Enhancement of Seawater Stress Tolerance in Barley by the Endophytic Fungus Aspergillus ochraceus

Abstract

Symbiotic plant-fungi interaction is a promising approach to alleviate salt stress in plants. Moreover, endophytic fungi are well known to promote the growth of various crop plants. Herein, seven fungal endophytes were screened for salt tolerance; the results revealed that Aspergillus ochraceus showed a great potentiality in terms of salt tolerance, up to 200 g L−1. The indole acetic acid (IAA) production antioxidant capacity and antifungal activity of A. ochraceus were evaluated, in vitro, under two levels of seawater stress, 15 and 30% (v/v; seawater/distilled water). The results illustrated that A. ochraceus could produce about 146 and 176 µg mL−1 IAA in 15 and 30% seawater, respectively. The yield of IAA by A. ochraceus at 30% seawater was significantly higher at all tryptophan concentrations, as compared with that at 15% seawater. Moreover, the antioxidant activity of ethyl acetate extract of A. ochraceus (1000 µg mL−1) at 15 and 30% seawater was 95.83 ± 1.25 and 98.33 ± 0.57%, respectively. Crude extracts of A. ochraceus obtained at 15 and 30% seawater exhibited significant antifungal activity against F. oxysporum, compared to distilled water. The irrigation of barley plants with seawater (15 and 30%) caused notable declines in most morphological indices, pigments, sugars, proteins, and yield characteristics, while increasing the contents of proline, malondialdehyde, and hydrogen peroxide and the activities of antioxidant enzymes. On the other hand, the application of A. ochraceus mitigated the harmful effects of seawater on the growth and physiology of barley plants. Therefore, this study suggests that the endophytic fungus A. ochraceus MT089958 could be applied as a strategy for mitigating the stress imposed by seawater irrigation in barley plants and, therefore, improving crop growth and productivity.

Potential of biosynthesized zinc oxide nanoparticles to control Fusarium wilt disease in eggplant (Solanum melongena) and promote plant growth

“…Peroxidase activity (POD) was assayed according to that method described by Bergmeyer and Bernt ( 1974 ) with modifications by Badawy et al ( 2021 ). Activity of polyphenol oxidase enzyme was calculated by the procedure used by Matta and Dimond ( 1963 ).…”

Inhibition of Aspergillus flavus Growth and Aflatoxin Production in Zea mays L. Using Endophytic Aspergillus fumigatus

“…Endophytic fungi are fungi that can grow in healthy plant tissues without any harmful effects on their host plants [ 32 , 33 ]. In general, leaves are the main source of the endophytic fungal community, promoting the effect on plant health [ 34 ]. The degree of microbial diversity of living host plants differs according to the plant species that have been described as protecting agents against biotic attacks [ 35 ].…”

Evaluation of Plant Growth-Promoting and Salinity Ameliorating Potential of Halophilic Bacteria Isolated From Saline Soil

“…A. ochraceus produced 146 and 176 µg/mL IAA in 15% and 30% seawater (Badawy et al, 2021), respectively. However, in the present study, IAA production and siderophore production results were comparatively higher than the yield cited in previous studies at high salt concentrations.…”