Spatial And Temporal Distribution Of Virioplankton And Genetic Diversity Of G20 Gene In Napahai Wetland

Virioplankton is an important part of microbial food loop. Viral lytic process and infection play an important role in the carbon cycle and nutrition circulation of wetlands, and it mediates the exchange of genetic material of microbial communities, influences the genetic diversity, and community structure of microbial host. Napahai wetland is an unique seasonal plateau wetland with low-latitude and high-altitude, and an important base to carry out geological and biological research. However, the research on spatial and temporal distribution of virioplankton in Napahai plateau wetland is few reported.This study detected the abundance of culture-independent virioplankton in water and soil samples collected from Napahai plateau wetland in dry season of 2013 and rainy season of 2014. From the point of horizontal distribution, the virioplankton abundance of water samples (2.91×108/mL) is higher than that of soil samples (1×107 /mL). From the point of vertical distribution, the virioplankton abundance of soil in 10 cm (8.18×107/mL) is higher 3 to 5 times than that in 20 cm and 30 cm. From the point of seasonal distribution, in addition to the individual special samples, the rainy season is significantly higher than the dry season. The correlation analysis showed that the virioplankton abundance of soil in the dry season was significantly correlated (P<0.01) with planktonic bacteria abundance, organic matter, hydrolyzed nitrogen and total nitrogen, among were positively correlated with planktonic bacteria. The virioplankton abundance of soil in rainy season mainly was significant correlation (P<0.01) with soil total nitrogen, available phosphorus, potassium and calcium. In dry season, the virioplankton abundance of water samples was significantly correlated with planktonic bacteria abundance and concentration of Chlorophyll a (P<0.05), among are positively correlated with planktonic bacteria, while negative correlation with concentration of Chlorophyll a. It showed that the dominant population in the dry season was bacteriophage rather than cyanophage. Virioplankton abundance of water samples in the rainy season was significant correlated with pH value and temperature (P<0.01). The linear regression equation for the virioplankton abundance in two seasons and environmental factor were set up with R language software, and provided the mathematical model for improving and protecting the local phage resources.In order to detect the genetic diversity of cyanophage, the conserved genes degenerate primers were used to amplify g20 gene. It showed that 26 different cloning sequences were amplified from water samples collected from Napahai plateau wetland in rainy season. The study indicated that Napahai plateau wetland has abundance and unique genetic diversity of cyanophge, and two unique cyanophage groups were obtained, that’s Ⅰ and Ⅱ, while other sequences widely distribute in different environment by UniFrac software and phylogenetic analysis. It provided an effective method and technology for further clarifying the distribution of various bacteriophage groups in Napahai plateau wetland.The virioplankton and bacteria abundance with flow cytometry technology and genetic diversity of g20 gene in cyanophge of Napahai plateau wetland were systematically studied. It was an important supplement for the ecological study of Napahai plateau wetland, and also provided theoretical basis for the protection of the Local microbial resources.