O solo está repleto de vírus. Crédito: Stephanie King | Laboratório Nacional do Noroeste do Pacífico
Cientistas do PNNL descobrem novos vírus do solo
O herói desconhecido de nossas vidas é o solo. Ela nutre as plantações para alimentar os humanos, drena as chuvas para os aquíferos e serve como habitat para uma variedade de organismos. Em um nível microscópico, o solo está repleto de microrganismos, como fungos e bactérias, que cooperam com as plantas. Apesar de ser um aspecto tão crucial da nossa existência, pouco se sabe sobre o que está abaixo da superfície da Terra.
Cientistas do Pacific Northwest National Laboratory (PNNL) empregaram bioinformática e sequenciamento profundo para detectar vírus do solo e entender melhor seus papéis na Terra em novas pesquisas. A maioria desses vírus infecta bactérias e, consequentemente, assume-se que desempenham um papel fundamental na manutenção da população microbiana.
“Os vírus são abundantes na natureza”, disse Janet Jansson, cientista-chefe de biologia e bolsista do PNNL Laboratory. “Como há muitos deles em cada amostra de solo, identificar diferentes vírus se torna um desafio.”
Jansson trabalhou com o cientista computacional Ruonan Wu e a cientista da Terra e líder da equipe de ciências do microbioma Kirsten Hofmockel na Divisão de Ciências Biológicas do PNNL para enfrentar esse desafio.
Junto com colaboradores da Washington State University; Universidade de Saúde e Ciências de Oregon; Universidade Estadual de Iowa; e EMSL, o Laboratório de Ciências Moleculares Ambientais, uma instalação de usuários do Departamento de Energia do Escritório de Ciências do PNNL; os cientistas do PNNL coletaram amostras de solo de pastagens em Washington, Iowa e Kansas e começaram um mergulho profundo na composição do solo. Eles aproveitaram a enorme[{” attribute=””>DNA sequencing abilities of the Joint Genome Institute, computing power of the National Energy Research Scientific Computing Center, and multi-omics expertise from EMSL to unearth previously unknown soil viruses. Their results were published in mBio and Communications Biology.
From left to right: Janet Jansson, Ruonan Wu, and Kirsten Hofmockel pioneer research on soil viruses. Credit: Shannon Colson | Pacific Northwest National Laboratory
Different viruses for different climates
Because each site receives a varied amount of rainfall, the scientists picked Washington, Iowa, and Kansas for their soil samples. Eastern Washington is substantially drier than Iowa, whereas Kansas lies in the middle between the two in terms of soil moisture.
“We chose to take samples from places with different amounts of soil moisture to see if this made a difference in the types and amounts of viruses there,” said Wu. “Wetter soil contains more bacteria, and many soil viruses infect bacteria.”
The scientists noticed that certain viruses are much more abundant in dry soil than wet soil.
“In drier climates, there tend to be fewer, but more diverse, microbes in the soil,” said Wu. “The relative scarcity of bacterial hosts means that it’s in the virus’s best interest to keep the host alive.”
The researchers also discovered that in drier soil, viruses were more likely to contain special genes that they could potentially transfer to their bacterial hosts.
“These genes could potentially give their bacterial hosts ‘superpowers’” said Jansson. “These virus genes could be passed to their bacterial hosts to help them survive in dry soils.”
Though more research is necessary to better understand the role of these special viral genes, the possibility that they could be useful to bacteria living in the soil is exciting. These genes could be useful to bacteria by increasing their ability to recycle carbon and thus increase soil health.
This work was supported by the Department of Energy’s Office of Science Biological and Environmental Research program. This is a contribution of the scientific focus area “phenotypic response of the soil microbiome to environmental perturbations.” Portions of this research were performed by EMSL, the Joint Genome Institute, and the National Energy Research Scientific Computing Center at the Lawrence Berkeley National Laboratory.
References: “Moisture modulates soil reservoirs of active DNA and RNA viruses” by Ruonan Wu, Michelle R. Davison, Yuqian Gao, Carrie D. Nicora, Jason E. Mcdermott, Kristin E. Burnum-Johnson, Kirsten S. Hofmockel and Janet K. Jansson, 26 August 2021, Communications Biology.
DOI: 10.1038/s42003-021-02514-2
“DNA Viral Diversity, Abundance, and Functional Potential Vary across Grassland Soils with a Range of Historical Moisture Regimes” by Ruonan Wu, Michelle R. Davison, William C. Nelson, Emily B. Graham, Sarah J. Fansler, Yuliya Farris, Sheryl L. Bell, Iobani Godinez, Jason E. Mcdermott, Kirsten S. Hofmockel and Janet K. Jansson, 2 November 2021, mBio.
DOI: 10.1128/mBio.02595-21
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