Novel Genetic Dysregulations and Oxidative Damage in Fusarium graminearum Induced by Plant Defense Eliciting Psychrophilic Bacillus atrophaeus TS1

Abstract

This study elaborates inter-kingdom signaling mechanisms, presenting a sustainable and eco-friendly approach to combat biotic as well as abiotic stress in wheat. Fusarium graminearum is a devastating pathogen causing head and seedling blight in wheat, leading to huge yield and economic losses. Psychrophilic Bacillus atrophaeus strain TS1 was found as a potential biocontrol agent for suppression of F. graminearum under low temperature by carrying out extensive biochemical and molecular studies in comparison with a temperate biocontrol model strain Bacillus amyloliquefaciens FZB42 at 15 and 25 °C. TS1 was able to produce hydrolytic extracellular enzymes as well as antimicrobial lipopeptides, i.e., surfactin, bacillomycin, and fengycin, efficiently at low temperatures. The Bacillus strain-induced oxidative cellular damage, ultrastructural deformities, and novel genetic dysregulations in the fungal pathogen as the bacterial treatment at low temperature were able to downregulate the expression of newly predicted novel fungal genes potentially belonging to necrosis inducing protein families (fgHCE and fgNPP1). The wheat pot experiments conducted at 15 and 25 °C revealed the potential of TS1 to elicit sudden induction of plant defense, namely, H2O2 and callose enhanced activity of plant defense-related enzymes and induced over-expression of defense-related genes which accumulatively lead to the suppression of F. graminearum and decreased diseased leaf area.

Bacillus thuringiensisCHGP12 uses a multifaceted approach for the suppression of Fusarium oxysporum f. sp. ciceris and to enhance the biomass of chickpea plants

“…Similar to our study, a significant decrease in disease development in Bacillus treated cotton plants compared to control has been reported 41 . Previously, B. atrophaeus TS1 suppressed the infection of F. graminearum on wheat 50 . However, B. thuringiensis CHGP12 also showed an increase in total biomass of the chickpea plant indicating the dual role of CHGP12 in controlling the infection and promoting plant growth.…”

“…The hydrolytic enzymes produced by Bacillus species perform a dual role as they are not only involved in causing the direct lysis of the cell wall of fungi, but they can also improve the plant growth. In a similar study, it was reported that the inhibition of F. graminearum by B. atrophaeus TS1 was due to the production of hydrolytic enzymes 50 . These hydrolytic enzymes deliver energy to the germinating plants by solubilizing endospermic food stored in the food such as starch, lipid, and proteins 51 .…”

“…41 Previously, B. atrophaeus TS1 suppressed the infection of F. graminearum on wheat. 50 However, B. thuringiensis CHGP12 also showed an increase in total biomass of the chickpea plant indicating the dual role of CHGP12 in controlling the infection and promoting plant growth. In a previous report an increase in plant growth parameters was observed in B. phytofirmans PsJN treated maize, wheat, lettuce, and Acacia ampliceps.…”

“…In a similar study, it was reported that the inhibition of F. graminearum by B. atrophaeus TS1 was due to the production of hydrolytic enzymes. 50 These hydrolytic enzymes deliver energy to the germinating plants by solubilizing endospermic food stored in the food such as starch, lipid, and proteins. 51 Therefore, the antifungal and growth-promoting activity of CHGP12 can be attributed to the presence of hydrolytic enzymes.…”

Bacterial and Fungal Biocontrol Agents for Plant Disease Protection: Journey from Lab to Field, Current Status, Challenges, and Global Perspectives

“…However, the excessive use of chemical pesticides has resulted in environmental pollution, thereby limiting their use in the agricultural sector [ 3 , 4 ]. Currently, researchers are exploring the use of beneficial microorganisms as an eco-friendly strategy to control crop diseases [ 3 , 5 ]. A diverse range of bacterial genera have demonstrated great potential as biocontrol agents for various plant diseases.…”