First report of Pectobacterium versatile causing aerial stem rot on potato crops in Mexico

Area of Science:

• Plant Pathology
• Bacteriology
• Molecular Biology

Background:

• Potato (Solanum tuberosum L.) is a vital crop globally.
• Aerial stem rot significantly impacts potato yield and quality.
• Emerging bacterial pathogens pose a threat to agricultural productivity.

Purpose of the Study:

• To identify the causal agent of potato aerial stem rot observed in Sinaloa, Mexico.
• To confirm the pathogenicity of the isolated bacteria.
• To provide the first report of Pectobacterium versatile causing potato aerial stem rot in Mexico.

Main Methods:

• Isolation and characterization of bacteria from symptomatic potato stems.
• Biochemical and morphological analyses of bacterial isolates.
• Molecular identification using recA and multi-locus sequence analysis (MLSA) of dnaX, dnaJ, and gyrB genes.
• Pathogenicity tests on potato plants (cv. Fianna) and re-isolation of the pathogen.

Main Results:

• Five Pectobacterium spp. isolates were obtained from diseased potato stems.
• Molecular analyses confirmed two isolates as Pectobacterium versatile, with 100% identity to the type strain 14A.
• Inoculation studies demonstrated that P. versatile caused aerial stem rot symptoms, fulfilling Koch's postulates.
• Re-isolation and PCR confirmed the identity of the pathogen from infected plants.

Conclusions:

• Pectobacterium versatile is identified as the causal agent of potato aerial stem rot in northern Sinaloa, Mexico.
• This finding underscores the increasing importance of the Pectobacterium genus as a pathogen in Mexican potato cultivation.
• Further research is needed to assess the diversity of Pectobacterium species in Mexican potato-producing regions.