ABSTRACT: Temporal shifts of phosphate mobilizing bacterial community reveals contrasting succession patterns in response to different phosphorus sources
Project description:The principles governing acquisition and interspecies exchange of nutrients in microbial communities and how those exchanges impact community productivity are poorly understood. Here, we examine energy and macronutrient acquisition in unicyanobacterial consortia for which species-resolved genome information exists for all members, allowing us to use multi-omic approaches to predict species’ abilities to acquire resources and examine expression of resource-acquisition genes during succession. Metabolic reconstruction indicated that a majority of heterotrophic community members lacked the genes required to directly acquire the inorganic nutrients provided in culture medium, suggesting high metabolic interdependency. The sole primary producer in consortium UCC-O, cyanobacterium Phormidium sp. OSCR, displayed declining expression of energy harvest, carbon fixation, and nitrate and sulfate reduction proteins but sharply increasing phosphate transporter expression over 28 days. Most heterotrophic members likewise exhibited signs of phosphorus starvation during succession. Though similar in their responses to phosphorus limitation, heterotrophs displayed species-specific expression of nitrogen acquisition genes. These results suggest niche partitioning around nitrogen sources may structure the community when organisms directly compete for limited phosphate. Such niche complementarity around nitrogen sources may increase community diversity and productivity in phosphate-limited phototrophic communities.
Project description:Nitrogen (N) and phosphorus (P) are the most limiting factors for plant growth. Some microorganisms improve the uptake and availability of N and P minimizing chemical fertilizers dependence. It has been published that the RD64 strain, a Sinorhizobium meliloti 1021 strain engineered to overproduce indole-3-acetic acid (IAA), showed improved nitrogen fixation ability as compared to the wild type 1021 strain. We present here data showing that RD64 is also highly effective in mobilizing P from insoluble sources such as phosphate rock (PR). Under P-limiting conditions, the higher P-mobilizing activity of RD64, as compared to 1021 wild type strain, is connected with the up-regulation of genes coding for the high-affinity P transport system, the induction of acid phosphatase activity and the increased secretion into the growth media of malic, succinic and fumaric acids. Medicago truncatula plants nodulated by RD64 (Mt-RD64), when grown under P deficient conditions, released higher amounts of another P-solubilizing organic acid, the 2-hydroxyglutaric acid, as compared to the plants nodulated by the wild-type strain (Mt-1021). It has already been shown that Mt-RD64 plants exhibited a higher dry weight production as compared to Mt-1021 plants. Here we report that also P-starved Mt-RD64 plants show a significant increase both in shoot and root fresh weight when compared to P-starved Mt-1021 plants. We discuss how, in a rhizobium-legume model system, a balanced interplay of different factors linked to the bacterial IAA over-production rather than IAA production per se stimulates plant growth under stressful environmental conditions, and in particular, under P-starvation. Two-conditions experiment: untreated 1021 vs. untreated RD64 cells. Biological replicates: 6 untreated control strain, 6 untreated IAA-overproducing strain, independently grown and harvested. One replicate per array.
Project description:Nitrogen (N) and phosphorus (P) are the most limiting factors for plant growth. Some microorganisms improve the uptake and availability of N and P, minimizing chemical fertilizer dependence. It has been published that the RD64 strain, a Sinorhizobium meliloti 1021 strain engineered to overproduce indole-3-acetic acid (IAA), showed improved nitrogen fixation ability as compared to the wild type 1021 strain. We present here data showing that RD64 is also highly effective in mobilizing P from insoluble sources such as phosphate rock (PR). Under P-limiting conditions, the higher P-mobilizing activity of RD64, as compared to the 1021 wild type strain, is connected with the up-regulation of genes coding for the high-affinity P transport system, the induction of acid phosphatase activity and the increased secretion into the growth media of malic, succinic and fumaric acids. Medicago truncatula plants nodulated by RD64 (Mt-RD64), when grown under P-deficient conditions, released higher amounts of another P-solubilizing organic acid, the 2-hydroxyglutaric acid, as compared to the plants nodulated by the wild-type strain (Mt-1021). It has already been shown that Mt-RD64 plants exhibited a higher dry weight production as compared to Mt-1021 plants. Here we report that also P-starved Mt-RD64 plants show a significant increase both in shoot and root fresh weight when compared to P-starved Mt-1021 plants. We discuss how, in a rhizobium-legume model system, a balanced interplay of different factors linked to the bacterial IAA over-production rather than IAA production per se stimulates plant growth under stressful environmental conditions, and in particular, under P-starvation. Two-conditions experiment: untreated vs. IND-treated cells. Biological replicates: 6 untreated control, 6 treated samples, independently grown and harvested. One replicate per array.
Project description:Nitrogen (N) and phosphorus (P) are the most limiting factors for plant growth. Some microorganisms improve the uptake and availability of N and P, minimizing chemical fertilizer dependence. It has been published that the RD64 strain, a Sinorhizobium meliloti 1021 strain engineered to overproduce indole-3-acetic acid (IAA), showed improved nitrogen fixation ability as compared to the wild type 1021 strain. We present here data showing that RD64 is also highly effective in mobilizing P from insoluble sources such as phosphate rock (PR). Under P-limiting conditions, the higher P-mobilizing activity of RD64, as compared to the 1021 wild type strain, is connected with the up-regulation of genes coding for the high-affinity P transport system, the induction of acid phosphatase activity and the increased secretion into the growth media of malic, succinic and fumaric acids. Medicago truncatula plants nodulated by RD64 (Mt-RD64), when grown under P-deficient conditions, released higher amounts of another P-solubilizing organic acid, the 2-hydroxyglutaric acid, as compared to the plants nodulated by the wild-type strain (Mt-1021). It has already been shown that Mt-RD64 plants exhibited a higher dry weight production as compared to Mt-1021 plants. Here we report that also P-starved Mt-RD64 plants show a significant increase both in shoot and root fresh weight when compared to P-starved Mt-1021 plants. We discuss how, in a rhizobium-legume model system, a balanced interplay of different factors linked to the bacterial IAA over-production rather than IAA production per se stimulates plant growth under stressful environmental conditions, and in particular, under P-starvation. Two-conditions experiment: untreated 1021 vs. ICA-treated 1021 cells. Biological replicates: 6 untreated control, 6 treated samples, independently grown and harvested. One replicate per array.
Project description:Nitrogen (N) and phosphorus (P) are the most limiting factors for plant growth. Some microorganisms improve the uptake and availability of N and P, minimizing chemical fertilizer dependence. It has been published that the RD64 strain, a Sinorhizobium meliloti 1021 strain engineered to overproduce indole-3-acetic acid (IAA), showed improved nitrogen fixation ability as compared to the wild type 1021 strain. We present here data showing that RD64 is also highly effective in mobilizing P from insoluble sources such as phosphate rock (PR). Under P-limiting conditions, the higher P-mobilizing activity of RD64, as compared to the 1021 wild type strain, is connected with the up-regulation of genes coding for the high-affinity P transport system, the induction of acid phosphatase activity and the increased secretion into the growth media of malic, succinic and fumaric acids. Medicago truncatula plants nodulated by RD64 (Mt-RD64), when grown under P-deficient conditions, released higher amounts of another P-solubilizing organic acid, the 2-hydroxyglutaric acid, as compared to the plants nodulated by the wild-type strain (Mt-1021). It has already been shown that Mt-RD64 plants exhibited a higher dry weight production as compared to Mt-1021 plants. Here we report that also P-starved Mt-RD64 plants show a significant increase both in shoot and root fresh weight when compared to P-starved Mt-1021 plants. We discuss how, in a rhizobium-legume model system, a balanced interplay of different factors linked to the bacterial IAA over-production rather than IAA production per se stimulates plant growth under stressful environmental conditions, and in particular, under P-starvation. Two-conditions experiment: untreated vs. Trp-treated cells. Biological replicates: 6 untreated control, 6 treated samples, independently grown and harvested. One replicate per array.
Project description:Nitrogen (N) and phosphorus (P) are the most limiting factors for plant growth. Some microorganisms improve the uptake and availability of N and P, minimizing chemical fertilizer dependence. It has been published that the RD64 strain, a Sinorhizobium meliloti 1021 strain engineered to overproduce indole-3-acetic acid (IAA), showed improved nitrogen fixation ability as compared to the wild type 1021 strain. We present here data showing that RD64 is also highly effective in mobilizing P from insoluble sources such as phosphate rock (PR). Under P-limiting conditions, the higher P-mobilizing activity of RD64, as compared to the 1021 wild type strain, is connected with the up-regulation of genes coding for the high-affinity P transport system, the induction of acid phosphatase activity and the increased secretion into the growth media of malic, succinic and fumaric acids. Medicago truncatula plants nodulated by RD64 (Mt-RD64), when grown under P-deficient conditions, released higher amounts of another P-solubilizing organic acid, the 2-hydroxyglutaric acid, as compared to the plants nodulated by the wild-type strain (Mt-1021). It has already been shown that Mt-RD64 plants exhibited a higher dry weight production as compared to Mt-1021 plants. Here we report that also P-starved Mt-RD64 plants show a significant increase both in shoot and root fresh weight when compared to P-starved Mt-1021 plants. We discuss how, in a rhizobium-legume model system, a balanced interplay of different factors linked to the bacterial IAA over-production rather than IAA production per se stimulates plant growth under stressful environmental conditions, and in particular, under P-starvation. Two-conditions experiment: untreated 1021 vs. IAA-treated 1021 cells. Biological replicates: 6 untreated controls, 6 treated samples, independently grown and harvested. One replicate per array.
Project description:Nitrogen (N) and phosphorus (P) are the most limiting factors for plant growth. Some microorganisms improve the uptake and availability of N and P, minimizing chemical fertilizer dependence. It has been published that the RD64 strain, a Sinorhizobium meliloti 1021 strain engineered to overproduce indole-3-acetic acid (IAA), showed improved nitrogen fixation ability as compared to the wild type 1021 strain. We present here data showing that RD64 is also highly effective in mobilizing P from insoluble sources such as phosphate rock (PR). Under P-limiting conditions, the higher P-mobilizing activity of RD64, as compared to the 1021 wild type strain, is connected with the up-regulation of genes coding for the high-affinity P transport system, the induction of acid phosphatase activity and the increased secretion into the growth media of malic, succinic and fumaric acids. Medicago truncatula plants nodulated by RD64 (Mt-RD64), when grown under P-deficient conditions, released higher amounts of another P-solubilizing organic acid, the 2-hydroxyglutaric acid, as compared to the plants nodulated by the wild-type strain (Mt-1021). It has already been shown that Mt-RD64 plants exhibited a higher dry weight production as compared to Mt-1021 plants. Here we report that also P-starved Mt-RD64 plants show a significant increase both in shoot and root fresh weight when compared to P-starved Mt-1021 plants. We discuss how, in a rhizobium-legume model system, a balanced interplay of different factors linked to the bacterial IAA over-production rather than IAA production per se stimulates plant growth under stressful environmental conditions, and in particular, under P-starvation. Two-conditions experiment: untreated 1021 vs. 2,4-D-treated 1021 cells. Biological replicates: 6 untreated controls, 6 treated samples, independently grown and harvested. One replicate per array.
Project description:The Chlamydomonas reinhardtii transcription factor PSR1 is required for the control of activities involved in scavenging phosphate from the environment during periods of phosphorus limitation. Increased scavenging activity reflects the development of high-affinity phosphate transport and the expression of extracellular phosphatases that can cleave phosphate from organic compounds in the environment. A comparison of gene expression patterns using microarray analyses and quantitative PCRs with wild-type and psr1 mutant cells deprived of phosphorus has revealed that PSR1 also controls genes encoding proteins with potential "electron valve" functions--these proteins can serve as alternative electron acceptors that help prevent photodamage caused by overexcitation of the photosynthetic electron transport system. In accordance with this finding, phosphorus-starved psr1 mutants die when subjected to elevated light intensities; at these intensities, the wild-type cells still exhibit rapid growth. Acclimation to phosphorus deprivation also involves a reduction in the levels of transcripts encoding proteins involved in photosynthesis and both cytoplasmic and chloroplast translation as well as an increase in the levels of transcripts encoding stress-associated chaperones and proteases. Surprisingly, phosphorus-deficient psr1 cells (but not wild-type cells) also display expression patterns associated with specific responses to sulfur deprivation, suggesting a hitherto unsuspected link between the signal transduction pathways involved in controlling phosphorus and sulfur starvation responses. Together, these results demonstrate that PSR1 is critical for the survival of cells under conditions of suboptimal phosphorus availability and that it plays a key role in controlling both scavenging responses and the ability of the cell to manage excess absorbed excitation energy. Set of arrays that are part of repeated experiments Keywords: Biological Replicate