Rhizodeposition assembles a distinct bacterial microbiota in wheat rhizosphere

In this study, researchers report an integrative methodology in which stable isotope probing (SIP) and high-throughput pyrosequencing are combined to completely characterize the root-feeding bacterial communities in the rhizosphere of wheat grown in historical soils under three long-term (32-year) fertilization regimes. They find that wheat root-derived 13C is dominantly assimilated by Actinobacteria and Proteobacteria (notably Burkholderiales), accounting for nearly 70% of root-feeding microbiome. The results further reveal that long-term fertilizations with increasing nutrients availability would decrease the preference of rhizosphere microbiome for root-derived substrates, leading to a simpler crop-microbe association. This is a striking result, which means that long-term fertilization practices, inorganic fertilization in particular, are likely to decrease the probiotic functions of rhizosphere microbiota through simplifying the plant-microbe relationship, because the sub-community induced by the rhizodeposits contains diverse plant growth-promoting rhizobacteria (PGPR). In addition, researchers find that alterations of the soil bacterial community composition caused by the application of inorganic fertilizers can be resumed through the addition of organic manure, which provides a new theoretical basis for the long-term application of organic manure.

More details are available on the bellow links:
http://www.sciencedirect.com/science/article/pii/S0038071714003368
 

By Zhou Wei
zhouwei@caas.cn