Cultural Characteristics and Molecular Confirmation of Ustilaginoidea virens the Incitant of False Smut of Rice

Aims: Ustilaginoidea virens, which causes false smut of rice (synonyms: green smut or pseudo smut), is an emerging grain disease around the world. The main aim of the study is to find out suitable culturable medium, carbon sources and pH for the growth of false smut pathogen and molecular confirmation of U. virens isolates.

Place and Duration of Study: The in vitro studies were conducted in the Department of Plant Pathology, Tamil Nadu Agricultural University, Coimbatore, between December 2020 to April 2021.

Methodology: To study the growth pattern of U.virens, five different carbon sources and mediums were used. Standardization of pH was done using a PSA medium amended with different pH levels. DNA extraction of all 13 isolates were done using the CTAB method. The phylogenetic tree was constructed using MEGA 12 software.

Results: It is a slow-growing pathogen and grew well in the potato sucrose agar medium with a mycelial growth of about (54.00 mm) after 30 days and sucrose was found to be a good carbon source. The pH of 5 was found to be optimum. PCR reaction was carried out to further validate 13 isolates using three sets of primer pairs ITS 1/ITS 4, US1-5/US3-3, and US 2-5/US 4-3 with amplified products of 560 bp, 380 bp and 260 bp. Accession numbers were obtained for all the isolates.