Analysis of thermal and drought tolerance conferred by endophytes in tomato plants

Tomato (Solanum lycopersicum L.) belongs to Solanaceae family. It is a valuable source of several mineral vitamins. The world food security is highly disturbed by the unpredictable drought and heat stresses which will upsurge in frequency and brutality in the near future leading to a probable decline in global food production. Improvement in drought tolerant varieties through plant breeding is a promising and effective approach but it is an expensive and also a long drawn procedure. Endophytic fungi inhabiting the root and shoot tissues can play key role in this regard. Hence the present research was undertaken out to evaluate the potential of fungal endophytes in tomato crop against thermal and drought stress. The experiment was conducted in research area of department of Plant Pathology, University of Agriculture Faisalabad during 2014-2015. Eight varieties of tomato were sown under randomized complete block design (RCBD) in pots and later on were transplanted to field. Endophytic fungus was isolated from healthy leaves, stems and roots of Acacia nilotica and Convulvulus arvensis was identified on the basis of morphology of fungal culture and spore characteristics. Inoculation was done by immersing the tomato seedlings in fungal suspension of concentration 10-5 spore mL-1. The endophytic fungi was reisolated and identified from the inoculated plants to confirm the colonization of the fungus in the plant tissues. Data regarding plant growth was recorded and subjected to analysis of variance and statistical difference between mean values or percentages was determined by the Student's t-test. The result of the experiment depicted that endophytic fungi had a positive influence on the growth of roots of treated crop and enhanced root length and weight significantly than the untreated check during water deficit conditions and heat stress. Data regarding shoot biomass also showed that endophytic fungi had a positive impact on shoot growth of treated tomato varieties. Results also depicted increased plant yield with the application of endophytic fungi in drought and heat stress conditions. Results also showed the negative interaction of certain fungi on various varieties. In these cases even after the application of endophytic fungi untreated check gave better results that the plots treated with endophytic fungi. A significant reduction had been observed in root and shoot biomass and also yield of crop.