Xia H, Wang X-L, Zhu H-J, Gao B-D
Hunan Provincial University Key Lab of Plant Disease Control and Utilization, Hunan Agricultural University, Changsha 410128.
Plant Dis. 2011 Feb;95(2):219. doi: 10.1094/PDIS-10-10-0727.
A new anthracnose disease on chili pepper (cayenne pepper cv. Hongxiu 2003, fruiting type pepper) was found in Zhijiang County, Hunan, China in 2009. The disease was observed only on the fruits. Lesions were generally elongated, on which dark acervuli were arranged concentrically. Later, cracking of older lesions was observed. With a microscope, fungal conidia were observed to be 15.8 × 4.1 μm, fusiform or oval with one end acute, and single celled with two to seven oil globules. No setae were found on the acervuli. Eight isolates (HNZJ001-HNZJ008) showed no difference in colony feature when cultured on potato dextrose agar. All the isolates showed white growth at the early stages, but colonies turned pink when they produced powdery spores and then finally became red gray. The average colony diameter was 68.5 to 72.3 mm after 7 days with obvious gray black concentric rings because of the development of aerial and substrate mycelia. After a needle-prick inoculation with a suspension of 1 × 10 spores per ml of HNZJ001 on 30 chili pepper fruits with three repeats, the same symptoms were observed and the same fungus was recovered. In bioassays, HNZJ001 caused lesions on both mature and immature fruits, while Glomerella cingulata strain LSQ1 (GenBank Accession No. HQ607386) used as a control did not infect immature fruits. PCR amplification was carried out by utilizing universal rDNA-ITS primer pair ITS4/ITS5. Sequencing of the PCR products of HNZJ001 (GenBank Accession No. GU059863) showed 100% identity to G. acutata (GenBank Accession No. EU008863) and Colletotrichum acutatum (GenBank Accession No. AF207794) after a BLAST search. The pathogen was identified as G. acutata (asexual stage: C. acutatum) on the basis of morphological characters and rDNA-ITS sequence analysis. Worldwide, it has been reported that pepper anthracnose might be caused by up to five species of Glomerella (Colletotrichum): G. cingulata, C. coccodes, C. capsici, C. dematium, and G. acutata (2), among which only the first three were previously reported in China. In recent years, G. acutata was reported on such plants as apple (3) and strawberry (1) in China, but not on pepper. To our knowledge, this is the first report of G. acutata on chili pepper in China. References: (1) X.-J. Ren et al. Acta Phytopathol. Sin. 38:325, 2008. (2) P. P. Than et al. Zhejiang Univ. Sci. B 9:764, 2008. (3) R. Zhang et al. Plant Dis. 92:1474, 2008.
2009年，在中国湖南省芷江县发现了一种辣椒（品种为“洪秀2003”，果型辣椒）上的新炭疽病。该病仅在果实上观察到。病斑通常呈长形，上面有黑色分生孢子盘呈同心环状排列。后来，观察到较老病斑出现开裂。在显微镜下，观察到真菌分生孢子为15.8×4.1μm，梭形或椭圆形，一端尖，单细胞，有2至7个油球。在分生孢子盘上未发现刚毛。8个分离物（HNZJ001 - HNZJ008）在马铃薯葡萄糖琼脂上培养时菌落特征无差异。所有分离物在早期生长为白色，但当产生粉状孢子时菌落变为粉红色，最后变为红灰色。7天后平均菌落直径为68.5至72.3mm，由于气生菌丝和基内菌丝的生长，有明显的灰黑色同心环。用每毫升含1×10个孢子的HNZJ001悬浮液对30个辣椒果实进行针刺接种，重复3次，观察到相同症状并分离到相同真菌。在生物测定中，HNZJ001在成熟和未成熟果实上均引起病斑，而用作对照的围小丛壳菌菌株LSQ1（GenBank登录号HQ607386）不感染未成熟果实。利用通用rDNA - ITS引物对ITS4/ITS5进行PCR扩增。对HNZJ001的PCR产物测序（GenBank登录号GU059863），经BLAST搜索后显示与尖孢小丛壳菌（GenBank登录号EU008863）和尖孢炭疽菌（GenBank登录号AF207794）的同源性为100%。根据形态特征和rDNA - ITS序列分析，该病原菌被鉴定为尖孢小丛壳菌（无性阶段：尖孢炭疽菌）。在世界范围内，据报道辣椒炭疽病可能由多达5种小丛壳菌（炭疽菌属）引起：围小丛壳菌、球炭疽菌、辣椒炭疽菌、黑刺盘孢菌和尖孢小丛壳菌（2），其中前3种以前在中国有报道。近年来，中国报道尖孢小丛壳菌在苹果（3）和草莓（1）等植物上发生，但未报道在辣椒上发生。据我们所知，这是中国首次报道尖孢小丛壳菌引起辣椒炭疽病。参考文献：（1）任学军等，植物病理学报38:325，2008。（2）Than P. P.等，浙江大学学报B9:764，2008。（3）张荣等，植物病害92:1474，2008。
