Molecular characterization of slow-growing orange and Key lime anthracnose strains of Colletotrichum from citrus as C-acutatum
Molecular characterization of slow-growing orange and Key lime anthracnose strains of Colletotrichum from citrus as C-acutatum
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DOI：
10.1094/phyto-86-523
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发表时间：
1996-05-01
期刊：
影响因子：
3.2
通讯作者：
Timmer, LW
中科院分区：
文献类型：
--
作者：
Brown, AE;Sreenivasaprasad, S;Timmer, LW
炭疽病在柑橘上有三种形式：快速生长的灰色（FGG）形式，一种常见的腐生植物和采后病原体，在形态上与其他两种不同；慢生橙（SGO）形态是开花后果实掉落的诱因；关键石灰炭疽病（KLA）形式，石灰炭疽病的原因。致病性试验证实，SGO分离株仅感染甜橙花，KLA分离株同时感染甜橙花和酸橙叶，FGG分离株不感染这两种寄主组织。用C. acutatum特异性引物CaInt2和内部转录间隔物（ITS）4引物（来自核糖体DNA [rDNA]的保守序列）进行聚合酶链反应（PCR），从SGO和KLA分离株中扩增出490 bp的片段，但从FGG分离株中扩增不到。用C， gloeosporioides特异性引物CgInt和ITS4引物进行PCR扩增，仅从FGG分离物中扩增出450 bp的片段。4个SGO和4个KLA分离株的rDNA ITS1核苷酸序列表明，它们与acutatum参考分离株具有完全同源性或i碱基差异，而与gloeosporioides参考分离株的同源性仅为80% ~ 81%。FGG分离物的ITS1序列与gloeosporioides参考分离物的同源性为97%，与acutatum参考分离物的同源性仅为80%。这些数据证实了SGO和KLA分离株属于C. actuatum， FGG分离株属于C. gloeosporioides。rDNA和线粒体DNA限制性内切片段聚类分析将SGO和KLA分离物划分为两个可识别的类群，遗传相似性为87%。这两个群体彼此之间的亲缘关系比所使用的任何参考菌株(
Three forms of Colletotrichum are recognized on citrus: the fast-growing gray (FGG) form, a common saprophyte and postharvest pathogen that is morphologically distinct from the other two; the slow-growing orange (SGO) form, the causal agent of postbloom fruit drop; and the Key lime anthracnose (KLA) form, the cause of lime anthracnose. Pathogenicity tests confirmed that the SGO isolates infected sweet orange flowers only, the KLA isolates infected both sweet orange flowers and Key lime foliage, and the FGG isolates did not infect either of these host tissues. Polymerase chain reaction (PCR) with the C. acutatum-specific primer CaInt2 and the internal transcribed spacer (ITS)4 primer (from a conserved sequence of ribosomal DNA [rDNA]) amplified a 490-bp fragment from the SGO and KLA isolates but not from the FGG isolates. PCR with the C, gloeosporioides-specific primer CgInt and the ITS4 primer amplified a 450-bp fragment only from the FGG isolates. The nucleotide sequence of the rDNA ITS1 of four SGO and four KLA isolates indicated either complete homology or a I-base difference from a C. acutatum reference isolate but only 80 to 81% homology to a C. gloeosporioides reference isolate. The ITS1 sequence of the FGG isolates had 97% homology to the C. gloeosporioides reference isolate but only 80% homology to the C. acutatum reference isolate. These data confirmed the classification of the SGO and KLA isolates as C. acutatum and the FGG isolates as C. gloeosporioides. Cluster analysis of rDNA and mitochondrial DNA restriction fragments divided the SGO and KLA isolates into two recognizable groups with genetic similarity of 87%. These two groups were more closely related to each other than to any of the reference isolates used (