Project description:Gene expression profiling in soybean under aluminum stress: mechanisms of magnesium amelioration of aluminum toxicity at gene expression level. Micro-molar concentrations of magnesium in culture solution has been shown to ameliorate Al toxicity in soybean and other leguminous species. Different theories have been proposed to explain the chemical mechanisms of how the two ions interact to neutralize the toxic effect of aluminum in the plant root system. To understand the molecular mechanisms of the phenomenon at the gene expression level in soybean, we undertook a comparative transcriptome analysis in Al-tolerant and Al-sensitive genotypes treated with aluminum alone or aluminum plus magnesium using DNA microarrays. The results revealed magnesium enhances Al-tolerance level in the Al-tolerant genotype by down-regulating genes commonly induced in response to Al toxicity. We hypothesized that the magnesium-mediated alleviation of Al toxicity in the Al-tolerant genotype emanates from reduction in energy expenditure of gene expression induced in response to Al stress. Conversely, magnesium appears to ameliorate Al toxicity in the sensitive genotype by dual mechanisms of increasing the expression level of several genes involved in Al-tolerance and decreasing the expression level of most genes. Keywords: Soybean, aluminum toxicity, magnesium, transcriptome Two genotypes: PI 416937 (p) and Young (y); two treatments: Aluminum (Al) or Al+magnesium (Mg); two time points: 12 and 72 hrs; 3 replicates.
Project description:Gene expression profiling in soybean under aluminum stress: Transcriptome response to Al stress in roots of Al-tolerant genotype (PI 416937). Aluminum (Al) toxicity is a major constraint of crop production on acid soils. Many commercial soybean cultivars and advanced breeding lines have been evaluated for Al tolerance. Aluminum tolerance is quantitatively inherited trait in soybean making it difficult for genetic improvement. Understanding the molecular and genetic mechanisms of tolerance is crucial for developing efficient and effective programs aimed at improving Al tolerance trait The molecular mechanisms of Al tolerance is poorly understood in soybean. The objective of the research was to identify candidate aluminum tolerance genes in soybean Al-tolerant soybean genotype PI 416937 seedlings were exposed to zero or 10 µM Al in growth chamber under hydroponic conditions for four time span of 2, 12, 48 and 72 hrs in a randomized complete block design with three replications. Microarray analysis was made on mRNA isolated from 1 cm log tap root tips using Affymetrix soybean array with over 68,000 probe sets Glycine max L and wild soybean combined. Both novel and known genes were discovered in response to Al treatment. They include Al tolerance relevant proteins, families of transcription factors, zinc finger, bZIP, WRKY, MYB, ADR6, and NAC domain proteins were induced likely regulating Al tolerance downstream genes. Stress related proteins, cytochrome P450, glutathione-s transferase, glutaredoxin family and ascorbic acid biosynthesis protein were induced as signatures of cellular detoxification mechanisms. An ABC type multidrug resistance protein that could act as citrate transporter or Al exporter was up-regulated, a key Al tolerance mechanisms in several species. A cell wall loosening enzyme endoxylglucan hydrolases were also up-regulated probably reversing the wall rigidification caused by Al and promoting root growth under Al stress. Phytosulfokines growth factor involved in cell division and proliferation was up-regulated likely as a direct counter action to Al toxicity which inhibits root growth by limiting cell division and elongation. In conclusion, the Al tolerance candidate genes identified herein are potential targets for future genetic engineering and molecular breeding work on Al tolerance trait in soybean which in turn would contribute to gain in soybean productivity on acid soils.
Project description:Gene expression profiling in soybean under aluminum stress: Transcriptome response to Al stress in roots of Al-tolerant genotype (PI 416937). Aluminum (Al) toxicity is a major constraint of crop production on acid soils. Many commercial soybean cultivars and advanced breeding lines have been evaluated for Al tolerance. Aluminum tolerance is quantitatively inherited trait in soybean making it difficult for genetic improvement. Understanding the molecular and genetic mechanisms of tolerance is crucial for developing efficient and effective programs aimed at improving Al tolerance trait The molecular mechanisms of Al tolerance is poorly understood in soybean. The objective of the research was to identify candidate aluminum tolerance genes in soybean Al-tolerant soybean genotype PI 416937 seedlings were exposed to zero or 10 µM Al in growth chamber under hydroponic conditions for four time span of 2, 12, 48 and 72 hrs in a randomized complete block design with three replications. Microarray analysis was made on mRNA isolated from 1 cm log tap root tips using Affymetrix soybean array with over 68,000 probe sets Glycine max L and wild soybean combined. Both novel and known genes were discovered in response to Al treatment. They include Al tolerance relevant proteins, families of transcription factors, zinc finger, bZIP, WRKY, MYB, ADR6, and NAC domain proteins were induced likely regulating Al tolerance downstream genes. Stress related proteins, cytochrome P450, glutathione-s transferase, glutaredoxin family and ascorbic acid biosynthesis protein were induced as signatures of cellular detoxification mechanisms. An ABC type multidrug resistance protein that could act as citrate transporter or Al exporter was up-regulated, a key Al tolerance mechanisms in several species. A cell wall loosening enzyme endoxylglucan hydrolases were also up-regulated probably reversing the wall rigidification caused by Al and promoting root growth under Al stress. Phytosulfokines growth factor involved in cell division and proliferation was up-regulated likely as a direct counter action to Al toxicity which inhibits root growth by limiting cell division and elongation. In conclusion, the Al tolerance candidate genes identified herein are potential targets for future genetic engineering and molecular breeding work on Al tolerance trait in soybean which in turn would contribute to gain in soybean productivity on acid soils. One genotype PI 416937 (p); four time points: (2, 12, 48, and 72 hrs), with replicates (2 or 3)
Project description:Gene expression profiling in soybean under aluminum stress: mechanisms of magnesium amelioration of aluminum toxicity at gene expression level. Micro-molar concentrations of magnesium in culture solution has been shown to ameliorate Al toxicity in soybean and other leguminous species. Different theories have been proposed to explain the chemical mechanisms of how the two ions interact to neutralize the toxic effect of aluminum in the plant root system. To understand the molecular mechanisms of the phenomenon at the gene expression level in soybean, we undertook a comparative transcriptome analysis in Al-tolerant and Al-sensitive genotypes treated with aluminum alone or aluminum plus magnesium using DNA microarrays. The results revealed magnesium enhances Al-tolerance level in the Al-tolerant genotype by down-regulating genes commonly induced in response to Al toxicity. We hypothesized that the magnesium-mediated alleviation of Al toxicity in the Al-tolerant genotype emanates from reduction in energy expenditure of gene expression induced in response to Al stress. Conversely, magnesium appears to ameliorate Al toxicity in the sensitive genotype by dual mechanisms of increasing the expression level of several genes involved in Al-tolerance and decreasing the expression level of most genes. Keywords: Soybean, aluminum toxicity, magnesium, transcriptome
Project description:Gene expression profiling in soybean under aluminum stress: genes differentially expressed between Al-tolerant and Al-sensitive genotypes. Aluminum toxicity is the most important constraint of crop production on acid soils. Understanding the molecular and genetic mechanisms of tolerance is crucial for developing efficient breeding programs to improve Al tolerance. This research was undertaken to identify candidate Al-tolerance genes in soybean. Two soybean genotypes PI 416937 (Al-tolerant) and Young (Al-sensitive) seedlings were exposed to zero or 10 µM Al in a growth chamber under hydroponic conditions for four time spans of 2, 12, 48 or 72 hrs. Microarray analysis was made on mRNA isolated from 1 cm long tap root tips using an Affymetrix soybean genome array. Both novel and previously reported aluminum-responsive genes were identified. The differentially expressed genes were enriched for metabolism, stress response and transporters. Multiple putative Al-tolerance genes uniquely induced in the tolerant genotype includes the up-regulation of previously identified transcription factors auxin down regulated-like protein (ADR6-like) and basic leucine zipper (bZIP 94), sulfur transmembrane transport protein and lipid transfer protein (Sec 14 ) and novel genes that include rare cold inducible protein (RCI2B ), GPI-transamidase, malonyl-COA: Isoflavone 7-O-glucoside-6˝-O-malontransferase, a cell proliferation protein (WPP2), Oleosin protein, pectinestrease inhibitor, and impaired sucrose induction1. The genes identified in this study will be utilized as important genetic resources for future improvement of Al tolerance in soybean. Key words: Soybean, Al tolerance, gene expression, microarray Two genotypes: PI 416937 (p) and Young (y); two treatments: aluminum or untreated; four time points: 2, 12, 48, and 72 hrs; 2 or 3 replicates.
Project description:Gene expression profiling in soybean under aluminum stress: genes differentially expressed between Al-tolerant and Al-sensitive genotypes. Aluminum toxicity is the most important constraint of crop production on acid soils. Understanding the molecular and genetic mechanisms of tolerance is crucial for developing efficient breeding programs to improve Al tolerance. This research was undertaken to identify candidate Al-tolerance genes in soybean. Two soybean genotypes PI 416937 (Al-tolerant) and Young (Al-sensitive) seedlings were exposed to zero or 10 µM Al in a growth chamber under hydroponic conditions for four time spans of 2, 12, 48 or 72 hrs. Microarray analysis was made on mRNA isolated from 1 cm long tap root tips using an Affymetrix soybean genome array. Both novel and previously reported aluminum-responsive genes were identified. The differentially expressed genes were enriched for metabolism, stress response and transporters. Multiple putative Al-tolerance genes uniquely induced in the tolerant genotype includes the up-regulation of previously identified transcription factors auxin down regulated-like protein (ADR6-like) and basic leucine zipper (bZIP 94), sulfur transmembrane transport protein and lipid transfer protein (Sec 14 ) and novel genes that include rare cold inducible protein (RCI2B ), GPI-transamidase, malonyl-COA: Isoflavone 7-O-glucoside-6˝-O-malontransferase, a cell proliferation protein (WPP2), Oleosin protein, pectinestrease inhibitor, and impaired sucrose induction1. The genes identified in this study will be utilized as important genetic resources for future improvement of Al tolerance in soybean. Key words: Soybean, Al tolerance, gene expression, microarray
Project description:We conducted a genome-wide transcriptomic analysis in soybean leaves treated with a short-term (24 h) Pi-deficiency using RNA sequencing (RNA-seq) technology. Two biological replicates of RNA-seq were included for both Pi-sufficient leaves (PSL) and Pi-deficient leaves (PDL), and therefore a total of four libraries were constructed. Using a 2-fold change and a P-value ≤0.05 as the cut-off for selecting the differentially expressed transcripts, we globally identified short-term Pi-stress responsive genes. Some DEGs potentially involved in Pi sensing, signaling, and homeostasis were up-regulated by Pi deprivation, including five SPX-containing genes. Some DEGs possibly associated with water and nutrient uptake, hormonal and calcium signaling, protein phosphorylation and dephosphorylation, and cell wall modification were affected at the early stage of Pi deprivation. At least thirty-one transcription factor genes belonging to 10 diverse families were found to be responsive to Pi starvation.
Project description:Aluminum (Al) toxicity is a major factor limiting crop yields on acid soils. In maize, Al tolerance is a complex phenomenon involving multiple genes and physiological mechanisms yet uncharacterized. To begin elucidating the molecular basis of maize Al toxicity and tolerance, we performed a detailed temporal analysis of root gene expression under Al stress using microarrays with an Al-tolerant and an Al-sensitive maize genotype. Seedlings of both genotypes were grown in hydroponics in a full nutrient solution containing 39uM of free Al3+ activity. Root samples were collected at 'time zero', and after 2, 6 and 24 hours of treatment. Keywords: stress treatment, time course