Project description:Proton toxicity is one of the major environmental stresses limiting crop production, and becomes increasingly serious because of anthropogenic activities. To understand acid tolerance mechanisms, the plant growth, mineral nutrient accumulation and global transcriptome changes in soybean (Glycine max) in response to long-term acid stress were investigated. Results showed that acid stress significantly inhibited soybean root growth, but exhibited slight effects on the shoot growth. Moreover, concentrations of essential mineral nutrients were significantly affected by acid stress, mainly dependent on soybean organs and mineral nutrient types. The concentrations of phosphorus (P) and molybdenum (Mo) in both leaves and roots, nitrogen (N) and potassium (K) in roots and magnesium (Mg) in leaves were significantly decreased, respectively. Whereas, the concentrations of calcium (Ca), sulfate (S) and iron (Fe) were increased in both leaves and roots. Transcriptome analyses in soybean roots resulted in identifying 419 up-regulated and 555 down-regulated genes under acid conditions. A total of 38 differentially expressed genes (DEGs) were involved in mineral nutrient transportation. Among them, all the detected five GmPTs and GmZIPs, two GmAMTs and GmKUP genes, together with GmIRT1, GmNramp5, GmVIT2.1, GmSKOR, GmTPK5 and GmHKT1, were significantly suppressed. Moreover, the genes encoding transcription factors (e.g., GmSTOP2s and a GmPHL1), and genes involved in pH stat metabolic pathways were significantly up-regulated by low pH stress in soybean roots. Taken together, it strongly suggested that maintaining pH stat and mineral nutrient homeostasis are adaptive strategies of soybean responses to acid stress, which might be regulated by a complex signaling network.
Project description:Roots are generally the critical drought sensors, but little is known about their molecular response to drought stress. We used the drought-tolerant soybean variety ‘Jiyu 47’ to investigate the differentially expressed proteins (DEPs) in soybean roots during the seedling stage based on the TMT proteomics analysis. Results of enrichment analyses based on a total of 468 DEPs revealed a coordinated expression pattern of proteins involved in various cellular metabolisms responding to drought stress in soybean roots. Our results showed that drought stress caused significant alterations in the expression of proteins involved in several metabolic pathways in soybean roots, including the carbohydrate metabolism, the metabolism of the osmotic regulation substances, and the antioxidant defense system (i.e., the glutathione metabolism). Increased production of reduced glutathione (GSH) enhanced the prevention of the damage caused by reactive oxygen species and the tolerance of the abiotic stress. The glutathione metabolism played a key role in modifying the antioxidant defense system in response to drought stress in soybean roots. Our proteomic study demonstrated that the soybean plants responded to drought stress by coordinating their protein expression during the vegetative stage, providing novel insights into the molecular mechanisms regulating the response to abiotic stress in plants.
Project description:GmMYB176, an R1 MYB transcription factor regulates isoflavonoid biosynthesis in soybean. In the current experiment, GmMYB176 was silenced (GmMYB176-Si) or overexpressed (GmMYB176-OE) in soybean hairy roots and their effect on transcriptome was studied. RNA-Seq analyses of GmMYB176-Si and GmMYB176-OE along with control non-transformed soybean hairy roots revealed that alteration of gene expression of GmMYB176 affects gene regulation of hundreds of genes in soybean.
Project description:We functionally characterized a protein phosphatase, GmHAD1-2, which belongs to haloacid dehalogenase (HAD) family. Suppression of GmHAD1-2 significantly decreased lateral root number and length mainly through affecting naringenin, a kind of flavonoid concentration and auxin accumulation in lateral root primordia and tips. RNA-seq analysis revealed that a total of 726 genes exhibited differential expression patterns between WT and suppression of GmHAD1-2 transgenic soybean plant (Ri). A set of DEGs appeared to be involved in root development, including 16 transcription factors (e.g, GmZATs), 2 cell wall related proteins (i.e, GmEXLB1/2), 29 genes related to auxin and ethylene signaling pathways. The results suggest that a complex transcriptional regulatory network participates in the growth of soybean roots.
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:Microarray experiments were performed on the roots and leaves samples seperately using custom based Nimblgen platform (12plex). This is a time-course study. The plants were grown in controlled growth chamber condiditons ambiient to soybean growth and development using a hydrophonics system. The tissues were harvested after 30days of growth in six time points- 0min, 30mins, 1hour, 2hours, 3hours and 5hours of dehydration.
Project description:Soybean is an important economic crop for human diet, animal feeds and biodiesel due to high protein and oil content. Its productivity is significantly hampered by salt stress, which impairs plant growth and development by affecting gene expression, in part, through epigenetic modification of chromatin status. However, little is known about epigenetic regulation of stress response in soybean roots. Here, we used RNA-seq and ChIP-seq technologies to study the dynamics of genome-wide transcription and histone methylation patterns in soybean roots under salt stress. 8798 soybean genes changed their expression under salt stress treatment. Whole-genome ChIP-seq study of an epigenetic repressive mark, histone H3 lysine 27 trimethylation (H3K27me3), revealed the changes in H3K27me3 deposition during the response to salt stress. Unexpectedly, we found that most of the inactivation of genes under salt stress is strongly correlated with the de novo establishment of H3K27me3 in various parts of the promoter or coding regions where there is no H3K27me3 in control plants. In addition, the soybean histone modifiers were identified which may contribute to de novo histone methylation and gene silencing under salt stress. Thus, dynamic chromatin regulation, switch between active and inactive modes, occur at target loci in order to respond to salt stress in soybean. Our analysis demonstrates histone methylation modifications are correlated with the activation or inactivation of salt-inducible genes in soybean roots.