Morpho‐molecular and mating‐type locus diversity ofUstilaginoidea virens: an incitant of false smut of rice from Southern parts of India

Abstract

Aims: To characterize the geo-distinct isolates of Ustilaginoidea virens for morpho-molecular and mating-type locus diversity. Methods and Results: Sixty-one isolates of U. virens collected from Southern India exhibited significant diversity in mycelial width (3Á45-5Á50 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 (3Á34-5Á26 µm 2 ) compared to those formed on culture media (18Á6-100Á89 µm 2 ). 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. Conclusions: 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. Significance and Impact of the Study: 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.

Cultural, Molecular and Genetic Variability of Ustilaginoidea virens Causing Rice False Smut Disease

“…Whereas, MAT1-2-1 primer was yielded a product of 220 bp and contain 12 isolates. Our findings were similar with [21,25], who studied mating type of analysis using the MAT1-1-1 and MAT1-2-1 locus primers. The nucleotide divergence analysis results revealed that numbers of polymorphic sites (s) were found 7, mutations (Eta) found 10, nucleotide diversity (k) was found 0.76515, tajimas test value was -2.13885.…”

“…The experiment results were accordance with [25], who studied 61 isolates and observed nucleotide diversity (k) of 0.9163.…”

“…Among them, hap_1 was the major group and contained 24 isolates. Similar results were observed by [25], who studied 61 isolates and observed 42 haplotypes. Similarly, clear nucleotide variations were observed between Indian isolates and China as well as Japanese isolates.…”

“…Similar results were observed, [5], who studed 9 isolates and confirmed as U. virens using the specific primers of US1-5/US3-3 and US2-5/US4-3. In phylogenetic tree analysis results reveled that, cluster (I) contain 5 isolates wereas cluster (II) contain 28 isloates includes china and japan isloates.Similar results were observed by [25], who studied 71 U. virens isolates for phylogenetic analysis among them, 54 isolates was grouped into clusters (I) and 7 isolates were groued in cluster (II). The MAT1-1-1 primer was amplified a product of 250 bp and contain 18 isolates.…”

Multigene phylogeny and haplotype analysis reveals predominance of oomycetous fungus, Phytophthora meadii (McRae) associated with fruit rot disease of arecanut in India

“…The higher haplotype variation between the isolates showed that the haplotypes were closely related, and they differed in smaller nucleotide variations. These results were confirmed by a high haplotype diversity of 0.9163 and a low nucleotide variation among 45 haplotypes identified in 71 isolates of Ustilaginoidea virens infecting rice ( Sharanabasav et al, 2021 ). A high degree of sequence divergence between isolates of Phytophthora cinnamomi has been reported in a total of 45 haplotypes ( Martin and Coffey, 2012 ).…”