Rice Pathology Laboratory, All India Coordinated Rice Improvement Programme, University of Agricultural Sciences, Raichur, India.
Department of Plant Pathology, University of Agricultural Sciences, Bangalore, India.
J Appl Microbiol. 2021 Nov;131(5):2372-2386. doi: 10.1111/jam.15087. Epub 2021 Apr 10.
To characterize the geo-distinct isolates of Ustilaginoidea virens for morpho-molecular and mating-type locus diversity.
Sixty-one isolates of U. virens collected from Southern India exhibited significant diversity in mycelial width (3·45-5·50 µm), colony colour (yellow, pale yellow, and white), and growth pattern (thick leather mat, raised-fluffy, flat-fluffy, and raised). Field-borne chlamydospores of each isolate were significantly smaller in size (3·34-5·26 µm ) compared to those formed on culture media (18·6-100·89 µm ). The phylogenetic study based on internal transcribed sequences revealed two clusters; however, most isolates (n = 54) were grouped in cluster-I, indicating common ancestral origin. We also identified 42 haplotypes; among them, Hap_3 has the highest number of isolates (n = 19). Mating-type locus (MAT1) analysis revealed all sixty-one isolates as heterothallic, wherein 37 and 24 isolates belonging to MAT1-1-1 and MAT1-2-1 heterothallic mating types, respectively. The microsynteny analysis of MAT1 loci of one of the Indian strain (Uv-Gvt) along with Uv-8b (China) strain revealed synteny conservation at MAT1 locus, which is flanked by conserved genes SLA2 and a hypothetical protein in the upstream and APN2, COX12 and APC5 in the downstream of the locus.
Morpho-molecular study revealed the significant diversity among geo-distinct isolates, and MAT1 loci analysis indicated the distribution of heterothallic mating types in south Indian paddy fields. And also, complete synteny conservation between Indian and Chinese strain was observed at the MAT1 locus.
This is the first report describing the sexuality of Indian strains of the U. virens, which would help better understand the genetic diversity of the U. virens prevailing in Southern India and aid in developing resistant rice cultivars against this pathogen population.
对绿核菌的地理分离株进行形态分子和交配型基因座多样性特征描述。
从印度南部采集的 61 个绿核菌分离株在菌丝宽度（3.45-5.50μm）、菌落颜色（黄色、浅黄色和白色）和生长模式（厚革质垫状、凸起状蓬松、扁平状蓬松和凸起状）方面表现出显著的多样性。与在培养基上形成的相比，每个分离株的田间产生的厚垣孢子明显更小（3.34-5.26μm）。基于内部转录序列的系统发育研究显示有两个聚类；然而，大多数分离株（n=54）被归类为聚类-I，表明它们具有共同的祖先起源。我们还鉴定了 42 个单倍型；其中，Hap_3 有最多的分离株（n=19）。交配型基因座（MAT1）分析显示，所有 61 个分离株均为异宗配合，其中 37 个和 24 个分离株分别属于 MAT1-1-1 和 MAT1-2-1 异宗配合交配型。对印度菌株（Uv-Gvt）和中国菌株 Uv-8b 的 MAT1 基因座的微同线性分析显示，MAT1 基因座侧翼的保守基因 SLA2 和一个假设蛋白在基因座的上游以及 APN2、COX12 和 APC5 在基因座的下游均存在保守性。
形态分子研究揭示了地理分离株之间的显著多样性，而 MAT1 基因座分析表明，在印度南部稻田中存在异宗配合交配型的分布。并且，在 MAT1 基因座上观察到印度和中国菌株之间的完全同线性保守性。
这是首次报道印度绿核菌菌株的有性生殖，这将有助于更好地了解在印度南部流行的绿核菌的遗传多样性，并有助于开发针对该病原菌种群的抗性水稻品种。
