بررسی اثر باکتری‌های اندوفیت در بیوکنترل قارچ Alternaria alternata عامل بیماری لکه موجی در سیب زمینی های بذری تولیدی در گلخانه های آیروپونیک

Potato with the scientific name Solanum tubersum is one of the agricultural products with high nutritional value and widely consumed in the world. In terms of the amount of production in the world, it ranks fourth after wheat, corn and rice. Excessive consumption of water and decrease in rainfall have caused water shortage to become a serious and important crisis. To deal with this problem, the development of different cultivation and irrigation systems in agriculture is being done. One of these systems is aeroponic cultivation and seed potato production in this way. One of the important diseases and one of the limiting factors of potato cultivation is early blight disease caused by Alternaria fungus. Due to the emergence of new agricultural systems and the emphasis on organic and sustainable agriculture, biological control is widely used as one of the appropriate approaches to control and combat against plant diseases, and the knowledge of biological control is developing rapidly all over the world. Many studies have been conducted to highlight the ability of endophyte antagonists to impact important plant characteristics such as disease resistance, plant growth, tolerance to abiotic stresses, etc. In the present study, 60 endophyte bacterial isolates were isolated from healthy tubers of seed potatoes. In order to investigate the antagonistic ability of endophyte isolates, dual culture was used, among which ten isolates showed significant antagonistic effects (creating an inhibition zone of more than 1 cm) against the pathogen. Moreover, in the test of volatile compounds in upside-down Petri dishes, the isolates only changed the mycelial color of Alternaria after one week. Also, in evaluating the effect of the suspension without bacterial cells, a liquid culture medium including cell-free bacteria with a concentration of 10% was added to the PDA culture medium and the growth rate of the fungal pathogen was checked. All 10 selected isolates have significantly inhibited the growth of the fungal pathogen compared to the control (more than 50% growth inhibition). It seems that, 10 bacterial isolates are proper choices for controlling potato early blight, but more additional tests and testing the isolates under greenhouse conditions are necessary in order to select the best isolates.