Sesame (Sesamum indicum) is an important oil seed crop of Asia. Yields can be negatively impacted by various factors, including disease, particularly those caused by fungi which create problems in both production and storage. Foliar diseases of sesame such as Alternaria leaf blight may cause significant yield losses, with reductions in plant health and seed quality. The work reported here determined the incidence of Alternaria species infecting sesame seeds grown in the Punjab, Pakistan. A total of 428 Alternaria isolates were obtained from 105 seed samples and grouped into 36 distinct taxonomic groups based on growth pattern and morphological characters. Isolation frequency and relative density of surface sterilized and non-surface sterilized seeds showed that three isolates (A13, A47 and A215) were the most common morphological groups present. These isolates were further identified using sequencing of the Internal Transcribed Spacer (ITS) region of ribosomal DNA (rDNA) and the Alternaria major allergen gene (Alt a 1). Whilst ITS of rDNA did not resolve the isolates into Alternaria species, the Alt a 1 sequences exhibited > 99% homology with Alternaria alternata (KP123850.1) in GenBank accessions. The pathogenicity and virulence of these isolates of Alternaria alternata was confirmed in inoculations of sesame plants resulting in typical symptoms of leaf blight disease. This work confirms the identity of a major source of sesame leaf blight in Pakistan which will aid in formulating effective disease management strategies.

中文翻译：

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与来自巴基斯坦旁遮普邦田地的受感染芝麻种子相关的链格孢属物种的发生率。


芝麻（ Sesamum indicum ）是亚洲重要的油料作物。产量可能会受到多种因素的负面影响，包括疾病，特别是由真菌引起的疾病，这些因素会在生产和储存中造成问题。芝麻叶部病害（例如链格孢叶枯病）可能会导致严重的产量损失，并降低植物健康和种子质量。这里报告的工作确定了感染巴基斯坦旁遮普省种植的芝麻的链格孢属物种的发生率。从 105 个种子样品中获得了总共 428 个链格孢分离株，并根据生长模式和形态特征分为 36 个不同的分类群。表面灭菌和非表面灭菌种子的分离频率和相对密度表明，三个分离株（A13、A47 和 A215）是最常见的形态群。使用核糖体 DNA (rDNA) 的内部转录间隔区 (ITS) 区域和链格孢属主要过敏原基因 ( Alt a 1 ) 的测序进一步鉴定了这些分离株。虽然 rDNA 的 ITS 不能将分离株解析为链格孢属物种，但Alt a 1序列与 GenBank 种质中的链格孢属 ( Alternaria alternata ) (KP123850.1) 表现出 > 99% 的同源性。这些链格孢菌分离株的致病性和毒力在芝麻植物接种中得到证实，导致叶枯病的典型症状。这项工作证实了巴基斯坦芝麻叶枯病的主要来源，这将有助于制定有效的疾病管理策略。