Microbial diversity in semiarid area determined by next generation sequencing

Our information on the soil microbial diversity especially in arid and semiarid areas, which cover ۴۰% of the earth area and more than ۷۰% of Iran area, is very limited. This study aimed to determine the impact of climate and grazing on the soil bacterial composition in two semiarid areas by next generation sequencing. Soil samples were taken from four zones which were either cold or warm and either grazed by cattle or not grazed in Khabr National Park and Ruchun Wildlife Refuge, Kerman province, Iran. Sequencing was done by Illumina Miseq platform after DNA amplification by ۲۷f-۵۱۸r primers. Data were analyzed by Qiime to determine bacterial community composition, diversity (Chao۱) and evenness (Shannon's H). The abundance of Proteobacteria (۲۸.۳%±۱.۰) and Actinobacteria (۴۴.۶%±۱.۱) was highest at the cold-grazed and warm-grazed zones, respectively, which account for ~۷۰% of all OTUs. Greater richness and less evenness of bacteria at the cold areas, compared to the warm areas, was also observed and is attributed to more vegetation cover and soil nutrient and organic matter availability and moisture improving bacterial growth. The significant differences were observed in the bacterial diversity between the grazed and not grazed sites due to the change in organic matter compounds resulting from animal waste. According to the Chao۱ and Shannon's H, the least richness and the highest evenness belonged to the warm-grazed zone, indicating grazing had a greater impact because of their fragile condition. Then warm areas need more scientific management as well as more attention to prevent sever damage

Keywords:

Climate , Bacteria , Grazing , V۱-V۳ region , Evenness