Abiotic stress tolerance of microorganisms associated with oregano (Origanum vulgare L.) in the Yaqui Valley, Sonora

The impact of agricultural activities on microbial communities and environmental parameters was evaluated in two different soil samples. One sample corresponded to soil designated to oregano cultivation and the other one to native soil, both located in the Yaqui Valley, Sonora. The objective of this study was to estimate the microbial diversity in both soil samples, evaluating isolates obtained under three stress conditions: temperature, salinity and pesticide resistance, as well as using metabolic tests to evaluate their potential capabilities as plant growth promoting bacteria. The bacterial population was 5.9×10 and 3.8×10 CFU/g dry soil, in the native and oregano-designated soil, respectively. A total of twenty-four bacteria and one actinobacterium were isolated. Native soil microorganisms presented higher values for fungicide tolerance and indoleacetic acid production; however, temperature stress, salinity resistance, siderophore production and phosphate solubilization were higher for microorganisms isolated from the agricultural soil. These results demonstrate the impact of land use on microbial communities and their potential eco-functional roles.