Free-air CO2 enrichment (FACE) enhances the biodiversity of purple phototrophic bacteria in flooded paddy soil

Abstract

Purple phototrophic bacteria (PPB) are thought to be crucial in the nutrient cycling of rice field. However, it remains unclear how PPB would respond to the climate change associated with the projected atmospheric CO 2 in the future. A factorial design of field experiments was set up with two levels of atmospheric CO 2 concentration (350 and 550 μmol mol −1 ) and N application rate (150 and 250 kg N ha −1 ) to investigate the abundance and composition changes of PPB in rhizospheric and bulk soils in response to the rising atmospheric CO 2 concentration. Based on denaturant gradient gel electrophoresis (DGGE) analysis of pufM gene encoding the M subunit of anoxygenic PPB light reaction center, elevated CO 2 appeared to enhance the biodiversity of PPB in flooded paddy soils. This was further supported by canonical correspondence analysis (CCA) of DGGE fingerprinting pattern of pufM genes in paddy soils as well as Shannon diversity indices. Real-time quantitative PCR analysis of pufM gene further indicated that PPB abundance was stimulated by elevated CO 2 in bulk soil, while the contrasting result was observed in rhizospheric soil. Our result for the first time demonstrated that elevated CO 2 enhanced the biodiversity of PPB within α and β subdivisions of Proteobacteria.

Diversity of Phototrophic Genes Suggests Multiple Bacteria May Be Able to Exploit Sunlight in Exposed Soils from the Sør Rondane Mountains, East Antarctica

“…The remainder of the PufM diversity in our samples, although recovered in small relative numbers, also mainly related to aquatic photoheterotrophic taxa. However, several of the PufM sequences recovered (e.g., Methylobacterium -like, Rhodopseudomonas -like) were highly similar to PufM reported from Arctic soils (Feng et al, 2014) or Chinese paddy soils (Feng et al, 2009, 2011a,b,c). Thus, although aerobic anoxygenic phototrophy is frequently studied in aquatic environments, our data strongly suggest that this lifestyle may potentially be important in terrestrial ecosystems.…”

Diversity of aerobic anoxygenic phototrophic bacteria in paddy soil and their response to elevated atmospheric CO2

“…reveal that elevated atmospheric CO2 leads to the increases in SOC by 14% (Feng et al, 2009) and dissolved organic C (DOC) by 42% (Cheng et al, 2010) in paddy soil. This process might enhance the bioavailability of organic matters and final stimulate the heterotrophic growth of AAnPB in paddy soil.…”

The impact of iron oxide magnetic nanoparticles on the soil bacterial community

“…The detailed protocol was described previously by Feng et al (2009). Briefly, the copy number of soil bacterial 16S rRNA genes was quantified by qPCR analysis with an Opticon 2 continuous fluorescence detection system (MJ Research).…”