Protective role of biomass endophytic fungi to enhance potato plant responses against wilt disease caused by Ralstoniasolanacearum

Abstract

Globally, Ralstonia solanacearum wilt disease significantly reduces the value of tomatoes, eggplants, bananas, and potatoes. In this study, endophytic fungi were isolated and used as biopesticides against the bacterial pathogen Ralstonia solanacearum in potato plants, offering a promising alternative to chemical pesticides that harm the environment. Aspergillus niger, Alternaria burnsii, and Aspergillus niveus were used in this study to support potato growth, combat Ralstonia solanacearum wilt (RSW) disease, and induce defense mechanisms and growth-promoting tactics in potato plants. The mix of A. burnsii, A. niveus, and A. niger was the most effective treatment in reducing the percent disease index (PDI) with an 18 % decrease compared to the infected control. This was followed by treatments with A. niger and A. niveus, which had PDIs of 32 % and 35 %, respectively. The next best treatment was with A. burnsii alone, resulting in a PDI of 61 %. Treatment with mixed filtrates from A. burnsii, A. niveus, and A. niger showed the greatest significant increase in shoot length by 251.9 %, root length by 38.1 %, and the number of leaves by 40.5 %. A clear and noticeable improvement in the levels of chlorophyll and carotene pigments was observed in plants treated with the tested endophytic fungi compared to those in infected plants. The infected plants treated with a mix of endophytic fungi showed a 94.1 % increase in free proline compared to untreated infested plants. Endophytic fungi can be applied alone or in combination to increase the number and density of antioxidant enzymes isozymes (PPO and POD)in both infected and uninfected plants. The study results suggested using mixed filtrates from A. burnsii, A. niveus, and A. niger as growth inducers for potato plants and as bioagents to control R. solanacearum wilt disease.