橡胶树棒孢霉落叶病(Corynespora leaf fall disease,CLFD)是全球主要植胶国最为严重的叶部病害之一,可造成严重的产量和经济损失,而抗病种质鉴选与创制利用是该病最为有效的防治策略.本研究对云研 277-5×IAN 873、RRIC103×热研 8-79 和云研 277-5×热垦 525 三个杂交组合的 821 份F1 代群体进行了抗棒孢霉落叶病的评价,明确了F1代群体的抗病性水平,并从符合正态分布的 2 个杂交组合中筛选出 32 份候选 F1 代单株进行芽接,再分别利用 3 个亚型的多主棒孢病菌和 2 种评价方法对候选F1 代无性系种苗进行抗病性复筛,最终获得 5 份抗病性较好的F1 代新种质.通过对 5 份抗病新种质防御酶活性的测定,以及抗病相关基因表达特性的分析,进一步证实了 5 份抗病新种质与多主棒孢病菌在侵染过程中的互作关系,明确了其在病原菌接种不同时间段的差异表达特征.本研究为橡胶树棒孢霉落叶病抗病性早期鉴选、抗病种质培育与创制利用提供了很好的种质材料和理论支撑.

The Colletotrichum acutatum species complex possesses a diverse number of important traits, such as a wide host range and host preference, different modes of reproduction, and different strategies of host infection. Research using comparative genomics has attempted to find correlations between these traits. Here, we used multi-locus techniques and gene genealogical concordance analysis to investigate the phylogenetic relationships and taxonomic status of the Colletotrichum acutatum species complex using field isolates obtained from rubber trees. The results revealed that the dominant species was C. australisinense, followed by C. bannaense, while strain YNJH17109 was identified as C. laticiphilum. The taxonomic status of strains YNLC510 and YNLC511 was undetermined. Using whole-genome single nucleotide polymorphism data to analyze population structure, 18 strains of C. australisinense were subsequently divided into four populations, one of which was derived from an admixture of two populations. In addition, the strains LD1687, GD1628, and YNLC516, did not belong to any populations, and were considered to be admixtures of two or more populations. A split decomposition network analysis also provided evidence for genetic recombination within Colletotrichum acutatum species complex from rubber trees in China. Overall, a weak phylogeographic sub-structure was observed. Analysis also revealed significant differences in morphological characters and levels of virulence between populations.

为了解国内主要植胶区炭疽菌复合种菌株对不同杀菌剂的敏感性,采用生长速率法室内测定乐东炭疽(Colletotrichum.ledongense)、 果生刺盘孢(C.fructicola)、 暹罗炭疽(C.siamense)、 版纳炭疽(C.bannanense)、C.laticiphilum、新种群和华南炭疽(C.australisinense)9株胶孢炭疽病菌(C.glocosporioides Penz.)和8株尖孢炭疽菌(C.acutalum Simmons)对8种杀菌剂的敏感性,并在此基础上进行二元复配评价.结果表明:供试的17株橡胶树炭疽病菌对咪鲜胺最敏感、EC50值为0.0011～0.2187 mg·L?1,平均为0.0853 mg·L?1;咪鲜胺、多菌灵、氟硅唑、戊唑醇、己唑醇、咪鲜胺·三唑酮6种药剂对炭疽菌菌丝生长有显著抑制作用,腈菌唑和粉唑醇对病原菌菌丝抑制效果较差;多数以三唑类为代表的麦角甾醇生物抑制剂对病原菌菌丝生长有明显的抑制效果,尖孢复合种内的新种群对粉唑醇、腈菌唑觉和多菌灵3种药剂敏感性性差;咪鲜胺与戊唑醇的比例分别在7:3和4:6时对橡胶树炭疽菌优势种群暹罗炭疽和华南炭疽的抑制效果最优.

Colletotrichum australisinense, a member of the Colletotrichum acutatum species complex, is an important pathogen causing rubber tree anthracnose. Genome-wide comparative analysis showed this species complex contains more genes encoding necrosis- and ethylene-inducing peptide 1-like proteins (NLPs) than other Colletotrichum species complexes, but little is known about their necrosis-inducing roles in host. The aim of this study was to analyze NLPs number and type in C. australisinense, and characterize their necrosis-inducing activity in host or non-host. According to phylogenetic relationship, conserved the cysteine residues and the heptapeptide motif (GHRHDWE), 11 NLPs were identified and classified into three types. Five of the eleven NLPs were evaluated for necrosis-inducing activity. CaNLP4 (type 1) could not induce necrosis in host or non-host plants. By contrast, both CaNLP5 and CaNLP9 (type 1) induced necrosis in host and non-host plants, and necrosis-inducing activity was strongest for CaNLP9. CaNLP10 (type 2) and CaNLP11 (type 3) induced necrosis in host but not non-host plants. Substitution of key amino acid residues essential for necrosis induction activity led to loss of CaNLP4 activity. Structural characterization of CaNLP5 and CaNLP9 may explain differences in necrosis-inducing activity. We evaluated the expression of genes coding CaNLP by reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time PCR (qRT-PCR) at different time-points after pathogen infection. It was found that genes encoding CaNLPs with different activities exhibited significantly different expression patterns. The results demonstrate that CaNLPs are functionally and spatially distinct, and may play different but important roles in C. australisinense pathogenesis.

天然橡胶是四大工业原料中唯一的可再生资源,由炭疽病菌侵染引起的橡胶树炭疽病是当前我国橡胶生产上最为严重的两大叶部病害之一.本研究以分离自云南保山的喀斯特炭疽病菌MeCkYN1705为对照,对海南新发炭疽病菌喀斯特炭疽菌HCkHNQZ1736进行抗药性评价.结果表明,菌株HCkHNQZ1736对苯并咪唑类杀菌剂多菌灵表现出高抗药性,EC50达1107.2654μg/mL,而MeCkYN1705的EC50仅为0.0554μg/mL.克隆了菌株HCkHNQZ1736的tub2基因,序列分析发现其所编码的第198个氨基酸位点由谷氨酸(Glu-E)突变为丙氨酸(Ala-A),推测该氨基酸位点突变是导致该菌株产生多菌灵抗性的原因.此外生物学特性测定发现,该菌株最适生长温度为28℃,致死温度为35℃;最适生长pH为6;光暗交替利于菌落生长;果胶、蛋白胨分别为最适碳源和氮源.

Natural rubber is an important industrial raw material and an economically important perennial in China. In recent years, A new leaf fall disease, caused by Neopestalotiopsis aotearoa Maharachch., K.D. Hyde & Crous, has occurred in Indonesia, Malaysia, Thailand, Sri Lanka, and other major rubber planting countries. In May and July of 2020, this disease was first found on 2-year-old rubber seedlings in two plantations located in Ledong and Baisha counties in Hainan Province, China. In the two plantations of approximately 32 ha, 15% of the rubber seedlings had the disease and the defoliation was more than 20%. The infected leaves turned yellow and watery, and dark brown and nearly round lesions of 1-2 mm in diameter were formed on the leaves. When the humidity was high, the center of the lesion was grey-white, and the lesions had many small black dots, black margins and surrounded by yellow halos. When the disease was severe, leaves fell off. To identify the pathogen, leaf tissues were collected from lesion margins after leaf samples were surface-sterilized in 75% ethanol, rinsed with sterile water for three times, and air dried. The leaf tissues were plated on potato dextrose agar (PDA) and incubated at 28°C for seven days. Fungal cultures with similar morphology were isolated from 90% of tested samples and two isolates (HNPeHNLD2001 and HNPeHNLD2002) were used in pathogenicity and molecular tests. Rubber leaves (clone PR107) were inoculated with conidial suspension (106 conidia/ml), and inoculated with PDA were used as the control, Each treatment had 3 leaves, and each leaf was inoculated with 3 spots and incubated at 28oC under high moisture conditions. Five days later, leaves inoculated with conidial suspension showed black leaf spots resembling the disease in the field, whereas the control leaves remained symptomless. The fungal cultures isolated from the inoculated tissues, had identical morphology compared with the initial isolates. Colonies on PDA were 55-60 mm in diameter after seven days at 28°C, with undulate edges, pale brown, thick mycelia on the surface with black, gregarious conidiomata; and the reverse side was similar in color. Black conidia were produced after eight days of culture on PDA. Conidia were fusoid, ellipsoid, straight to slightly curved, 4-septate, ranged from 18.35 to 27.12 μm (mean 22.34 μm) × 4.11 to 7.03 μm (mean 5.41 μm). The basal cells were conic with a truncate base, hyaline, rugose and thin-walled, 4.35 to 6.33 μm long (mean 4.72 μm). Three median cells were doliform, 12.53 to 18.97 μm long (mean 15.26 μm), hyaline, cylindrical to subcylindrical, thin- and smooth-walled, with 2-3 tubular apical appendages, arising from the apical crest, unbranched, filiform, 14.7 to 25.3 μm long (mean 19.94 μm). The basal appendages were singlar, tubular, unbranched, centric, 3.13 to 7.13 μm long (mean 5.48 μm). Morphological characteristics of the isolates were similar to the descriptions of N. aotearoa (Maharachchikumbura et al. 2014). The rDNA internal transcribed spacer (ITS) region, translation elongation factor 1-αgenes (TEF), and beta-tubulin (TUB2) gene were amplified using the primer pairs ITS1/ITS4, EF1-728F/EF1-986R and T1/Bt-2b (Pornsuriya et al. 2020), respectively. The sequences of these genes were deposited in GenBank (ITS Accession Nos.: MT764947 and MT764948; TUB2: MT796262 and MT796263; TEF: MT800516 and MT800517). According to the latest classification of Neoprostalotiopsis spp. (Maharachchikumbura et al. 2014) and multilocus phylogeny, isolates HNPeHNLD2001 and HNPeHNLD2002 were clustered in the same branch with N. aotearoa. Thus, the pathogen was identified as N. aotearoa, which is different from N. cubana and N. formicarum reported in Thailand (Pornsuriya et al. 2020; Thaochan et al. 2020). The Neopestalotiopsis leaf spotdisease of rubber tree (H. brasiliensis) was one of the most serious and destructive leaf diseases in major rubber planting countries in Asia. ( Tajuddin et al. 2020) The present study of leaf fall disease on rubber tree caused byN. aotearoa is the first report in China. The finding provides the basic pathogen information for further monitoring the disease and its control.

白根病是世界范围内橡胶树种植业中的重要病害,目前在中国云南等植胶区零星发生.随着天然橡胶产业的发展,该病在中国大面积发生为害的可能性也在不断增加.在前期橡胶树病害监测的基础上,掌握该病在中国的发生状况,并进一步收集国内外相关研究进展,分析其对橡胶树种植业及相关产业的潜在影响、受害橡胶树寄主收获物的经济重要性、病害在中国主栽区蔓延危害的可能性以及病害田间治理难度等因素,采用有害生物风险性分析方法评估白根病对中国天然橡胶相关产业的安全性,评估结果表明其对相关产业的综合风险值R为2.03,属高度危险.

为明确国内橡胶树尖孢炭疽复合种内不同种的生物学特性及种间差异情况,评价了4个代表性菌株(Colletotrichum bannanense YNML52,C.laticiphilum YNJH17109,C.australisinense GX1655,YNJP162)对不同碳源、氮源的利用情况,以及在不同温度、pH、水活度下的生长情况,并评价了这些菌株对橡胶不同品种和不同作物的致病性.结果 表明:供试菌株在碳源、氮源利用,适宜生长温度、致死温度、pH和水分活度等方面均存在显著差异;致病性分析表明,供试菌株的致病谱也存在显著差异,YNML52的寄主范围较窄,具有很强的寄主专化性.通过评价生态因子对橡胶树炭疽病病原菌生物学特性的影响,为深入了解橡胶病害发生规律和制定有效防控措施提供指导依据.

基于目前橡胶树拟盘多毛孢叶斑病在境外主要植胶国爆发流行的态势,以及对天然橡胶产业经济带来的巨大影响。笔者前期对我国海南、云南、广东等省橡胶主产区的13个农场和胶园进行了病害踏查,在我国海南省乐东县志仲镇乐东保显农场发现了疑似橡胶树拟盘多毛孢叶斑病病样。本研究将该疑似病样病原菌进行分离、纯化和致病力测定,并通过形态学和分子系统学分析,确定该病原菌为新拟盘多毛孢属（Neopestalotiopsis）的Neopestalotiopsis aotearoa Maharachch.,K.D.Hyde ＆ Crous;基础生物学特性分析表明,该病原菌菌丝生长和孢子萌发的适宜温度为28℃,孢子致死温度为50℃;适宜pH为6.5,最适碳源为蔗糖和D-葡萄糖,最适氮源为硝酸钾和大豆蛋白胨;最适培养基为PDA,培养8 d后产孢。初步明确了该病的病原及其基础生物学特性,为提前储备防治该病的相关技术措施提供理论依据。

从云南省临沧市某开割橡胶林中分离到一类以YNLC510为代表的致病炭疽菌,经多基因序列分析结合形态比较后推测其为尖孢炭疽复合种下的一个新类群.基础生物学特性和致病性测定结果表明:YNLC510在28℃、pH 7.0～8.0、以果胶为碳源、大豆蛋白胨为氮源时最适合菌丝生长;在32℃、以果胶为碳源、天冬酰胺、大豆蛋白胨为氮源时产孢量最大;培养基水活度对菌丝生长和孢子形成具有极大影响,当水活度小于0.93 aw.菌丝几乎不再生长,而小于0.99 aw.即不再具备产孢能力;YNLC510对国内当前主栽或主推的橡胶品种均表现致病,对IAN873和GT1的致病性最强,对PB86、PB235和PR107相对较弱;且在无伤条件下能侵染番木瓜、芒果、辣椒和黄瓜的叶片,但不能侵染番石榴叶片和辣椒果实,在刺伤条件下对供试植物均可致病.这是关于该类炭疽的首次报道.当前报道的橡胶树尖孢炭疽复合种中已有3个种仅在云南省内分布,显示出该区域橡胶树上炭疽属真菌存在丰富的种群多样性.

南美叶疫病(SALB)是世界橡胶种植中为害最重的病害.目前,该病仅在拉丁美洲部分地区发生,但随着国际交流的增多,其传入东南亚乃至入侵我国的风险也在不断升高,有必要分析该病入侵我国的风险.在前期监测中国橡胶树病害工作基础上,通过收集国内外相关研究进展,明确该病的分布状况,分析其潜在经济危害性、受害寄主的经济重要性、传播扩散的可能性及危险性管理难度等情况,采用有害生物风险性分析方法进行安全性评估.结果 表明,南美叶疫病对中国橡胶产业的综合风险值R为2.38,属高度危险.

2014年9月至2015年2月,笔者作为中国技术顾问参与了中英非农业合作项目,赴乌干达负责木薯种植方面工作.通过实地考察以及和乌干达农牧渔业部、国家农业研究组织、非洲创新研究所、马克累累大学等相关机构专家的交流,对木薯相关产业进行了初步调研,同时,开展了木薯主产区的病害联合调查,发现花叶病、褐条病、细菌性萎蔫病、褐斑病等为当地主要病害.

由多主棒孢侵染引起的橡胶树棒孢霉落叶病(Corynespora leaf fall disease,CLFD)是世界天然橡胶种植业的第二大病害.该病在中国橡胶树主栽区的苗圃和部分开割树上普遍发生,随时可能爆发成灾.为保障中国天然橡胶及相关产业的健康发展,本研究开展了CLFD安全性评估工作.通过收集国内外有关CLFD的研究成果,综合中国CLFD前期监测结果,明确了该病在国际植胶国和中国植胶区的发生情况,分析了CLFD的潜在经济危害性、受害橡胶树等寄主作物的经济重要性、病害传播扩散的可能性、危险性管理难度等,采用有害生物风险性分析方法进行安全性评估.结果 表明:CLFD对相关产业的综合风险值R为2.30,属于高度危险,建议相关部门加强该病的检测、检疫等研究.

HomePlant DiseaseVol. 103, No. 9First Report of Papaya Anthracnose Caused by Colletotrichum brevisporum in China PreviousNext DISEASE NOTES OPENOpen Access licenseFirst Report of Papaya Anthracnose Caused by Colletotrichum brevisporum in ChinaX. B. Liu, Feng Yanli, Zheng Xiaolan, and G. X. HuangX. B. Liuhttp://orcid.org/0000-0003-1483-3938Environment and Plant Protection Institute, CATAS, Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture, Hainan Key Laboratory for Monitoring and Control of Tropical Agricultural Pests, Haikou, Hainan 571101, P.R. ChinaSearch for more papers by this author, Feng YanliEnvironment and Plant Protection Institute, CATAS, Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture, Hainan Key Laboratory for Monitoring and Control of Tropical Agricultural Pests, Haikou, Hainan 571101, P.R. ChinaSearch for more papers by this author, Zheng XiaolanEnvironment and Plant Protection Institute, CATAS, Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture, Hainan Key Laboratory for Monitoring and Control of Tropical Agricultural Pests, Haikou, Hainan 571101, P.R. ChinaSearch for more papers by this author, and G. X. Huang†Corresponding author: G. X. Huang; E-mail Address: [email protected]Environment and Plant Protection Institute, CATAS, Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture, Hainan Key Laboratory for Monitoring and Control of Tropical Agricultural Pests, Haikou, Hainan 571101, P.R. ChinaSearch for more papers by this authorAffiliationsAuthors and Affiliations X. B. Liu Feng Yanli Zheng Xiaolan G. X. Huang † Environment and Plant Protection Institute, CATAS, Key Laboratory of Integrated Pest Management on Tropical Crops, Ministry of Agriculture, Hainan Key Laboratory for Monitoring and Control of Tropical Agricultural Pests, Haikou, Hainan 571101, P.R. China Published Online:10 Jul 2019https://doi.org/10.1094/PDIS-03-19-0539-PDNAboutSections ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmailWechat Papaya (Carica papaya) is an important fruit crop grown in tropical and subtropical regions of China. Anthracnose is an economically important papaya disease and is widely distributed in China. The prevalence of anthracnose causes losses of 20 to 50%. Previously, it has been shown that this disease was caused by C. gloeosporioides in China (He et al. 2010). Papaya (cv. Rising) plants showing anthracnose symptoms were observed during surveys of disease in Hainan province in 2017. The acreage of plantation was 5 acres. The percentage of symptomatic plants was about 60%. The infected leaves showed typical anthracnose symptoms: dark brown lesions with black margins and surrounded by a yellow halo. Small pieces of necrotic tissue were surface sterilized for 1 min in 1.5% NaOCl, washed twice using sterile distilled water, and plated onto potato dextrose agar (PDA). The plates were incubated at 28°C for 3 to 5 days. Two pure cultures of isolate were obtained by subculturing onto fresh PDA plates. Identification of isolates was based on morphological and molecular characterization. Morphology characteristics of isolates were observed after growth on PDA at 28°C under dark for 7 days. Colonies varied between white and dark brown in reverse, and the mycelial growth rate was 15 mm per day. Conidiophores were hyaline to pale brown, branched. Conidiogenous cylindrical to ampulliform, straight to flexuous, 15 to 35 μm. Conidia were hyaline, aseptate, cylindrical with round ends, smooth-walled, guttulate, 11 to 18 × 4.5 to 6 μm, mean ± SD = 14.5 ± 2.2 × 5.1 ± 0.4 μm (30 conidia). Partial sequences of ACT, GAPDH, TUB2, and ITS gene were sequenced to accurately identify the species. Sequences of the isolate obtained in this study were deposited in GenBank (ITS accession nos., MH311772 and MK032210; TUB2, MH311773 and MK032213; GAPDH, MH311774 and MK032211; ACT, MH311775 and MK032212). ITS (502 bp) of the papaya isolate was 100%, and ACT (1/222 bp), GAPDH (2/201 bp), and TUB2 (2/697 bp) were more than 99% similar with ex-type culture BCC38876 of Colletotrichum brevisporum (GenBank accession nos. JN050238, JN050216, JN050227, and JN050244) (Noireung et al. 2012). Based on morphological and multilocus phylogeny, the papaya isolates CPDZ21 and CPDZ23 were identified as C. brevisporum. Cultures from this study were deposited in the China General Microbiological Culture Collection (CGMCC3.19220 and CGMCC3.19221). Pathogenicity testing was conducted with two strains of C. brevisporum on detached papaya (cv. Rising) leaves and fruits. Healthy leaves and fruits were surface sterilized by using 1% sodium hypochlorite and sterilized water and then were inoculated using the wound/drop (106 conidia/ml) and nonwound/drop inoculation methods. Leaves and fruits inoculated with sterile water were used as a control. Inoculated leaves and fruits were maintained in a humid chamber at 25°C in the dark. After 5 days typical anthracnose symptoms were observed on the leaves and fruits. Fruits affected by anthracnose showed sunken, gray to black lesions. No symptoms were observed on the controls. C. brevisporum was successfully reisolated from symptomatic leaves and fruits and was identified by observing morphological and molecular characteristics, which fulfilled Koch’s postulates. In China, hosts of C. brevisporum include peppers (Liu et al. 2016) and pumpkin (Liu et al. 2017). To our knowledge, this is the first report of papaya anthracnose caused by C. brevisporum in China. This finding is helpful to the establishment of effective quarantine regulations, screening of chemical fungicides, and breeding for disease resistance of papaya anthracnose.The author(s) declare no conflict of interest.References:He, F., et al. 2010. Southwest China J. Agric. Sci. 23:752. Google ScholarLiu, F., et al. 2016. Sci. Rep. 6:32761. https://doi.org/10.1038/srep32761 Google ScholarLiu, L., et al. 2017. Plant Dis. 102:1038. https://doi.org/10.1094/PDIS-08-17-1271-PDN Google ScholarNoireung, P., et al. 2012. Cryptogam.: Mycol. 33:347. https://doi.org/10.7872/crym.v33.iss3.2012.347 Crossref, ISI, Google ScholarThe author(s) declare no conflict of interest.Funding: Funding was provided by the project of support plan for modern agricultural talents of the Ministry of Agriculture (grant no. 0316001).DetailsFiguresLiterature CitedRelated Vol. 103, No. 9 September 2019SubscribeISSN:0191-2917e-ISSN:1943-7692 DownloadCaptionLeaf spot caused by Allophoma tropica on lettuce (Gullino et al.). Photo credit: M. L. Gullino. Red grapevine leaves showing symptoms of ‘Candidatus Phytoplasma solani’ (Jamshidi et al.). Photo credit: G. Romanazzi. Metrics Article History Issue Date: 30 Aug 2019Published: 10 Jul 2019First Look: 1 May 2019Accepted: 27 Apr 2019 Pages: 2473-2473 Information© 2019 The American Phytopathological SocietyFundingproject of support plan for modern agricultural talents of the Ministry of AgricultureGrant/Award Number: no. 0316001KeywordspapayaanthracnosephytopathogenidentificationThe author(s) declare no conflict of interest.Cited byBiocontrol of Colletotrichum brevisporum in soybean using a new genistein-producing Paecilomyces strainBiological Control, Vol. 169Melatonin Maintains Fruit Quality and Reduces Anthracnose in Postharvest Papaya via Enhancement of Antioxidants and Inhibition of Pathogen Development20 April 2022 | Antioxidants, Vol. 11, No. 5First Report of Leaf Spot on Kidney Bean Caused by Nigrospora oryzae in ChinaMing-Yan Luo and Yu-Lan Jiang16 February 2022 | Plant Disease, Vol. 106, No. 3Colletotrichum species and complexes: geographic distribution, host range and conservation status29 September 2021 | Fungal Diversity, Vol. 110, No. 1First Report of Anthracnose of Papaya (Carica papaya) Caused by Colletotrichum siamense in ChinaYujie Zhang, Wenxiu Sun, Ping Ning, Tangxun Guo, Suiping Huang, Lihua Tang, Qili Li, and Jianyou Mo22 September 2021 | Plant Disease, Vol. 105, No. 8Diversity of Colletotrichum Species Associated with Anthracnose Disease in Tropical Fruit Crops—A Review30 March 2021 | Agriculture, Vol. 11, No. 4First Report of Colletotrichum brevisporum Causing Soybean Anthracnose in ChinaX.-C. Shi, S.-Y. Wang, X.-C. Duan, X. Gao, X.-Y. Zhu, and P. Laborda25 January 2021 | Plant Disease, Vol. 105, No. 3

多主棒孢（Corynespora cassiicola）是一种全球分布的重要植物病原真菌,寄主范围十分广泛。近年来,该病原菌侵染危害多种热带作物,并在局部地区大面积暴发流行,造成巨大的经济损失。本研究利用核糖体转录间隔区（Internal transcribed spacer, ITS）、翻译延伸因子（translation elongation factor 1 alpha, EF-1α）、β微管蛋白（β-Tubulin,TUB）,对来自橡胶树、木薯、番木瓜和瓜菜等多种热带作物的70株多主棒孢进行种群多样性分析。结果发现,利用最大似然法,在相似系数为0.97时可将供试菌株划分为两大遗传类群:类群Ⅰ为国内和一些国外橡胶树的多主棒孢;类群Ⅱ为其他寄主多主棒孢,遗传类群与寄主来源具有显著的相关性。致病力测定表明,多主棒孢种内致病力分化明显,类群Ⅰ的橡胶树多主棒孢仅能侵染橡胶树,不能侵染其他寄主,具有明显的寄主专化性,且不同地理来源的菌株致病力差异不显著。类群Ⅱ的多主棒孢在不同寄主间可以相互侵染,但菌株在致病力和发病症状上存在一定差异,表现出对其原寄主的高度致病力。多基因序列聚类分析与致病力分化分析结果具有较好的一致性,这为研究我国热带作物多主棒孢的种群结构、主要致病型以及为多主棒孢病害的发生、流行和防治提供了理论依据。

多主棒孢(Corynespora cassiicola)是为害我国主要热带作物的植物病原真菌,其寄主范围广、形态差异显著、症状类型多样,且含有一种寄主专化性毒素Cassiicolin,存在6种毒素类型.本研究利用已公布的Cassiicolin毒素基因(Cas1～Cas6型),构建了含287个菌株的国内橡胶树和部分热带作物多主棒孢Cassiicolin基因条形码数据库,建立了一套特异性强、灵敏度高的分子检测技术,可检测100 pg/μL的目标基因组DNA,系统分析了我国橡胶树、木薯、番木瓜、瓜菜等主要热带作物的919株多主棒孢的毒素类型,发现国内仅存在Cas2和Cas5这2种毒素类型,其中Cas5型的菌株占94.8％,为橡胶树多主棒孢的优势种群和特有毒素类型.而Cas2型是橡胶树和其他作物多主棒孢共有的毒素型.系统发育分析发现,不同毒素类型的多主棒孢菌株与寄主来源密切相关,但与地理来源没有明显的相关性,且Cas5型多主棒孢具有明显的寄主专化性.通过构建多主棒孢Cassiicolin基因条形码数据库,为明确我国主要热带作物多主棒孢病菌的种群结构和优势种群情况,发掘、保存多主棒孢菌种资源以及制定病害的防治策略上具有重要的指导意义.

Anthracnose caused by Colletotrichum is one of the most severe diseases of Hevea brasiliensis. However, research on the diversity and geographical distribution of Colletotrichum remains limited in China. In this study, we investigated the phylogenetic diversity of Colletotrichum isolates associated with symptomatic tissues of H.brasiliensis from four provinces of China (Hainan, Guangdong, Guangxi, and Yunnan). Based on multi-locus phylogenetic analyses and phenotypic characteristics, five species were distinguished, including two known species (C. fructicola, C. siamense), one novel species of C. gloeosporioides species complex (C. ledongense), and two novel species of C. acutatum species complex (C. bannanense and C. australisinense). Of these, C. siamense and C. australisinense have been recognized as major causative agents of anthracnose of H. brasiliensis.