Study of the interaction of two soil fungal isolates with Arabidopsis thaliana

Abstract

This current study aimed to evaluate the ability of two soil fungal isolates, individually or in combination, to promote the growth of Arabidopsis thaliana col 0 and their potential to mitigate salt stress. The two fungi were isolated from two different soils, and were identified, microscopically, as belonging to the genus Aspergillus. The study of their salinity tolerance indicated that both fungi were halotolerant, with a wide range of NaCl tolerance, ranging from 0 to 20% (m/v). However, they exhibited an optimal growth at 5% (m/v) of NaCl. Four experimental treatments were applied for A. thaliana plants: a control group, without fungi, a group treated with Aspergillus sp.1 and Aspergillus sp.2, under three NaCl concentrations (0, 75, and 100 mM), and a group treated with a mixture of both, at 0 and 75mM of NaCl. The following growth parameters were measured: primary root length, number of secondary roots and leaves, fresh weight, and chlorophyll “a”, “b”, and total chlorophyll concentrations. The results were analysed using Welsh’s ANOVA (with two factors) and the Games-Howell test for post hoc comparisons. The results showed that all fungal treatments led to significant improvements in growth parameters (p  0.05) compared to the control group. The effect of Aspergillus sp.1 was more pronounced than the other treatments, especially at a concentration of 75 mM, while the fungal mixture showed no synergistic effect. These results indicate that Aspergillus sp.1 has great potential, not only to promote the growth of Arabidopsis thaliana, but also to mitigate the negative effects of salt stress, making it a promising candidate as an inoculant to improve sustainable agricultural systems and mitigate the negative effects of salinity without causing any negative environmental impact.