Falconí César E, Visser Richard G F, van Heusden Adriaan W
Agropecuarian Science Faculty, Life Science Department, Army Polytechnic School, Sangolqui, Ecuador.
Wageningen UR Plant Breeding, Wageningen, The Netherlands.
Plant Dis. 2013 Jun;97(6):819-827. doi: 10.1094/PDIS-02-12-0175-RE.
Anthracnose is a serious problem of both Andean lupine and tamarillo in Ecuador. Morphological features, internal transcribed spacer (ITS) sequences, and host specificity were used to characterize Colletotrichum isolates from lupine and tamarillo. Based on phenotypic and molecular characterization, the causal agent of anthracnose on both hosts was Colletotrichum acutatum. All isolates were identified in a C. acutatum-specific polymerase chain reaction assay. Colony diameter, conidia shape, and insensitivity to benomyl also placed isolates from both hosts in the C. acutatum group. However, a detailed analysis of the ITS sequences placed the lupine and tamarillo isolates from the Ecuadorian Andean zone in two clades, with both lupine and tamarillo isolates in each clade. C. acutatum isolates from Andean lupine were distinct from other C. acutatum isolates on lupine around the world. In cross-infection studies, the diameter of lesions produced by isolates from each host was compared on the main stem of two tamarillo and three lupine cultivars. Some isolates produced larger lesions on the host from which they were isolated but others showed similar aggressiveness on their alternate host. Isolates from both hosts were biotrophic on lupine stems, producing little necrosis and abundant sporulation whereas, on tamarillo stems, they produced dark lesions with few conidia. The collection of C. acutatum isolates from lupine and tamarillo provides interesting material for the study quantitative host adaptation.
炭疽病是厄瓜多尔安第斯羽扇豆和番茄树面临的一个严重问题。利用形态特征、内转录间隔区（ITS）序列和寄主特异性对羽扇豆和番茄树上的炭疽菌分离株进行了鉴定。基于表型和分子特征，两种寄主上炭疽病的病原菌均为尖孢炭疽菌。所有分离株均通过尖孢炭疽菌特异性聚合酶链反应检测进行鉴定。菌落直径、分生孢子形状以及对苯菌灵的不敏感性也将两种寄主上的分离株归为尖孢炭疽菌群。然而，对ITS序列的详细分析将来自厄瓜多尔安第斯地区的羽扇豆和番茄树分离株分为两个进化枝，每个进化枝中都有羽扇豆和番茄树的分离株。来自安第斯羽扇豆的尖孢炭疽菌分离株与世界其他地区羽扇豆上的尖孢炭疽菌分离株不同。在交叉感染研究中，比较了来自每种寄主的分离株在两个番茄树品种和三个羽扇豆品种主茎上产生的病斑直径。一些分离株在其分离的寄主上产生的病斑较大，但其他分离株在其替代寄主上表现出相似的侵染力。两种寄主上的分离株在羽扇豆茎上都是活体营养型，几乎不产生坏死且产孢丰富，而在番茄树茎上，它们产生深色病斑，分生孢子很少。从羽扇豆和番茄树上收集的尖孢炭疽菌分离株为研究定量寄主适应性提供了有趣的材料。
