| Congresso Brasileiro de Microbiologia 2023 | Resumo: 892-2 | ||||
Resumo:Restinga is a coastal ecosystem with a mosaic of vegetation that covers marine sand deposits, spanning 5,000 km along the Brazilian coastlines. Despite the low fertility of restinga soils due to high sand concentration, low water availability, and other environmental factors, restingas display remarkable plant diversity and endemism. Soil microorganisms play a vital role in nutrient cycling and may promote plant growth through metabolic processes such as nitrogen fixation and the production of phytohormones. However, water availability can significantly impact the microbial distribution, its metabolic activity, and ecological interactions between plants and microorganisms. Our hypothesis is that water availability in restinga soils can modulate the microbial community. To investigate this hypothesis, soil samples were collected in triplicate from plant thickets (IM) and bare soil areas between plant thickets (EM) in the Costa do Sol State Park (Massambaba Environmental Protection Area), located in the city of Arraial do Cabo - RJ. These samples were obtained during two distinct periods: the before-rainy period (IMS and EMS) and the post-rainy period (IMC and EMC). The physical-chemical analysis revealed higher soil moisture in IMS than in EMS, and higher moisture in IMC than in EMC. Additionally, the moisture in IMC was higher than in IMS, and the organic matter concentration was lower in IMC than in IMS. The qPCR analysis of the gene coding for 16S rRNA showed no significant difference between IMS and IMC, and between EMS and EMC samples; however, sequencing of the 16S rRNA coding-gene revealed significantly higher prokaryotic diversity in EMS and EMC compared to IMS and IMC soils (p < 0.05). Furthermore, prokaryotic diversity was higher in IMC than in IMS (p < 0.05). β-diversity analysis showed the composition and structure of the microbiome present in EMC was not statistically different from the microbiome observed in EMS. On the other hand, the microbiome present in IMC was significantly different from microbiome obtained from IMS (Weighted Unifrac, p < 0.05). Regarding taxonomy analysis, in general, the phyla Actinobacteriota, Proteobacteria, and Acidobacteriota were the most abundant in both IM and EM samples. The genus Acidothermus and an unidentified genus from the family Acetobacteraceae showed higher relative abundance in IMS and IMC soils, while the relative abundance of genera Conexibacter and Bryobacter was higher in the EMS and EMC samples. Overall, this study aimed to explore the intricate relationships between water availability, microbial communities, and plants in restinga ecosystems. The results revealed that water availability can influence the composition and diversity of microbial communities, impacting their interactions with plants and potentially affecting the growth and stability of plants in restinga regions. These findings contribute to the understanding of ecosystem dynamics in coastal environments and offer important implications for biodiversity conservation, ecosystem restoration, and soil management strategies to improve the soils in degraded areas and in similar environments worldwide. Palavras-chave: restinga, soil microorganisms, soil fertility, water availability Agência de fomento:Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro - FAPERJ | |||||