Abstract

QUIROZ OJEDA, Claudia Milena; SALAZAR GONZALEZ, Claudia; AROCA ROMO, Sofia  and  BETANCOURTH GARCIA, Carlos. Molecular Identification of Anastomosis Groups of Rhizoctonia Solani Kühn Causing Potato Black Scab in Nariño (Colombia). Ciencia en Desarrollo [online]. 2025, vol.16, n.1, pp.32-45.  Epub Jan 20, 2025. ISSN 0121-7488.  https://doi.org/10.19053/uptc.01217488.v16.n1.2025.17646.

Rhizoctonia solani Kühn, which causes black scab on potato, has increased its incidence in Nariño, making its management difficult. The lack of knowledge of the anastomosis groups (AG) present in its populations contributes to this situation, since they influence the performance of control strategies. Therefore, the genetic variability of R. solani in Nariño was evaluated by the molecular identification of their AG. A total of 287 isolates obtained of potato were analyzed, 116 of them with PCR and ITS1-ITS4 primers and the entire collection with PCR and specific primers for AG-2-1, AG-3 PT and AG-4. Phylogenetic analysis was done with Maximum Likelihood, bootstrap of 1000 replicates and Kimura 2-parameter model. In the molecular characterization with ITS, 1000 % of the sequences matched with R. solani and AG-3 (46), AG-3 PT (69) and AG-2-1 (1) were identified. Specific primers determined the presence of AG-3 PT in 281 and AG-2-1 in six isolates of the pathogen. R. solani AG-2-1 is reported for the first time in Nariño. Phylogenetic analysis grouped the isolates into seven clades, independently of local origin, demonstrating the existence of intraspecific genetic variability in the populations of R. solani present in Nariño.

Keywords : Solanum tuberosum; Stem canker; genetic variability; PCR; primers.

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