ABSTRACT
A Gram-negative, aerobic, nonmotile, rod-shaped and yellow-pigment-producing bacteria was isolated from Baima snow mountain of Diqing Tibetan Autonomous Prefecture in Yunnan province, south-west China and characterized using a polyphasic approach. The results of 16S rRNA gene sequence similarity analysis showed that strain YIM B04101T was closely related to the type strain of Dyadobacter koreensis DSM 19938T (97.81%) and Dyadobacter frigoris AR-3-8T (97.95%). The predominant respiratory quinone was menaquinone-7 (MK-7). The major polar lipid was phosphatidylethanolamine. The major fatty acids were summed feature 3 (C16:1ω7c/C16:1ω6c), C18:1ω9c and C16:0. The DNA G + C content was 43.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the strain YIM B04101T belonged to a cluster comprising species of the genus Dyadobacter. However, it differed from its closest relative, Dyadobacter koreensis KCTC 12537T and Dyadobacter frigoris AR-3-8T, in many physiological properties. Based on these phenotypic characteristics and phylogenetic distinctiveness, strain YIM B04101T is considered to be a novel species of the genus Dyadobacter, for which the name Dyadobacter diqingensis sp. nov. is proposed. The type strain is YIM B04101T (= CGMCC 1.19249T = CCTCC AB 2021270).
Subject(s)
Fatty Acids , Snow , Bacterial Typing Techniques , China , Cytophagaceae , DNA, Bacterial/genetics , Fatty Acids/analysis , Phospholipids , Phylogeny , RNA, Ribosomal, 16S/genetics , Sequence Analysis, DNA , TibetABSTRACT
Ectomycorrhizal (EcM) fungi play important roles in forest ecosystems, and their richness and composition can change along with elevation and season changes. However, no study has estimated the relative importance of altitudinal and seasonal heterogeneity in predicting the distribution of EcM fungal communities by simultaneously considering different sample types (root versus soil). In this study, we collected root and soil samples along a > 1,500-m elevation gradient during wet and dry seasons from Baima Snow Mountain, located in "the Mountains of Southwest China," one of the 34 biodiversity hot spots, and we analyzed them using next-generation sequencing. Regardless of the sample type, similar EcM fungal richness pattern with increasing elevation (decline in the forest zone, and an increase at the alpine meadow zone) and strong community turnovers among different elevational zones and between two seasons were detected, and changes of EcM fungal community similarity on 400-m altitude gradient were equivalent to the community turnover between dry and wet seasons. Elevation and edaphic factors were shown to have the largest effects on EcM fungal community. The heterogeneity of richness and community composition was stronger among different elevational zones than across different seasons, mainly because the elevation variations in the EcM fungal community were shaped by the combined effects of different environmental factors, while seasonal changes were mainly controlled by temperature and fast-changing soil nutrients. IMPORTANCE Altitude and season represent two important environmental gradients that shape the structure of biome, including the heterogeneity of EcM fungi. Previous studies have separately considered the influences of altitude and season on EcM fungal communities, but the relative importance of altitude and season is still unknown. The present study revealed that elevation influences the heterogeneity of EcM fungal community more than season; this may be because the variability of environmental factors is higher across different elevations than that across seasons.