogenicity assay was carried out on detached leaves and tissue cultured seedlings. The inoculation results showed that all isolates were pathogenic to cherry leaves, proving that B. dothidea was a pathogen of cherry leaf spot disease. This is the first report of B. dothidea causing leaf spot of sweet cherry in China.     

苦瓜枯萎病菌过氧化氢酶基因FoCat1致病功能分析

 由尖孢镰孢菌苦瓜专化型(Fusarium oxysporum f.sp.momdicae Sun &Huang)引起的苦瓜枯萎病是一种严重影响苦瓜生产的土传维管束病害。本研究利用分割标记的方法构建FoCat1基因的敲除片段,通过PEG介导的原生质体转化方法对FoCat1基因进行敲除,经4对引物验证得到1个阳性转化子ΔFoCat1-3。突变体ΔFoCat1-3在PDA培养基上的菌落大小、菌丝形态、产孢量等生物学特性与野生型相比均无显著性差异,但是其抵抗外源氧胁迫的能力明显减弱,对苦瓜的致病力明显下降。DAB染色结果显示,接种突变体的苦瓜叶片中过氧化氢的含量明显高于接种野生型菌株的苦瓜叶片。研究结果表明,FoCat1可能不参与病菌正常营养生长过程的调控,但是具有清除寄主产生的活性氧,来减弱寄主对病原菌的杀伤作用的功能,从而参与病原菌的致病过程。     

苦瓜枯萎病菌过氧化氢酶基因FoCat1致病功能分析

 由尖孢镰孢菌苦瓜专化型(Fusarium oxysporum f.sp.momdicae Sun &Huang)引起的苦瓜枯萎病是一种严重影响苦瓜生产的土传维管束病害。本研究利用分割标记的方法构建FoCat1基因的敲除片段,通过PEG介导的原生质体转化方法对FoCat1基因进行敲除,经4对引物验证得到1个阳性转化子ΔFoCat1-3。突变体ΔFoCat1-3在PDA培养基上的菌落大小、菌丝形态、产孢量等生物学特性与野生型相比均无显著性差异,但是其抵抗外源氧胁迫的能力明显减弱,对苦瓜的致病力明显下降。DAB染色结果显示,接种突变体的苦瓜叶片中过氧化氢的含量明显高于接种野生型菌株的苦瓜叶片。研究结果表明,FoCat1可能不参与病菌正常营养生长过程的调控,但是具有清除寄主产生的活性氧,来减弱寄主对病原菌的杀伤作用的功能,从而参与病原菌的致病过程。     

越南槐圆斑病病原鉴定

The pathogen causing round leaf spot of Sophora tonkinensis (Lour.) was identified by Koch's postulates, morphological characteristics and combined gene sequences analysis on ITS, TUB, and ACT. The results showed that morphological characteristics of a pathogenic representative isolate SDG-1 was similar to that of Didymella glomerata. The isolate SDG-1 was clustered into one clade in phylogenetic tree with D. glomerata. Taken together, these results indicated that the round leaf spot of S. tonkinensis was caused by D. glomerata. This is the first report of a round leaf spot on S. tonkinensis was identified as D. glomerata.     

北京市月季丽赤壳褐斑病病原菌鉴定

In September 2018, a new leaf spot on Rosa chinensis with incidence of up to 60% was observed in a park in Miyun district of Beijing. Disease samples were collected and three strains (JZB3210001, JZB3210002 and JZB3210003) were obtained by isolation and single spore purification. According to the morphological characteristics, they were identified as Calonectria sp.. For molecular phylogenetic analysis, β-tub, Cal, H3, EF1-α genes were amplified with genomic DNA of these three isolates. Phylogenetic trees constructed by the Maximum likelihood method showed that three strains clustered with Calonectria blephiliae CBS136425 as a distinct clade with 91% bootstrap support. Based on both morphological characteristics and phylogenetic analysis, the three strains were identified as C. blephiliae. The pathogenicity assay confirmed that C. blephiliae was the pathogen causing this disease. This is the first report of leaf spot caused by C. blephiliae on Rosa chinensis in China.     

华重楼斑枯病病原鉴定

 2018年,四川汶川县重楼种植区的华重楼出现一种新的病害—华重楼斑枯病,该病害主要危害叶片,发生率为35%,天气适宜时可引起整株叶片枯死。为鉴定引起四川汶川县华重楼斑枯病的病原菌,本试验采用组织分离法对病原菌进行分离,利用科赫氏法则验证其致病性,依据菌株的形态学和基于rDNA-ITS和RPB2基因序列分析对病原菌进行鉴定。结果表明,分离菌株的菌落形态、分生孢子器和分生孢子形态与Didymella sp.相似;经分子生物学鉴定,该菌ITS-RPB2基因序列与亚隔孢壳属D. glomerata(登录号为FJ427013、GU371781)的同源性为100%。因此,将引起重楼斑枯病的病原菌鉴定为D. glomerata。     

南天竹一种新的叶斑病病原菌的分离鉴定

<正>南天竹(Nandina domestica)为小檗科南天竹属,常绿灌木,形态优雅,果实球形鲜红且经冬不落,是赏果观叶的园林绿化植物。南天竹具有重要的药用价值,有“镇咳止喘、兴奋神经、强壮身体”之效[1]。在生长过程中,南天竹叶片易受炭疽病(Colletotrichum)危害[2],也可受叶斑病(Pestalotia microspore)、褐斑病(Cercospora nandinae)、     

黄脉爵床棒孢霉叶斑病病原菌及其生物学特性鉴定

 明确黄脉爵床棒孢霉叶斑病病原菌及其生物学特性,为防控提供理论依据。通过病原菌分离、形态特征观察、致病性测定、rDNA-ITS序列分析、生物学特性及寄主范围测定等研究,证明该病病原菌为山扁豆生棒孢Corynespora cassiicola;菌丝生长及产孢适宜温度20℃~28℃,孢子萌发适宜温度24℃~32℃,菌丝致死温度49℃处理10 min;菌丝生长适宜pH 6~10,产孢适宜pH 4~8,孢子萌发最适pH 8;光暗交替适合菌丝生长与产孢,连续光照可抑制菌丝生长;菌丝生长量由少到多培养基顺序为CA、PCA、PDA、CMA、OA,而PDA上产孢最多;刺伤接种,病菌可侵染喜树(Camptotheca acuminata)等植物。黄脉爵床棒孢霉叶斑病病原为山扁豆生棒孢C. cassiicola,病菌易产孢,寄主广,潜育期短。该病菌侵染黄脉爵床为首次报道。