Cultivation-dependent And Independent Approach To Study Bacterial Diversity Of Four Different Deserts

Life in arid regions and in a particular hot desert is often limited due to their harsh environmental conditions,such as large temperature fluctuations and low amounts of water.These extreme environments can influence the microbial communities present in the desert.In the present study,we have described the bacterial diversity of four different deserts of Cholistan and Thai(Pakistan),Yanbu' al Bahr(Saudi Arabia)and Taklimkan(China).The bacterial diversity of these deserts was investigated by culture dependent method and culture-independent study(metagenomic analysis).In Culture-dependent method 425 bacterial strains were isolated and identified by using the routine laboratory culture method.Among these deserts,the dominant bacteria phyla of Cholistan desert were Actinobacteria with 20 genera(62.5%),followed by Proteobacteria 8 Genera(25%),the others phylum observed in the current observation Firmicutes 2 genera(6.25%),Bacteroidetes I genus(3.125%)and Deinococcus with a single genus(3.125%).The dominant phyla of Thal desert were Actinobecteria and proteobecteria each having 15 genera,while Firmicutes having 4 genera and Bacteroidetes 1 genus.Yanbu' al Bahr desert include 5 different phyla,Actinobacteria having 14 genera(40%),Proteobacteria 12 genera(34.28%),Firmicutes 6 genera(17.14%),Bacteroidetes 2 genera(5.71%)and Deinococcus 1 genus(2.80%).The Thakliman desert sample analysis revealed that this desert was dominated by four Phyla namely,Actinobacteria 9 genera(42.85%),Proteobacteria 9 genera(42.85%),Firmicutes 2 genera(9.5%)and Bacteroidetes 1 genus(4.7%).Culture-independent study(metagenomic analysis)was performed to know about the bacterial diversity of these deserts.We examined twenty four(24)different desert samples,out of which seven samples were selected from the Cholistan,seven from the Thal,seven from the Yanbu' al Bahr,and three from Taklimakan.For determination of bacterial community used pyrosequencing of PCR-amplified V1-V3 regions of 16S rDNA genes from total extracted DNA to reveal and compare the bacterial population diversity of the samples.The results showed a total of 115,725 OTUs in the 24 samples,calculated using ? 97%sequence similarity levels.Total OTUs were 49476 from Cholistan,53155 from thal,11070 from Yanbu' al Bahr and 2024 from Taklimakan were obtained.Chao 1 values ranged 8667-36097(Cholistan),10600-42148(thal),2005-5133(Yanbu' al Bahr)and 1458-1772(Taklimakan).OTUs related to Phylum Proteobacteria,(49.7%),Actinobacteria(18.8%),Firmicutes(8.8%),Chlorfolexi(3.1%),Bacteroidetes(4.2%)as the respective averages for the 24 samples followed by members of the Planctomycetes(3.5%),Deinococuse Thermus(2.1%),Acidobacteria(2.9%)and Gemmatimonadetes(0.6%).Some special bacterial groups such as members of Plantomycests,Actinobacteria,Chloroflexi,Nitrospira,Bacteriods and Gemmatimonadetes,whose population was found significantly correlated to environmental factors in desert soils(pH and concentration of organic matters).This work shows that the Cholistan and That Deserts(Pakistan),Yanbu' al Bahr Desert(Saudi Arabia)and Taklimakan Desert(China)can contain a diverse bacterial community on the sand of desert.Our results indicated that combining different approaches can produce complementary information,thus generate a more accurate view of microbial community in deserts.