Effects of Rice Straw Mulching on the Community Structure and Diversity of phzF-containing Pseudomonas fluorescens in Soil

The soil samples were taken from the long-term rice-straw mulching experiment in Taoyuan Agro-ecosystem Research Station. The diversity and community composition structure of soil Pseudomonas fluorescens containing phenazine biosynthesis gene (phzF) were investigated by terminal restriction fragment length polymorphism (T-RFLP) technique. The objective of this study was to understand the responses of phzF-containing P. fluorescens to long-term rice-straw mulching practice. The results showed that low rates of rice straw mulching(LRS) had little influence on the community composition structure of phzF genes, but the middle and high rates (MRS and HRS) resulted in significant changes of the relative abundance of the dominant phzF T-RFs. Redundancy analysis(RDA) indicated that these variations were closely linked to the soil available potassium contents. Among the rice straw mulching treatments, only MRS caused obvious increase of the diversity of phzF-containing P. fluorescens community. It can be suggested that using 10000 kg/hm2 of rice straw would be a suitable amount for habitating the anti-pathogens of P. fluorescens, and as a consequence, soil borne disease might be reduced. The results would be benefit to the understanding the mechanisms of agricultural management on soil anti-pathogenic microorganism.