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Understanding the distribution and abundance of microbial stress-related genes (SRGs) is crucial for unraveling the intricate dynamics of microbial communities and their responses to diverse environmental conditions. Despite the importance of these genes in shaping microbial adaptation and resilience, a comprehensive examination of their relative abundance across distinct climatic regions, such as boreal, temperate, and tropical environments, remains notably scarce in the existing literature. This study seeks to address this research gap by exploring and comparing the relative abundances of microbial SRGs using GeoChip 5.0 functional gene array in these three climatic regions. Our data indicate a greater relative abundance of SRGs such as nsrR , degP , cpxR, ahpF , Obg and cisD in the tropical region than in the other two regions whereas ecf and glnA showed higher abundance in both temperate and tropical regions in terms of reference forests and old parks. The distinct characteristics of the tropical biome are likely to influence both SRGs and the profile of SRG-hosts, consequently enhancing soil microbial abundances. Moreover, multivariate analyses unveiled distinct SRG profiles in urban parks and climatic regions. Additionally, we explored the influence of plant functional types (recalcitrant and labile tree litter, lawn) on SRGs. The impact of vegetation type on SRGs was not statistically significant, except in the tropical region, where its influence was notably pronounced compared to the boreal and temperate regions. Furthermore, several genes (nsrR , degP , cpxR , degS , dnaK , Obg , cisD , and glnA) were more prevalent in old parks when compared to young parks in all three climatic regions. However, urban parks displayed a significantly elevated abundance of SRGs compared to forest areas. This study provides new insights into the prevalence of SRGs across different climatic regions, enhancing our understanding of their dynamics in both human-influenced environments and pristine habitats. [Display omitted] [ABSTRACT FROM AUTHOR]

Anthropogenic activities have led to serious contamination of halogenated organic pollutants (HOPs), such as PCBs, PBDEs, and HBCDs, in the mangrove wetland. Biodegradation of HOPs is generally driven by environmental microorganisms harboring dehalogenase genes. However, little is known if HOPs can affect the distributions of HOPs-degrading bacteria and dehalogenase genes in the mangrove wetlands. Historical data suggested that HOPs contamination has been persistent and even deteriorated in the mangrove wetlands in China. We found that the organohalides-respiring bacteria Dehalococcoidia and reductive dehalogenase genes were more prevalent in the subsurface layer sediments (20-30 cm depth; 1.935-9.876 % relative abundance; 71-286 contigs) than the surface layer (0-5 cm depth; 0.174-2.020 % relative abundance; 7-130 contigs). While the genes of haloacid and haloalkane dehalogenases were more abundant in the surface layer (30-100 and 18-138 contigs) than the subsurface layer (22-56 and 50-101 contigs). The abundance of HOPs-degrading genes of reductive dehalogenase, haloacid dehalogenases, AtzA, AtzB, TrzA, TrzN, PcpB, were determined by GeoChip 5.0. Their total abundance ranged from 444.760 to 880.909. Their distributions were mainly associated with the contamination levels of HOPs and strength of anthropogenic activities around the mangrove wetlands. Therefore, the distribution of bacterial taxa and genes involved in HOPs degradation was related to the depth of sediments and affected by the selective stress from HOPs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025. Published by Elsevier B.V.)