Biology subjects

Fortt, J.

Publications and source records attributed to Fortt, J..

2 recordsLinked to original sources

bioRxiv2024

Rhizospheric bacteria from the Atacama Desert hyper-arid core: cultured community dynamics and plant growth promotion

The Atacama Desert is the oldest and driest desert on Earth, with environmental conditions including great temperature variations, high UV-radiation, drought, high salinity, making it a natural laboratory to study the limits of life and resistance strategies. However, it shows great biodiversity harboring vast forms of adapted life and can be used as a model of desertification processes. While desertification is increasing as result of climate change and human activities, is necessary to optimize soil and water usage, where stress-resistant crops are possible solutions. As many studies have revealed the great impact of rhizobiome over plant growth efficiency and resistance to abiotic stress, we set up to explore the rhizospheric soils of Suaeda foliosa and Distichlis spicata from the Atacama Desert. By culturing these soils and using 16S rRNA amplicon sequencing, we address the community taxonomy composition dynamics, the stability through time and the ability to promote lettuce plants growth. The rhizospheric soil communities were dominated by the families Pseudomonadaceae, Bacillaceae and Planococcaceae for S. foliosa and Porphyromonadaceae and Haloferacaceae for D. spicata. Nonetheless, the cultures were completely dominated by the Enterobacteriaceae family (up to 98%). Effectively, lettuce plants supplemented with the cultures showed greater size and biomass accumulation, we identify 12 candidates that could be responsible of these outcomes, of which 5 (Enterococcus, Pseudomonas, Klebsiella, Paenisporosarcina and Ammoniphilus) were part of the built co-occurrence network, being Klebsiella a major participant. We aim to contribute to the efforts to characterize the microbial communities as key for the plants survival in extreme environments, and as a possible source of consortia with plant growth promotion traits aiming agricultural applications. IMPORTANCEThe current scenario of climate change and desertification represents a series of incoming challenges for all living organisms, also as the human population grows rapidly, so is rising the demand for food and natural resources; thus, it is necessary to make agriculture more efficient by optimizing soil and water usages thus ensuring future food supplies. Particularly, the Atacama Desert (northern Chile) is considered the most arid place on Earth as a consequence of geological and climatic characteristics, such as the naturally low precipitation patterns and high temperatures, which makes it an ideal place to carry out research that seeks to aid agriculture to the future sceneries, which are predicted to resemble these. The use of microorganism consortia from plants thriving under these extreme conditions to promote plant growth, improve crops and make "unsuitable" soils farmable is our main interest. TWEETCultures of rhizospheric soils from Atacama Desert resilient plants were enriched in Klebsiella, Bacillus and Brevibacillus which promoted lettuce growth

microbiology↗

bioRxiv2021

Living to the high extreme: unraveling the composition, structure, and functional insights of bacterial communities thriving in the arsenic-rich Salar de Huasco - Altiplanic ecosystem.

Microbial communities inhabiting extreme environments like Salar de Huasco (SH) are adapted to thrive while exposed to several abiotic pressures and the presence of toxic elements like arsenic (As). Hence, we aimed to uncover the role of arsenic in shaping bacterial composition, structure, and functional potential in five different sites in this Altiplanic wetland using a shotgun metagenomic approach. The sites exhibit wide gradients of arsenic (9 to 321 mg/kg), and our results showed highly diverse communities and a clear dominance exerted by the Proteobacteria and Bacteroidetes phyla. Functional potential analyses showed broadly convergent patterns, contrasting with their great taxonomic variability. Arsenic-related metabolism is different among the five communities, as well as other functional categories like those related to the CH4 and S cycles. Particularly, we found that the distribution and abundance of As-related genes increase, following along the As concentration gradient. Approximately 75% of the detected genes for As-metabolism belong to expulsion mechanisms, being arsJ and arsP pumps related to sites with higher As concentrations and present almost exclusively in Proteobacteria. Furthermore, taxonomic diversity and functional potential are reflected in the 12 reconstructed high-quality MAGs (Metagenome Assembled Genomes) belonging to the Bacteroidetes (5), Proteobacteria (5), Cyanobacteria (1) and Gemmatimonadota (1) phyla. We conclude that SH microbial communities are diverse and possess a broad genetic repertoire to thrive under extreme conditions, including increasing concentrations of the highly toxic As. Finally, this environment represents a reservoir of unknown and undescribed microorganisms, with a great metabolic versatility, which needs further study. IMPORTANCEMicrobial communities inhabiting extreme environments are fundamental for maintaining the ecosystems; however, little is known about their potential functions and interactions among them. We sampled the microbial communities in Salar de Huasco (SH) in the Chilean Altiplano, a fragile and complex environment that comprises several stresses. We found that microbes in SH are taxonomically diverse; nonetheless, their functional potential seems to have an important convergence degree, suggesting high adaptation levels. Particularly, arsenic metabolism showed differences associated with increasing concentrations of the metalloid throughout the area, and it is effectively exerting a clear and significant pressure over these organisms. Thus, this researchs significance is that we described highly specialized communities thriving in little-explored environments under several pressures, considered analogous of early Earth and other planets, and can have the potential for unraveling technologies to face climate change repercussions in many areas of interest.

microbiology↗