Project description:The present study profiled and analyzed gene expression of the maize ear at four key developmental stages. Based on genome-wide profile analysis, we detected differential mRNA of maize genes. Some of the differentially expressed genes (DEGs) were predicted to be potential candidates of maize ear development. Several well-known genes were found with reported mutants analyses, such as, compact plant2 (ct2), zea AGAMOUS homolog1 (zag1), bearded ear (bde), and silky1 (si1). MicroRNAs such as microRNA156 were predicted to target genes involved in maize ear development. Antisense transcripts were widespread throughout all the four stages, and are suspected to play important roles in maize ear development. Thus, identification and characterization of important genes and regulators at all the four developmental stages will contribute to an improved understanding of the molecular mechanisms responsible for maize ear development.
Project description:Transformation of the Arabidopsis ATHB17 gene into maize results in the expression of a truncated protein (smaller by 113 amino acids) that functions as a dominant-negative regulator that can modify activity of endogenous maize HD-Zip II transcription factors. This RNASeq experiment indicates that the observed effects of ATHB17d113 on the maize ear inflorescence and ear transcriptome are very small. Expression of ATHB17delta113 protein in maize leads to changes in ear growth resulting in increased ear size at early reproductive stages and, potentially increased sink size.
Project description:Maize (Zea mays L.) is one of the major cereal crops worldwide. Increasing planting density is an effective way to improve crop yield. However, plants grown under high-density conditions compete for water, nutrients, and light, which often leads to changes in productivity. To date, few studies have determined the transcriptomic differences in maize leaves in response to different planting densities. This study examined the whole-genome expression patterns in the leaves of maize planted under high and low densities to identify density-regulated genes. Leaves at upper, ear, and lower stem nodes were collected at the grain-filling stage of the maize hybrid Xianyu335 grown under low-density planting and high-density planting. In total, 72, 733, and 1,739 differentially expressed genes (DEGs) were identified in the respective upper, ear, and lower leaves under HDP. Upregulated and downregulated DEGs in the upper and lower leaves were similar in number, whereas upregulated DEGs in the ear leaves were significantly higher in number than the downregulated DEGs. Functional analysis indicated that genes responding to HDP-related stresses were mediated by pathways involving four phytohormones responsible for metabolism and signaling, osmoprotectant biosynthesis, transcription factors, and fatty acid biosynthesis and protein kinases, which suggested that these pathways are affected by the adaptive responses mechanisms underlying the physiological and biochemical responses of the leaves of maize planted at high density.
Project description:Transformation of the Arabidopsis ATHB17 gene into maize results in the expression of a truncated protein (smaller by 113 amino acids) that functions as a dominant-negative regulator that can modify activity of endogenous maize HD-Zip II transcription factors. This RNASeq experiment indicates that the observed effects of ATHB17d113 on the maize ear inflorescence and ear transcriptome are very small. Expression of ATHB17delta113 protein in maize leads to changes in ear growth resulting in increased ear size at early reproductive stages and, potentially increased sink size. Two ATHB17delta113 expressing events (Event 1 and Event 2) were compared to control plants (herein referred to as WT) in the context of Monsanto Elite Maize hybrid line NN6306. Three bioreps of both Ear inflorescence and Ear tissues were sampled for the WT and each of the two transgenic events.
Project description:The present study profiled and analyzed gene expression of the maize ear at four key developmental stages. Based on genome-wide profile analysis, we detected differential mRNA of maize genes. Some of the differentially expressed genes (DEGs) were predicted to be potential candidates of maize ear development. Several well-known genes were found with reported mutants analyses, such as, compact plant2 (ct2), zea AGAMOUS homolog1 (zag1), bearded ear (bde), and silky1 (si1). MicroRNAs such as microRNA156 were predicted to target genes involved in maize ear development. Antisense transcripts were widespread throughout all the four stages, and are suspected to play important roles in maize ear development. Thus, identification and characterization of important genes and regulators at all the four developmental stages will contribute to an improved understanding of the molecular mechanisms responsible for maize ear development. Seeds of the maize inbred line 18-599 (Maize Research Institute, Sichuan Agricultural University, Chengdu, China) were grown in a growth chamber at 24°C/18°C (day/night) with 12 h illumination per day. Ears were collected as described previously [10] at four developmental stages: the growth point elongation, spikelet differentiation, floret primordium differentiation, and the floret organ differentiation phases. In brief, ears were manually collected at the four developmental stages. All the samples were harvested and immediately frozen in liquid nitrogen, and stored at -80°C until used for RNA isolation.
Project description:Background: Maize plants developed typical gray leaf spot disease (GLS) symptoms initiating at the lower leaves and progressing to upper leaves through the season. Leaf material was collected at 77 days after planting, at which stage there were a large number of GLS disease necrotic lesions on lower leaves (8% surface area on average determined by digital image analysis), but very few lesions and only at chlorotic stage on leaves above the ear (average of 0.2% lesion surface area). Method:To collect material that reflected a difference between C.zeina infected B73 leaves and control B73 leaf material, samples were collected from two lower GLS infected leaves (second and third leaf internode below ear) , and two upper leaves with minimal GLS symptoms (second and third internode above ear), respectively. The two lower leaves from each plant were pooled prior to RNA extraction, and the two upper leaves from each plant were pooled prior to RNA extraction. Upper and lower leaf samples from three maize B73 plants were subjected to RNA sequencing individually. The three maize plants were selected randomly as one plant per row from three rows of ten B73 plants each. Result: A systems genetics strategy revealed regions on the maize genome underlying co-expression of genes in susceptible and resistance responses, including a set of 100 genes common to the susceptible response of sub-tropical and temperate maize.
Project description:Small RNAs (sRNAs) are hypothesized to contribute to hybrid vigor because they maintain genome integrity, contribute to genetic diversity, and control gene expression. We used Illumina sequencing to assess how sRNA populations vary between two maize inbred lines (B73, Mo17) and their hybrid. We sampled sRNAs from the seedling shoot apex and the developing ear, two rapidly growing tissues that program the greater growth of maize hybrids. We found that parental differences in siRNAs primarily originate from repeat regions. Although the maize genome contains greater number and complexity of repeats compared to Arabidopsis or rice, we confirmed that like these simpler plant genomes, 24-nt siRNAs whose abundance differs between maize parents also show a trend of downregulation following hybridization. Surprisingly, hybrid vigor is fully maintained when 24-nt siRNAs are globally reduced by mutation of the RNA-dependent RNA polymerase2 (RDR2) encoded by modifier of paramutation1 (mop1). We also discovered that 21-22nt siRNAs derived from a number of distinct retrotransposon families differentially accumulate between B73 and Mo17 as well as their hybrid. Thus, maize possesses a novel source of genetic variation for regulating both transposons and genes at a genomic scale, which may contribute to its high degree of observed heterosis.