Biodiversity of Pyricularia oryzae Cav. in rice-growing regions of the south of Russia using PCR method

Abstract

The purpose of this research by the way of investigating the molecular genetic structure of a highly variable fungal phytopathogen Pyricularia oryzae Cav., to determine effective genes for the development of a strategy for immunogenetic protection against rice blast in conditions of epiphytotic development of the disease in the south of Russia, which would combine high efficacy with both environmental friendliness and resource and energy saving, to ensure country's food security. The knowledge of local pathotype diversity of Pyricularia oryzae Cav. and the (a)virulence genes in rice-growing regions of Russia may allow the prediction of new races and its interaction in local agro-ecology. The identification of virulence gene may become an indispensable theoretical basis for the development of genetic sources with long-lasting resistance to rice blast. Based on molecular and genetic approaches, the genetic structure and biodiversity of the phytopathogenic fungus Pyricularia oryzae Cav. in the south of Russia were considered. The monitoring was studied and it isolated 57 strains of the pathogen from the damaged herbal material collected from the fields in eight agro-ecological rice-growing regions of the Krasnodar Region (Russian Federation): Krasnoarmeysky, Kalininsky, Krymsky, Abinsky, Temryuksky, Seversky, Slavyansky districts, Krasnodar, Rostov Region (Russian Federation)-Proletarsky district and the Republic of Adygea (Russian Federation). A multiplex PCR technique was applied on the basis of fragment analysis to identify the virulent fungal isolates. 33 fungal genotypes with unique genetic profiles were identified among the studied races of Pyricularia oryzae Cav. Their DNA profiles were created. The studied isolates of the pathogen of rice blast were classified using morphological and microbiology cultural features. Based on the phytopathological test using differentiation rice varieties, the quantitative and qualitative composition of (a)virulence genes in fungal races was established. Effective genes for pathogen resistance, which are recommended for breeding programs for the development of rice varieties resistant to rice blast, were identified in the south of Russia.

Retrospective research of rice blast development in Krasnodar region

“…A comparative analysis of data on the number of excesses and damage to rice crops by blast is presented in Figure 1. The diagram shows that high values of crop damage occur in years, in the pre-growing season of which a high number of excesses is noted (8)(9)(10)(11)(12). At the same time, years with a low number of excesses in the pre-growing season show a low level of crop damage.…”

“…Pathogen occurs throughout the entire growing season of rice plants and is directly dependent on agroclimatic conditions. In addition, after the end of the growing season (harvesting), spores (conidia) of blast can be retained on crop residues, soil and plants developing in close proximity to areas where rice is cultivated [10,11]. Under certain conditions, individual conidia can give rise to a new generation and create an increased infectious background by the beginning of the next growing season.…”

Development of a methodology for predicting the development of rice blast in southern Russia to improve the environmental friendliness and food security of the country

“…The degree of influence of external factors on the development of microorganisms is determined by the models for predicting the dynamics of the development of the pathogen established in guidelines by V.I. Terekhov [4] and scientific works of V.G. Anikeev [1].…”

“…Rice blast (causative agent -imperfect fungus Pyiricularia Oryzae Cav.) is one of the most dangerous fungal diseases in the cultivation of Oryza sativa L. around the world [4,5]. A pathogen is a microorganism, which, by its nature, is able to adapt quickly enough to environmental conditions, both from the climate side and as a result of agrotechnological measures [3,7].…”

“…A pathogen is a microorganism, which, by its nature, is able to adapt quickly enough to environmental conditions, both from the climate side and as a result of agrotechnological measures [3,7]. Therefore, in order to prevent the development of blast in a timely manner, it is very important today to monitor the disease and the development of the disease under the prevailing macroclimate, modern cultivation technologies and a large variety of rice crop, as well as to identify patterns that reflect the effect on the dynamics of the disease of cultivated plants [8,10].…”