Influence of Bacillus amyloliquefaciens subsp. plantarum IMV B-7404 strain exometabolites on phenylalanine ammonia-lyase activity in winter wheat seedlings

Abstract

Influence of Bacillus amyloliquefaciens subsp. plantarum IMV B-7404 strain exometabolites on phenylalanine ammonia-lyase (PaL, eC 4.3.1.24) A erobic spore-forming bacteria of Bacillus genus are considered as perspective agents of biological control, since they are antagonists to numerous phytopathogenic fungi and bacteria owing to synthesis of a broad range of secondary metabolites with expressed bactericidal and fungicidal properties [1]. One should note not only antibiotic substances among Bacillus genus bacteria exometabolites but also compounds characterized by phytostimulating and immunomodulating activity. The latter, in its turn, determines the expediency of using the Bacillus strains when creating efficient biological preparations of broad-range effect for plant growing needs [2].Bacillus amyloliquefaciens subsp. plantarum IMB B-7404 strain with antifungal activity as to phytopathogens Fusarium graminearum and Bipolaris sorokiniana [3] was selected by the results of screening conducted by the authors. The nature of IMB B-7404 strain exometabolites, which determines its phytostimulating and antagonistic activity [4,5], was studied. Using MALDI-TOF mass-spectrometry and molecular genetic methods of analysis, it was also established that lipopeptide antibiotic exometabolites of the studied strain belonged to the family of fengicins [6].Phytoimmunity development is a complex biochemical process induced by stress factors of biotic and abiotic nature. It is known that activation of phenol metabolism and, in particular, an increase of activity of the basic anti-stress enzymes -phenylalanine ammonia-lyase (PAL, EC 4.3.1.24) and peroxidase is one of defense responses of plants to the effect of stressors. The enzyme PAL is one of recognized biochemical markers of the induced plant resistance both to diseases caused by phytopathogens and to the effect of various stressor factors of biotic and abiotic nature. PAL performs deamination of phenylalanine with formation of trans-cinnamic acid and ammonia, takes part in synthesis of salicylic acid precursors, phytoalexins, lignin monomers, which strengthen mechanical and chemical barriers of plant cells and thus prevent their infection by phytopathogenic fungi [7,8]. PAL activity can change depending on the phase of plant development, its genotype and external conditions [9]. The work [10], where the enzyme activity was depressed by specific inhibitors, evidences for the important role of PAL in phytoimmunity induction. Under treatment by these inhibitors, the pathogenic lesion increased even in genetically resistant plants, as a result of the cessation of forming phenols and lignin precursors.

The Effect of Bacillus amyloliquefaciens subsp. plantarum IMV B-7524 Strain Exometabolites on the Induction of Defense Reactions in Winter Wheat Plants

“…plantarum IMV B-7524, and then its infection with phy topathogenic micromycetes B. sorokiniana, a significant decrease in the dam aged by dark brown spot surface area of leaves was observed. That agrees with results obtained previously on another strain of bacilli [18]. Since under the terms of the experiment treatment with exometabolites of bacilli and conidia of phytopathogen were separated in space and time, such a result was likely to be achieved not only by direct fungitoxic effect of microbial antibiotics (which is characterized, in particular, for fengycins present among exometabolites of strain), but, also, by its own capacities of plant self-defense.…”

“…Infection of winter wheat plants was performed as described in [18]. For this purpose, the seeds were germinated in sterile sand for 12-14 days, feeding twice with Knopp solution 2 times diluted with water.…”

“…Effect of exometabolites of the studied strain on the PAL activity in wheat plants was investigated as described in [18]. For this purpose, the winter wheat was grown and treated with solutions, as described above.…”

The Impact of Biopreparations and Phytopathogenic Bacteria of the Pseudomonas Genus on L-Phenylalanine Ammonia-Lyase Activity in Soybean and Lupine Plants

“…Therefore, the search for alternative measures aimed at minimizing their harmful effects on the environment is becoming increasingly popular. Induced plant resistance is one of the promising non-chemical strategies for effective preventing the spread of disease [2].…”

“…SAR is systemically induced after pathogen invasion or the use of certain chemicals, in particular salicylic acid [6]. Some rhizobacteria can stimulate and increase plant resistance against pathogens [2,7]. Induction of these pathways at the same time can significantly improve plant protection against biotic agents in general, and phytopathogens in particular [3].…”