RUDN Biologist Describes the Genetic Diversity of 57 Strains of a Dangerous Phytopathogen

A RUDN biologist for the first time described the genetic and other features of more than 50 strains of a bacterium that infects many crops around the world. The results will be important for plant breeding for resistance to phytopathogens . Results published in Brazilian Journal of Biology

Phytopathogenic Pseudomonas syringae infect crop plants across the World. Ice-nucleation in plant tissues due to a special protein and toxin formation are known mechanisms of virulence for this pathogen. Pathological variants of Pseudomonas affect a number of various important plant species. However, despite the long history of studying this pathogen, an information about its diversity in Russia is still limited. RUDN biologist for the first time described the genetic diversity of local Pseudomonas syringae population.

“Bacteria of this species cause plant diseases around the world. The taxonomic structure of this phytopathogen is quite complex and is constantly being revised as new molecular and biochemical diagnostic methods become available. We described for the first time the genetic and phenotypic diversity of 57 strains of Pseudomonas syringae isolated in Russia,” said Alexander Ignatov, Doctor of Science in Biology, Professor of the Agro-Biotechnological Department of the RUDN University.

Biologists took samples of bacteria that infected sunflowers, soybeans, cereals and other plants collected in Russia from 1950 to 2019. Genetic diversity was assessed using the multilocus sequence typing (MLST). Its essence lies in comparing the DNA sequence of several small fragments of vital genes in different bacteria. Previously, RUDN biologists tested the pathogenicity of strains on seedlings of plants most susceptible to disease. In addition, the researchers assessed pathogen susceptibility to 10 antibiotics with different mechanisms of action.

Most of the strains turned out to be “generalist pathogens” without a certain specialization. From a genetic point of view, the strains were found to be highly homogeneous. They were divided into several groups according to the genetic relationship. The pathogen inhibits the growth of the primary root and stem of plants, causes necrotic damage to the host plants. The bacteria turned out to be sensitive to some antibiotics, and without pronounced differences between different pathological variants. However, RUDN University biologists found that over the years, more strains became resistant to antibiotics.

“MLST data is useful in identifying bacterial species. Understanding the species composition is necessary for solving many practical problems – combating bacterial diseases, breeding plants for resistance, and so on,” said Alexander Ignatov, Doctor of Science in Biology, Professor of the Agro-Biotechnological Department of the RUDN University