Trends in Microbiome and Digital One Health

Soil salinity presents a significant environmental challenge, especially in arid and semi-arid regions worldwide, with a particular focus on the Middle East. This issue extends beyond the soil itself, affecting groundwater quality, agricultural productivity and the overall well-being of ecosystems. To effectively address and mitigate these adverse effects, it is essential to deepen our understanding of microbial diversity in these regions, as certain specialized microbial members have evolved to thrive under these challenging conditions. Within hypersaline ecosystems, members of the Bacillota phylum, notably the Bacillales order, have emerged as dominant presences. Bacillus paralicheniformis and B. licheniformis, in particular, stand out, showcasing pathways linked to salt tolerance, such as amino acids and fatty acids, as well as oxidative stress tolerance through polyamine production. The use of saline groundwater for irrigating farms has a significant impact on bacterial and fungal communities in arid soil, as well as on plant roots, with these effects being influenced by the electrical conductivity of the water. Notably, when farms are irrigated with saline water, a higher proportion of unique bacterial and fungal OTUs are present compared to the use of fresh water. Additionally, the richness of bacterial and fungal species in farms irrigated with saline groundwater is lower, and the communities exhibit distinct patterns that are influenced by water electrical conductivity (EC) and pH levels. The selection of specific microbial taxa under saline groundwater irrigation likely plays a role in mitigating salinity stress and promoting the growth of host plants. These findings offer valuable insights into the concept of "salinity filtering," shedding light on how it influences bacterial communities, key taxa, and their potential metabolic functions in soil. Furthermore, results have broad implications for arid agroecosystems, as they provide a foundation for understanding and addressing salinity-related challenges in agriculture and ecosystem management.