Project description:In this study, we used RNA-seq to obtain and compare transcriptomic profiles of a resistant genotype J11 in pre-harvest seeds, with A. flavus inoculation at the whole-genome level. The TMT method was also implemented to help further understand the molecular mechanism of peanut resistance to A. flavus invasion at proteome level. Meanwhile, we conducted a thorough research on a chitinase and a NBS-LRR gene, which were found in our data. This study is our first step towards a comprehensive genome-scale platform for developing Aspergillus resistant peanut cultivars through genetic engineering.
Project description:To identify peanut Aspergillus-interactive and Aspergillus-resistance genes, we carried out a large scale peanut Expressed Sequence Tag (EST) project followed by a peanut microarray study. For expression profiling, resistant and susceptible peanut cultivars were infected with a mixture of Aspergillus flavus and parasiticus spores. Microarray analysis identified 65 and 1 genes in resistant (C20) and susceptible (TF) cultivars, respectively, that were up-regulated in response to Aspergillus infection. In addition we identified 40 putative Aspergillus-resistance genes that were constitutively up-expressed in the resistant cultivar in comparison to the susceptible cultivar. Some of these genes were homologous to peanut, corn, and soybean genes previously shown to confer resistance to fungal infection. These results provide a comprehensive genome-scale platform for future studies focused on developing Aspergillus-resistant peanut cultivars through conventional breeding, marker-assisted breeding, or biotechnological methods by gene manipulation.
Project description:Aflatoxin contamination caused by Aspergillus flavus in peanut is a serious constraint for food safety and human health. However, molecular mechanism/s underlying the defense response is poorly understood. A comparative proteomic analysis was carried out between two contrasting peanut genotypes, JL24 (WT-susceptible) and a near-isogenic transgenic event (OE-Def) in the same background expressing defensin gene (resistant) with different time points, To understand the proteome changes in OE-Def and WT control lines, a label-free quantitative proteomics analysis was performed at 0, 24, 40, 56 and 72 h after A. flavus inoculation using UPLC-ESI-MS/MS. Several resistance proteins in the secondary metabolic pathways related to phenylpropanoids, flavonoids, and fatty acid biosynthesis were strongly induced in the resistant genotype.
Project description:To identify peanut Aspergillus-interactive and Aspergillus-resistance genes, we carried out a large scale peanut Expressed Sequence Tag (EST) project followed by a peanut microarray study. For expression profiling, resistant and susceptible peanut cultivars were infected with a mixture of Aspergillus flavus and parasiticus spores. Microarray analysis identified 65 and 1 genes in resistant (C20) and susceptible (TF) cultivars, respectively, that were up-regulated in response to Aspergillus infection. In addition we identified 40 putative Aspergillus-resistance genes that were constitutively up-expressed in the resistant cultivar in comparison to the susceptible cultivar. Some of these genes were homologous to peanut, corn, and soybean genes previously shown to confer resistance to fungal infection. These results provide a comprehensive genome-scale platform for future studies focused on developing Aspergillus-resistant peanut cultivars through conventional breeding, marker-assisted breeding, or biotechnological methods by gene manipulation. Four samples were analyzed with four hybs. Two samples were obtained from resistant (C20) and and susceptible (TF) cultivars. Two factors were varied in the experimental design: (i) peanut cultivars (resistant (GT-C20) and susceptible (TF)) and (ii) Aspergillus exposure. A combination of these factors produced four hybridizations as follows: (1) C20Y vs. TFY (GT-C20 infected vs. TF infected) (2) C20Y vs. C20N (GT-C20 infected vs. not infected) (3) TFY vs. TFN (TF infected vs. not infected) (4) C20N vs. TFN (GT-C20 not infected vs. TF not infected)
Project description:Seed expansion in peanut is a complex biological process involving many gene regulatory pathways. MicroRNAs (miRNAs) play important regulatory roles in plant growth and development, but little is known about their functions during seed expansion, or how they contribute to seed expansion in different peanut lines. We examined seed miRNA expression patterns at 15 and 35 days after flowering ( DAF ) in two peanut 8th generation recombinant inbred lines (RIL8); 8106, a medium-pod variety, and 8107, a super-pod variety. Using high-throughput sequencing, we identified 1082 miRNAs in developing peanut seeds including 434 novel miRNAs. We identified 316 differentially expressed miRNAs by comparing expression levels between the two peanut lines. Interestingly, 24 miRNAs showed contrasting patterns of expression in the two RILs, and 149 miRNAs were expressed predominantly in only one RIL at 35 DAF. Also, potential target genes for some conserved and novel miRNAs were identified by degradome sequencing; target genes were predicted to be involved in auxin mediated signaling pathways and cell division. We validated the expression patterns of some representative miRNAs and 12 target genes by qPCR, and found negative correlations between the expression level of miRNAs and their targets. miR156e, miR159b, miR160a, miR164a, miR166b, miR168a, miR171n, miR172c-5p, and miR319d and their corresponding target genes may play key roles in seed expansion in peanut. The results of our study also provide novel insights into the dynamic changes in miRNAs that occur during peanut seed development, and increase our understanding of miRNA function in seed expansion.
Project description:Investigation of resistance genes from 36,158 peanut ESTs after salt stress treatment, compared with untreated peanut. Yield some useful insights into salt-mediated signal transduction pathways in peanut.
Project description:Investigation of resistance genes from 36,158 peanut ESTs after cold stress treatment, compared with untreated peanut. Yield some useful insights into cold-mediated signal transduction pathways in peanut.