Microbial communities evolve faster in extreme environments

Abstract

Evolutionary analysis of microbes at the community level represents a new research avenue linking ecological patterns to evolutionary processes, but remains insufficiently studied. Here we report a relative evolutionary rates (rERs) analysis of microbial communities from six diverse natural environments based on 40 metagenomic samples. We show that the rERs of microbial communities are mainly shaped by environmental conditions, and the microbes inhabiting extreme habitats (acid mine drainage, saline lake and hot spring) evolve faster than those populating benign environments (surface ocean, fresh water and soil). These findings were supported by the observation of more relaxed purifying selection and potentially frequent horizontal gene transfers in communities from extreme habitats. The mechanism of high rERs was proposed as high mutation rates imposed by stressful conditions during the evolutionary processes. This study brings us one stage closer to an understanding of the evolutionary mechanisms underlying the adaptation of microbes to extreme environments.

Metagenomic Analysis of Hot Springs in Central India Reveals Hydrocarbon Degrading Thermophiles and Pathways Essential for Survival in Extreme Environments

“…The enrichment of genes associated with DNA repair systems and homologous recombination have been well-reported in extreme environments (Xie et al, 2011; Jimenez et al, 2012). Some recent studies have shown that the evolutionary rate of microbial communities is governed by the environmental conditions (Gupta and Sharma, 2015), and microbes in extreme habitats evolve faster with extensive DNA repair system and high mutation rates to cope with the deleterious effects of environment on their genomes as compared to those in stable environments (Li et al, 2014). Despite having a higher abundance of pathways such as replication and nucleotide metabolism, lower species richness was observed in Tattapani which indicates that very few microbial species are able to adapt and survive in extreme conditions.…”

Microbial Activity Response to Solar Radiation across Contrasting Environmental Conditions in Salar de Huasco, Northern Chilean Altiplano

“…Biosynthesis of detoxifying enzymes or antioxidant molecules such as glutathione is among the biochemical mechanisms of tolerance reported (e.g., Wang et al, 2011; Albarracín et al, 2015a,b, 2016; Häder et al, 2015; Kurth et al, 2015). Li et al (2014) also described high relative evolutionary rates (rERs) of microbial communities from more extreme natural environments, where the microbes inhabiting extreme habitats (acid mine drainage, saline lake, and hot spring) evolved faster than those populating benign environments (e.g., surface ocean, fresh water, and soil). This high evolutionary rate was attributed potentially to more frequent horizontal gene transfer in communities from extreme habitats.…”

“…BSP responses (inhibition or enhancement) under short-term solar exposure cannot be only related to light exposure history, but also to some other extreme conditions (Rothschild and Mancinelli, 2001; Triadó-Margarit and Casamayor, 2012; Guerrero et al, 2013; Li et al, 2014). The irradiance conditions experienced by isolated pond communities in our experiments were in combination with other potentially limiting conditions.…”

Aerobic Lineage of the Oxidative Stress Response Protein Rubrerythrin Emerged in an Ancient Microaerobic, (Hyper)Thermophilic Environment

“…It is probable that during those “oxygen whiffs,” many proteins would be the object of selection pressure to survive in oxygen that could force them to lose or gain new features such as protein domains (Nasir et al, 2014) or physiological activities. In addition, the ancient hot environment of the Archaean eon could helped to accelerate the evolutionary rate of change of these proteins, as postulated to be occurring in current extreme environments (Li et al, 2014). Subsequently, an additional gene, RFO, was added that provided full function in aerobic environments perhaps resulting from GOE.…”