APS Homepage

Poster: Molecular & Cellular Plant-Microbe Interactions: MPMI


Phytopathogenic interaction between Herbaspirillum rubrisubalbicas and different genotypes of Sorghum
T. TULESKI (1), T. Tuleski (1), C. Espinoza (2), F. Plucani do Amaral (2), T. Pereira (2), R. Monteiro (4), E. Maltempi de Souza (4), F. Pedrosa (4), G. Stacey (2) (1) University of Missouri, U.S.A.; (2) University of Missouri, U.S.A.; (3) University of M

Herbaspirillum rubrisubalbicans is a nitrogen fixing and plant growth promoting bacterium found in association with important grasses, such as maize and wheat. In contrast, this bacterium is a pathogen on some genotypes of Sorghum bicolor, being responsible for red stripe disease. The pathogen infects sorghum leaves leading to tissue necrosis, a reduction in photosynthesis and impaired leaf development. Twenty five genotypes of sorghum were inoculated with H. rubrisubalbicans with the great majority showing symptoms after 7 days. Bacteria were recovered from portions of the leaf increasingly distal from the site of inoculation. The results showed the spread of both bacteria and symptoms along the expanding leaf. Plants have the ability to mount a defense response to invading pathogens due to recognition of conserved motifs, termed microbe-associated molecular patterns (MAMPs). We tested the ability of MAMP-triggered immunity to protect sorghum plants from H. rubrisubalbicans infection. Sorghum leaves were pre-treated with chitin and flg22 (a conserved 22 amino acid peptide derived from bacterial flagellin) and then challenged with the pathogen. Evaluation of disease symptoms 5 days after inoculation showed strong plant protection in those leaves pretreated with chitin and flg22. The data suggest that H. rubrisubalbicans will be a useful pathogen in which to study the innate immunity response of sorghum, an important grain, forage and bioenergy crop.