Drought tolerant bacterial endophytes with potential plant probiotic effects from Ananas comosus

Endophytic bacteria with multi-trait plant probiotic features have been demonstrated to have applications to enhance agricultural productivity by supporting the plant growth, yield and disease resistance under harsh environmental conditions. The xerophytic plant Ananas comosus was selected as the source for endophytic bacterial isolation in the current study. This has resulted in the identification of organisms with antifungal and plant growth promoting properties. Interestingly, endophytic bacteria with antifungal activity were found to have drought tolerance property also. These organisms were demonstrated to express the plant beneficial mechanisms like IAA, ACC deaminase and nitrogen fixation under drought condition. The selected organisms were further identified as Bacillus sp. (Acb9), Providencia sp. (Acb11), Staphylococcus sp. (Acb12), Staphylococcus sp. (Acb13) and Staphylococcus sp. (Acb14)(Acb 14). In addition, LC-MS/MS analysis of extract from Acb 9 has resulted in the identification of surfactin with m/z of 994. Priming of selected endophytes with Vigna radiata seedlings also showed enhanced growth parameters such as shoot length, root length and root numbers when compared to the control. The shoot length of Acb 9 treatment was found to be 18.833 +/- 0.687 cm, where the control value for same was 13.976 +/- 0.585 cm and the root length was 3.9 +/- 0.99 when compared to control (1.54 +/- 0.628). The root length was 3.9 +/- 0.99 which was also higher than control (1.54 +/- 0.62).The results of the study indicate the promise of endophytic bacteria for field application under changing agro-climatic conditions.