Molecular diagnosis of red rot of sugarcane in Pakistan and in vitro control of isolated pathogen using rhizobacteria

Abstract

Sugarcane (Saccharum officinarum L.) is a key cash crop, and its production is influenced by a variety of phy-topathogens in different parts of the world. During consecutive field surveys, sugarcane stalks with red rot symptoms were observed in three provinces of Pakistan (Punjab, Sindh, and Khyber Pakhtunkhwa). Cane samples with visible symptoms were plated on potato dextrose agar (PDA) media. Morphological and microscopic observations identified this pathogen as Colletotrichum falcatum. Comparative molecular study of amplified sequences of β-tubulin (Bt) and actin (ACT) genes showed 100% similarity and ITS sequence showed 99% similarity with C. falcatum. For in vitro control of red rot, eight bacterial strains from the rhizosphere of sugarcane were isolated. These strains showed variable growth inhibition of C. falcatum in dual culture method. Among all tested strains, Bacillus amyloliquefaciens and B. altitudinis exhibited best antifungal activities. Based on these results, tested bacterial strains (B. amyloliquefaciens and B. altitu-dinis) can be recommended as effective biocontrol agents to manage red rot disease of sugarcane.