Project description:Global warming has shifted climate zones poleward or upward. However, understanding the responses and mechanism of microbial community structure and functions relevant to natural climate zone succession is challenged by the high complexity of microbial communities. Here, we examined soil microbial community in three broadleaved forests located in the Wulu Mountain (WLM, temperate climate), Funiu Mountain (FNM, at the border of temperate and subtropical climate zones), or Shennongjia Mountain (SNJ, subtropical climate).Soils were characterized for geochemistry, Illumina sequencing was used to determine microbial taxonomic communities and GeoChips 5.0 were used to determine microbial functional genes.
Project description:Despite the global importance of forests, it is virtually unknown how their soil microbial communities adapt at the phylogenetic and functional level to long term metal pollution. Studying twelve sites located along two distinct gradients of metal pollution in Southern Poland revealed that both community composition (via MiSeq Illumina sequencing of 16S rRNA genes) and functional gene potential (using GeoChip 4.2) were highly similar across the gradients despite drastically diverging metal contamination levels. Metal pollution level significantly impacted microbial community structure (p = 0.037), but not bacterial taxon richness. Metal pollution altered the relative abundance of specific bacterial taxa, including Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Firmicutes, Planctomycetes and Proteobacteria. Also, a group of metal resistance genes showed significant correlations with metal concentrations in soil, although no clear impact of metal pollution levels on overall functional diversity and structure of microbial communities was observed. While screens of phylogenetic marker genes, such as 16S rRNA, provided only limited insight into resilience mechanisms, analysis of specific functional genes, e.g. involved in metal resistance, appeared to be a more promising strategy. This study showed that the effect of metal pollution on soil microbial communities was not straightforward, but could be filtered out from natural variation and habitat factors by multivariate statistical analysis and spatial sampling involving separate pollution gradients.
2014-07-22 | GSE59620 | GEO
Project description:Soil bacteria under deadwood in forests
Project description:A comparision of soil microbial functional genes of three types of subtropical broad-leaved forests Microbial functional structure was significantly different among SBFs (P < 0.05). Compared to the DBF and the EBF, the MBF had higher alpha-diversity of functional genes but lower beta-diversity, and showed more complex functional gene networks.
Project description:Drought-responsive genes in soybean leaves were successfully identified using Affymetrix Soybean Gene 1.0 ST arrays on leaves samples of reproductive-stage soybean plants. R1 soybean plants planted in pots were imposed drought by withholding water for 5 days until the soil moisture content dropped to 5%, and 3rd trifoliates (now at the R2 stage) were collected for expression profiling.
Project description:Here we have compared adult wildtype (N2) C. elegans gene expression when grown on different bacterial environments/fod sources in an effort to model naturally occuring nematode-bacteria interactions at the Konza Prairie. We hypothesize that human-induced changes to natural environments, such as the addition of nitrogen fertalizer, have effects on the bacterial community in soils and this drives downstream changes in the structure on soil bacterial-feeding nematode community structure. Here we have used transcriptional profiling to identify candidate genes involved in the interaction of nematodes and bacteria in nature.
Project description:The response to moderate and heavy drought of two Solanum tuberosum ssp. Andigena varieties, Sullu (NP 03.03) and SA 2563 (NP 03.01), planted in rain- and soil water protected fields in the Peruvian highlands are compared. Previous experiments indicate that Sullu has a greater capacity for yield maintenance under drought than SA 2563. Both clones have similar morphological properties, vegetative periods and rooting depths, so it can be assumed that the cause for increased drought tolerance of clone NP 03.03 is rather due to physiological or biochemical mechanisms, than to drought escape by deep rooting or earliness. Sullu and SA 2563 were planted in a random block design with 5 plants per bloc and 7 repetitions per treatment. Treatments: (1) drought stress, (2) irrigated control The plants were drip-irrigated in both treatments until tuberization (until day 84 after planting). Subsequently, the irrigation was stopped in the drought field, but continued in the control field. The soil moisture content in the control field was kept near field capacity. Planting date: October 05 2004 Start of drought treatment (during tuberization, 84 days after planting): December 28 2004 First sampling (soil water potential: -0.3 mPa 114 days after planting): January 27 2005 Second sampling (soil water potential –0.6 MPa, 134 days after planting): February 15 2005 Harvest: March 19 2005 (165 days after planting) The experimental design includes gene expression analysis in leaves, roots and stolons at two time points, when soil water potential reaches -0.3 and –0.6 MPa. Gene expression changes will be set in relation with physiological and agronomical data obtained in the same experiment. Keywords: Direct comparison