湖南芷江辣椒上一种新炭疽病的病原鉴定

 2009 年8 月湖南省芷江县线果型辣椒品种红秀2003 未成熟果实上发生了一种新炭疽病。典型病斑长椭圆状,其中央呈成片黄褐色粉末,外围粉红色小点呈同心圆排列,边缘水渍状。8个分离菌株（HNZJ001 HNZJ008）培养时菌落初呈白色,渐变为浅红色,后期加深, 具明显灰黑色同心轮纹。分生孢子盘无刚毛, 分生孢子单胞，大小为15. 8 μm × 4. 1 μm,含2～7 个油球,一端稍尖。分离菌株HNZJ001 针刺接种,在离体的成熟果和未成熟果上均产生病斑,而作为对照的胶孢炭疽菌Collectotrichum gloeosporioides菌株LSQ1 不能侵染未成熟果。核糖体RNA 基因内转录间隔区(ITS)的PCR 产物经〖JP2〗测序后做BLAST 分析,结果表明该菌与尖孢炭疽菌C. acutatum(有性阶段为尖孢小丛壳Glomerella acutata)的ITS 序列100% 相同,系统进化分析显示置信度高达100%,据此确定该病原为尖孢炭疽菌。这是国内辣椒上尖孢炭疽菌的首次报道。

Pathogen identification of a new anthracnose of pepper in Zhijiang,Hunan

A new anthracnose disease was found on immature fruits of chili pepper(Cayenne pepper cv.Hongxiu 2003,line fruited) in Zhijiang county,Hunan,in August of 2009.Typical lesion was long oval in shape with tawny powder at the center,concentric pink dot periphery and outer water soaked zone.All 8 isolates(HNZJ001-HNZJ008) showed the colonies white at the early stage,then pink,finally dark with obvious grey black concentric rings.No seta was observed on acervuli.Conidia were single-celled,15.8 μm×4.1 μm in size,with a subacute end and 2-7 oil droplets in each cell.After needle prick inoculation with spore suspension,HNZJ001 caused lesions on both mature and immature pepper fruits while the control Collectotrichum gloeosporioides strain LSQ1 did not infect immature ones.PCR product was sequenced.After BLAST analysis,rDNA ITS(internal transcribed spacer) of HNZJ001 revealed 100% nucleotide identity to that of C.acutatum(sexual stage Glomerella acutata).Phylogenetic analysis showed a high bootstrap value of 100%.It comes into conclusion that the pathogen causing anthracnose of immature pepper in Zhijiang be identified as C.acutatum.This is the first report of C.acutatum on chili pepper in China.