Effect of endophytic fungi in combating salinity and drought stress in date palm: A case study in Saudi Arabia

Abstract

Salinity and drought are among the major abiotic stresses, leading to decreased crop productivity. Fungi are notorious for their detrimental effects on crop growth and development. In light of these circumstances, the primary objective of this project is to assemble a collection of endophytic fungi to develop new organic bio-stimulants that can effectively combat salinity and drought. To achieve this goal, diverse soil types, including cultivated, desert, and salt marshes, were sampled (five samples each) from different habitats and locations in the southern part of Sinai, the Saint Katherine Protectorate (SKP) is part of the upper Sinai massif, spanning specific coordinates (33°550 to 34°300 E and 28°300 to 28°350 N). Additionally, 80 samples of the predominant medicinal plant species from ten localities in the SKP were collected. The results of survey showed that the highest abundance of endophytic fungi was observed in Artemisia judaica L. and Alkanna orientalis (L.) Boiss., with both species exhibiting 61.1 % endophytic fungi. Five isolates of fungi labeled as SAF41, SAF46, SAF51, SAF57, and SAF63, were assessed for their tolerance to salinity stress by exposing them to different NaCl concentrations. Isolate SAF63 had the most substantial negative and significant correlation with salinity stress (R2=0.9565; p<0.001), followed by SAF51 (R2=0.9432; p<0.001) and SAF41 (R2=0.9351; p<0.001). The results indicate that different fungi isolates exhibited distinct responses to varying salinity levels and drought stress, as measured by their growth in different NaCl concentrations. Isolate SAF63 demonstrated the most significant negative correlation with salinity stress, followed by SAF51 and SAF41. These findings suggest that specific endophytic fungi isolates exhibit enhanced tolerance to both salinity and drought stress, underscoring their promising potential in mitigating metabolic and physiological damage in date palm plants, ultimately leading to increased growth and yields