In SA treatments, PPO response with or check details without stress conditions was irregular. Although, PPO activity
was comparatively lesser in SA+EA plants, it followed the same trend as we observed in EA plants. P. resedanum association and SA-dependent responses under abiotic stress We also assessed the effect of endophytic elicitation with or without the treatment of SA on endogenous SA level. The results showed that SA was significantly find more low in non-stressed control. However, the stress periods has increased the endogenous SA levels (Figure 7). Similarly, in endophyte-associated plants, the endogenous SA was significantly higher than control under normal growth conditions. While after 2 days stress, its level in-significantly increased. The 4 and 8 days stress significantly increased SA contents in EA plants. This level was significantly higher than that of control and SA treated plants. In sole SA treatments, the plant synthesized GANT61 purchase low level of SA without any stress. However, upon 2 and 4 days stress, the SA level increased significantly while after 8 days, it decreased. In case of SA+EA plants, the endogenous SA followed the
same trend as we noticed in sole SA treatments, however, the quantity of SA synthesized was significantly higher during similar conditions (Figure 7). The overall SA biosynthesis pathway activation in sole SA was lower than EA and SA+EA plants. The EA and SA+EA plants have significantly activated endogenous SA biosynthesis Epothilone B (EPO906, Patupilone) with or without stress conditions. Figure 7 Endogenous salicylic acid (SA) synthesis of pepper plants inoculated with or without P. resedanum under osmotic stress and normal growth conditions.
EA = infected with P. resedanum; SA = treated with SA; SA+EA = endophytic fungal associated plants treated with SA. NST, 2-DT, 4-DT and 8-DT represent non-stressed, 2, 4 and 8 days drought stressed plants respectively. The different letter (s) in each stress period showed significant difference (P<0.05) as evaluated by DMRT. Discussion Endophyte-association helps in biomass recovery The results of the present study support and give additional information on the mechanism of endophyte’s ameliorative potential during abiotic stress to crop plant. The results revealed that endophyte-association rescued growth of pepper plants during stress by increasing shoot length. Plant-fungus relationship has been proclaimed a pivotal source for plant growth and development [30, 31]. Endophytic fungi have been regarded as plant protectant and growth regulator during normal and extreme environmental conditions [15–20, 31–33]. Various novel endophytic fungal species like Piriformospora indica, Neotyphodium sp., Curvularia protuberate, and Colletotrichum sp. etc [19, 20, 31, 32, 34] have been known to improve plant growth during abiotic stress conditions. Penicillium species have been known as a vital source for bioactive secondary metabolites [35].