Torres-Diaz, C. | Search bioRxiv

bioRxiv2022

The global distribution and environmental drivers of the soil antibiotic resistome

BackgroundLittle is known about the global distribution and environmental drivers of key microbial functional traits such as antibiotic resistance genes (ARGs). Soils are one of Earths largest reservoirs of ARGs, which are integral for soil microbial competition, and have potential implications for plant and human health. Yet, their diversity and global patterns remain poorly described. Here, we analyzed 285 ARGs in soils from 1012 sites across all continents, and created the first global atlas with the distributions of topsoil ARGs. ResultsWe show that ARGs peaked in high latitude cold and boreal forests. Climatic seasonality and mobile genetic elements, associated with the transmission of antibiotic resistance, were also key drivers of their global distribution. Dominant ARGs were mainly related to multidrug resistance genes and efflux pump machineries. We further pinpointed the global hotspots of the diversity and proportions of soil ARGs. ConclusionsTogether, our work provides the foundation for a better understanding of the ecology and global distribution of the environmental soil antibiotic resistome.

ecology↗

bioRxiv2018

Root endophytes improve physiological performance and yield in crops under salt stress by up-regulating the foliar sodium concentration

Increase in the soil salinity will be a conspicuous constraint for both native plant communities as well as several crops worldwide. In this context plant root-associated fungi appear as a new strategy to improve ecophysiological performance and yield of crops under abiotic stress. Here, we evaluated how the inoculation of fungal endophytes isolated from Antarctic plants can improve the ecophysiological performance in cultivars of tomato and lettuce, grown under different salt conditions. In addition, we assessed if the expression of the NHX1 gene that is related with salt tolerance is enhanced in presence of fungal endophytes. Finally, we evaluated the regulation the nutritional status and specifically the Na+ content in leaves. Overall, those individuals with presence of endophytes showed higher ecophysiological performance. In addition, the presence of fungal endophytes was correlated with a higher regulation of ion homeostasis by enhanced expression of NHX1 gene. Our results suggest that presence of fungal endophytes could minimize the negative effect of salt by improving osmotic tolerance through ecophysiological and molecular mechanisms. Thus, root-endophytes might be a successful biotechnological tool to maintain high levels of ecophysiological performance and productivity in zones under osmotic stress, acting as potential solution to maintain the global food security.\n\nHighlightWe showed that functional symbiosis improve the physiological performance and yield in crops subjected to salinity, by biochemical and molecular mechanisms. Thus, here we pointed a successful strategy to meet the future challenges for help to maintain the food security.

plant biology↗