Study On The Diversity Of Uncultured Actinomycetes In Saline-alkali Soil From Hexi Corridor

In order to understand the population structure and the diversity of actinomycetes in saline-alkali soils from Hexi corridor, the total DNA was extracted from saline-alkali samples and actinomycetes of 16 S rRNA gene clone libraries were constructed by amplifying 16 S rRNA gene primers with actinomycetes specific primers. Moreover, the positive clone products were digested by Hae Ⅲ and HhaⅠ; the clones with different types of electrophoretic bands were sequenced; diversity index was analyzed and the phylogenetic trees were built.The results showed that: modified high-salt method was suitable for genomic total DNA extraction from Saline-alkali soil in Hexi corridor by comparing four methods of genomic total DNA extraction of actinomycetes in saline-alkali soils. With analyses of actinomycetes diversity index in saline-alkali soil from the Hexi corridor, actinomycetes diversity of Shule river basin was the primary saline alkali soil>secondary saline-alkali soil>farmland soil; soil actinomycetes diversity of Heihe basin was secondary saline-alkali soil>primary saline-alkali soil; actinomycetes diversity of Shiyang river basin was secondary saline alkali soil>primary saline-alkali soil>farmland soil.The results of phylogenetic analyses of 16 S rRNA gene sequences from actinomycetes in three types of soil in Hexi Corridor Region of Shule River Basin indicated that: actinomycetes of the primary saline-alkali soil(S1) belonged to five suborders of Micrococcineae, Propionibacterineae, Corynebacterineae, Frankineae, Pseudonocardineae and unknown actinomycetes group; actinomycetes of secondary saline-alkali soil(S2) belonged to two suborders of Micrococcineae and Propionibacterineae as well as the unknown group of actinomycetes; actinomycetes of farmland soil(S3) belonged to two suborders of Micrococcineae and Corynebacterineae. In Heihe River Basin of Hexi Corridor Region, actinomycetes of the primary saline-alkali soil(S4) belonged to four suborders of Micrococcineae, Propionibacterineae, Corynebacterineae and Streptomycineae as well as the unknown group of actinomycetes; actinomycetes of secondary saline-alkali soil(S5) belonged to six suborders of Micrococcineae, Propionibacterineae, Streptomycineae, Micromonosporineae, Corynebacterineae and Pseudonocardineae as well as the unknown groups of actinomycetes. In Shiyang river basin of Hexi corridor region, actinomycetes of the primary saline-alkali soil(S6) belonged to five suborders of Micrococcineae, Frankineae, Propionibacterineae, Streptomycineae and Corynebacterineae as well as the unknown groups of actinomycetes; actinomycetes of secondary saline-alkali soil(S7) belonged to seven suborders of Micrococcineae, Frankineae, Propionibacterineae, Micromonosporineae, Pseudonocardineae, Streptomycineae and Streptosporangineae as well as the unknown groups of actinomycetes; actinomycetes of the farmland soil(S8) belonged to three suborders of Micrococcineae, Frankineae and Propionibacterineae as well as the unknown groups of actinomycetes.Phylogenetic analyses of 16 S rRNA gene sequences of actinomycetes from different types of soil samples showed that: actinomycetes of primary saline-alkali soil belonged to seven suborders of Micrococcineae, Propionibacterineae, Corynebacterineae, Frankineae, Pseudonocardineae, Streptomycineae and Streptosporangineae in total as well as the unknown group of actinomycetes; actinomycetes of secondary saline-alkali soil belonged to eight suborders of Micrococcineae, Propionibacterineae, Corynebacterineae, Frankineae, Pseudonocardineae, Streptomycineae, Streptosporangineae and Micromonosporineae in total as well as the unknown group of actinomycetes;actinomyces of farmland soil belonged to four suborders of Micrococcineae, Frankineae, Corynebacterineae and Propionibacterineae as well as the unknown group of actinomycetes.