Abstract

Rhynchosporium commune, the cause of barley scald, is an important disease of barley in Canada. Multiple studies have indicated that cryptic sexual reproduction may occur between opposite mating types (MAT1-1 and MAT1-2). The occurrence of R. commune mating types in Canada has not been determined previously. Infected leaves from barley cultivars in seven commercial fields and three breeding nurseries in central Alberta were collected and subjected to multiplex PCR to assess the presence of scald mating types within the lesions. Mating types were determined in 410 scald lesions from 288 leaves. Over 10% of lesions contained both mating types, and 44% of leaves with more than one lesion analyzed were colonized by both mating types. The mating types significantly deviated from the 1:1 ratio that would have been expected with frequent sexual reproduction. MAT1-2 was more common in six of the ten locations and for the region as a whole. The presence of both mating types, often in close proximity to each other, suggests that the cryptic sexual stage could be present in Alberta if it does occur. The skewed mating type ratio does suggest, however, that asexual reproduction is predominant within the pathogen population.

摘要

引起大麦烫伤的Rhynchosporium community是加拿大大麦的重要病害。多项研究表明，在相反的交配类型（MAT1-1和MAT1-2）之间可能会发生神秘的有性生殖。R.公社的发生加拿大的交配类型以前尚未确定。收集了来自艾伯塔省中部七个商业田地和三个育种苗圃的大麦品种的受感染叶子，并进行多重 PCR 以评估病灶内是否存在烫伤交配类型。在 288 片叶子的 410 个烫伤病灶中确定了交配类型。超过 10% 的病斑包含两种交配类型，并且 44% 的分析超过一个病灶的叶子被两种交配类型定植。交配类型明显偏离了频繁有性繁殖所预期的 1:1 比例。MAT1-2在十个地点中的六个地点以及整个地区更为常见。两种交配类型的存在，通常彼此非常接近，表明如果确实发生，阿尔伯塔可能存在隐秘的性阶段。然而，倾斜的交配类型比例确实表明，无性繁殖在病原体种群中占主导地位。