Project description:The purpose of the present study is to determine the effect of Phosphorus deficiency on gene expression level using microarray analysis to identify genes responsible for root hair development. Phosphorus deficiency induced the formation of root hairs to explore a greater soil volume but molecular mechanisms were unknown. Therefore, microarray experiments were performed using root tips of Brassica carinata cultivars Bale and Bacho, respectively differing in root hair length during Phosphorus deficiency. Experimental design was carried out in nutrient solution in a climate chamber with controlled environmental conditions (20°C, 16h day/8h night cycle, 70% relative humidity) in a randomized design. 25 root tips from 10 day old seedlings grown without Phosphorus of 1cm length were harvested and immediately frozen in liquid nitrogen. Gene expression analyses were performed
Project description:The purpose of the present study is to determine the effect of Phosphorus deficiency on gene expression level using microarray analysis to identify genes responsible for root hair development. Phosphorus deficiency induced the formation of root hairs to explore a greater soil volume but molecular mechanisms were unknown. Therefore, microarray experiments were performed using root tips of Brassica carinata cultivars Bale and Bacho, respectively differing in root hair length during Phosphorus deficiency. Experimental design was carried out in nutrient solution in a climate chamber with controlled environmental conditions (20°C, 16h day/8h night cycle, 70% relative humidity) in a randomized design. 25 root tips from 10 day old seedlings grown without Phosphorus of 1cm length were harvested and immediately frozen in liquid nitrogen. Gene expression analyses were performed Results from xy microarrays are summarized in this study. The samples originate from roots of cultivars Bale and Bacho grown in Phosphorus deficient conditions. Microarrays were hybridized with Cy3 and Cy5 labeled cDNA from Bale and Bacho both during Phosphorus deficiency using a dye swap approach
Project description:Because of severe abiotic limitations, Antarctic soils represent simplified ecosystems, where microorganisms are the principle drivers of nutrient cycling. This relative simplicity makes these ecosystems particularly vulnerable to perturbations, like global warming, and the Antarctic Peninsula is among the most rapidly warming regions on the planet. However, the consequences of the ongoing warming of Antarctica on microorganisms and the processes they mediate are unknown. Here, using 16S rRNA gene pyrosequencing and qPCR, we report a number of highly consistent changes in microbial community structure and abundance across very disparate sub-Antarctic and Antarctic environments following three years of experimental field warming (+ 0.5-2°C). Specifically, we found significant increases in the abundance of fungi and bacteria and in the Alphaproteobacteria-to-Acidobacteria ratio. These alterations were linked to a significant increase in soil respiration. Furthermore, the shifts toward generalist or opportunistic bacterial communities following warming weakened the linkage between bacterial diversity and functional diversity. Warming also increased the abundance of some organisms related to the N-cycle, detected as an increase in the relative abundance of nitrogenase genes via GeoChip microarray analyses. Our results demonstrate that soil microorganisms across a range of sub-Antarctic and Antarctic environments can respond consistently and rapidly to increasing temperatures, thereby potentially disrupting soil functioning.
Project description:Because of severe abiotic limitations, Antarctic soils represent simplified ecosystems, where microorganisms are the principle drivers of nutrient cycling. This relative simplicity makes these ecosystems particularly vulnerable to perturbations, like global warming, and the Antarctic Peninsula is among the most rapidly warming regions on the planet. However, the consequences of the ongoing warming of Antarctica on microorganisms and the processes they mediate are unknown. Here, using 16S rRNA gene pyrosequencing and qPCR, we report a number of highly consistent changes in microbial community structure and abundance across very disparate sub-Antarctic and Antarctic environments following three years of experimental field warming (+ 0.5-2°C). Specifically, we found significant increases in the abundance of fungi and bacteria and in the Alphaproteobacteria-to-Acidobacteria ratio. These alterations were linked to a significant increase in soil respiration. Furthermore, the shifts toward generalist or opportunistic bacterial communities following warming weakened the linkage between bacterial diversity and functional diversity. Warming also increased the abundance of some organisms related to the N-cycle, detected as an increase in the relative abundance of nitrogenase genes via GeoChip microarray analyses. Our results demonstrate that soil microorganisms across a range of sub-Antarctic and Antarctic environments can respond consistently and rapidly to increasing temperatures, thereby potentially disrupting soil functioning. We conducted in situ warming experiments for three years using open-top chambers (OTCs) at one sub-Antarctic (Falkland Islands, 52ºS) and two Antarctic locations (Signy and Anchorage Islands, 60ºS and 67ºS respectively) (see Supplementary Fig. 1 for a map). OTCs increased annual soil temperature by an average of 0.8°C (at a depth of 5 cm), resulting in 8-43% increase in positive-degree days annually and a decrease in freeze-thaw cycle frequency by an average of 15 cycles per year (8). At each location, we included densely vegetated and bare fell-field soils in the experimental design for a total of six environments. Densely vegetated and bare environments represent two contrasting environments for Antarctic soil microorganisms, with large differences in terms of C and N inputs to soils. Massively parallel pyrosequencing (Roche 454 GS FLX Titanium) of 16S rRNA gene amplicons was used to follow bacterial diversity and community composition [GenBank Accession Numbers: HM641909-HM744649], and functional gene microarrays (GeoChip 2.0)(11) were used to assess changes in functional gene distribution. Bacterial and fungal communities were also quantified using real-time PCR.
Project description:The oxalate-carbonate Pathway (OCP) refers to the biotransformation process of soil Oxalate degradation and coupled Carbonate formation. It is of great significance to explore this complex biotransformation process to improve the suitable rhizosphere environment and promote soil carbon cycle. A strain of oxalate degrading bacteria, Spirillum OX-1, was isolated from soil.
Project description:Nipponbare performs poorly in phosphorus (P) deficient soil whereas a Nipponbare-derived NIL containing the Pup1 allele of donor parent Kasalath is tolerant to P deficiency. In this experiment we compared gene expression patterns in roots of this NIL to Nipponbare, grown either in a P deficient or P fertilized soil. The aim is to separate constitutive differences in expression from those induced by P deficiency. Keywords: genotype comparison, constitutive differential expression
Project description:The aim of this study was to identify eQTL in Brassica rapa grown under altered soil phosphorus (P) supply, to understand better the genetic architecture of P-use efficiency (PUE) in plants. Recombinant inbred lines (RILs) of the BraIRRI mapping population were grown at adequate and growth-limiting soil P. Variation in leaf gene expression was quantified using an Agilent Brassica 95k oligonucleotide array. Informative gene expression markers (GEMs) were used to map eQTL and PUE-related QTL. Gene expression was highly dependent on soil P supply. However, the altered expression of many genes, including known P-responsive genes, was highly heritable. Interval mapping using P supply as a covariate revealed 18,876 eQTL, representing 15,912 unique probes. Notable trans-eQTL hotspots occurred on chromosomes A06 and A01; these were enriched with protein modification and phosphorus metabolism-related (A06), as well as chloroplast and photosynthesis-related (A01) transcripts. Regulatory loci and genes associated with P-use efficiency identified through eQTL analysis are potential targets for further characterisation and may have potential for crop improvement. Availability of the annotated B. rapa genome sequence will facilitate their study, including the separation of cis- and trans- effects.
2011-06-29 | GSE27052 | GEO
Project description:Effects of Chlortetracycline Addition on Phosphorus Transformation and Availability Mediated by Phosphorus Cycling Microorganisms in Organic Fertilized Soil
Project description:protein based stable isotope probing was performed for identifying microorganisms actually responsible for biphenyl biodegradation in soil environment.