Phosphate-Mobilizing Rhizobacteria As Biocontrol Agents Against Wheat Diseases Caused by Bipolaris Sorokiniana

Аннотация

Bipolaris sorokiniana are a destructive hemibiotrophic pathogen causing root and crown rot, leaf spot and black mold of cereal crops, which significantly reduces grain yield and quality worldwide. This study investigated the antagonistic activity of 20 strains of phosphate-mobilizing wheat rhizobacteria from the genera Rahnella, Enterobacter, Bacillus, Paenibasillus and Pseudomonas against wheat diseases caused by B. sorokiniana. It was found that out of 20 strains of rhizobacteria 5 strains (Enterobacter clocae 7, Bacillus cereus 23, Pseudomonas kilonensis 24, P. kilonensis 26, P. kilonensis 30) 100% inhibited the growth of phytopathogen B. sorokiniana. Keywords: Bipolaris sorokiniana, phosphate-mobilizing rhizobacteria, wheat, antagonistic activity, biological control. is a globally distributed pathogen of common root rot, Introduction: Wheat (Triticum aestivum) is one of the leaf spot, seedling blight, bunt blight and black spot on most widely grown crops in the world. In 2018, its wheat and barley. This fungus is one of the most serious production exceeded 734 million tons on an area of 214 leaf spot diseases in both crops in warm growing million ha [1]. Wheat production is constrained by regions and causes significant yield losses. High biotic stresses, chief among which are yield-limiting temperature and high relative humidity favor the diseases worldwide. Out of more than 200 wheat spread of the disease, especially in intensive irrigated diseases, about 50 cause significant economic losses [2- wheat and rice production systems in South Asia. B. 7]. Diseases cause approximately 20% yield loss sorokiniana can develop endophytically, epiphytically, annually. Rust, spot blight, root rot, parsha, septoriosis, persist for long periods of time in soil and on plant powdery mildew, fusarium and other viral, nematode debris. The chemical mechanisms of such good and bacterial diseases are considered the most adaptability of this fungus to different environments damaging [8-11]. are still poorly understood [14-19]. Wheat has been a key food crop in the world for Among the various diseases caused by B. sorokiniana, thousands of years. However, its yield is often reduced leaf spots of wheat and barley are the most important, by various biotic stresses [12]. Among the most especially under the high temperature and humidity dangerous pathogens that affect the leaves, stems and conditions typical for some agricultural regions [20]. grain of wheat is Bipolaris sorokiniana. This fungus has This phytopathogen poses a serious threat to more been repeatedly associated with the occurrence of than a thousand plant species, including the major spotting on wheat, leading to yield losses ranging from cereal crops wheat, barley, rye, maize, rice, and millet 16 to 43%, especially in regions with a warm and humid [21]. Moreover, in 2021, B. sorokiniana was reported climate [13]. for the first time on lentil cultivar Syria 229, expanding One of the important soil diseases of wheat is common the potential host range of this pathogen [22]. root rot, caused by Bipolaris sorokiniana (Sacc. in In recent years, attention to the search for biocontrol Sorok.) Shoem. The micromycete Bipolaris sorokiniana American Journal Of Agriculture And Horticulture Innovations 33 https://theusajournals.com/index.php/ajahi American Journal Of Agriculture And Horticulture Innovations (ISSN: 2771-2559) agents has increased, and it is important to identify rhizosphere of wheat and screened them for their antagonistic strains that can complement cultural and phosphate-mobilizing capabilities, identifying the most chemical defense methods under field conditions. efficient strains based on their ability to solubilize inorganic phosphates [25]. In the present study, we Therefore, the aim of this study was to investigate the further evaluated the biocontrol potential of these antagonistic activity of phosphate-mobilizing phosphate-mobilizing rhizobacteria by assessing their rhizosphere bacteria of wheat against the antagonistic activity against Bipolaris sorokiniana, a phytopathogen B. sorokiniana. major fungal pathogen responsible for spot blotch METHODS disease in wheat. The objects of research were 20 local strains of A total of 20 phosphate-mobilizing rhizobacterial phosphate-mobilizing rhizobacteria of wheat. strains, taxonomically affiliated with the genera Rhizobacterial strains were cultured at t=28±2ºС for 5 Rahnella, Enterobacter, Bacillus, Paenibacillus, and days under aerobic conditions on peptone liquid Pseudomonas, were selected for antagonism assays nutrient medium with glucose. The fungus was against B. sorokiniana. The antagonistic activity of cultivated in liquid Czapeka nutrient medium (20 g phosphate-mobilizing rhizobacteria against the glucose, 2 g NaNO3, 1 g KH2PO4, 0.5 g MgSO4・7H2O, phytopathogenic fungus Bipolaris sorokiniana was 0.5 g KCl, water up to 1 l, pH 6) [23]. Phytopathogenic evaluated in vitro using well method on Czapeka fungi