Enhanced growth and stress tolerance in Barley (Hordeum vulgare) through biopriming with Aspergillus niger CSR3: a promising approach for sustainable agriculture in saline environments

Barley ( Hordeum vulgare ) is the fourth largest cereal crop in the world, with considerable nutritional value. Recently more studies on the toleration of barley to salt stress have been published, indicating an increased concern for food safety. Salt stress is an increasing threat to agricultural productivity; thus, an attempt was made to explore the growth-promoting capacities of an endophytic fungal strain Aspergillus niger CSR3 in H. vulgare . In the current study, we investigated various physiological and biochemical characteristics of two H. vulgare varieties, namely OM-80 and OM-82, under 300 mM NaCl and 100% seawater treatments with and without the inoculation of CSR3. Our results showed that biopriming of H. vulgare seeds with CSR3 enhanced germination ratio both in control and salt treated conditions. Under salt stress, the growth of H. vulgare plants was significantly reduced; however, CSR3 alleviated the salt stress and significantly increased root/shoot length and weight compared to their respective counterparts both under control and stress conditions. The fungal strain showed an ameliorated response to salt stress by improving the photosynthetic machinery. Results demonstrate that accumulation of reduced glutathione (GSH), catalase (CAT), and flavonoids decreased in inoculated plants as compared to non-inoculated under saline conditions indicating the potential of CSR3 in maintaining cellular homeostasis against salinity stress. Moreover, our finding also revealed that starch accumulation decreased with a gradual increase of salt treatment; however, CSR3 inoculation enhanced starch and decreased sugar level, indicating its potential to convert excess sugar to starch. In conclusion, CSR3 can improve plant performance significantly and can greatly improve sustainable agricultural production in saline marginal lands.