Dataset Information

DNA methylation and gene expression regulation associated with vascularization in Sorghum bicolor.

ABSTRACT: Plant secondary cell walls constitute the majority of plant biomass. They are predominantly found in xylem cells, which are derived from vascular initials during vascularization. Little is known about these processes in grass species despite their emerging importance as biomass feedstocks. The targeted biofuel crop Sorghum bicolor has a sequenced and well-annotated genome, making it an ideal monocot model for addressing vascularization and biomass deposition. Here we generated tissue-specific transcriptome and DNA methylome data from sorghum shoots, roots and developing root vascular and nonvascular tissues. Many genes associated with vascular development in other species show enriched expression in developing vasculature. However, several transcription factor families varied in vascular expression in sorghum compared with Arabidopsis and maize. Furthermore, differential expression of genes associated with DNA methylation were identified between vascular and nonvascular tissues, implying that changes in DNA methylation are a feature of sorghum root vascularization, which we confirmed using tissue-specific DNA methylome data. Roots treated with a DNA methylation inhibitor also showed a significant decrease in root length. Tissues and organs can be discriminated based on their genomic methylation patterns and methylation context. Consequently, tissue-specific changes in DNA methylation are part of the normal developmental process.

SUBMITTER: Turco GM

PROVIDER: S-EPMC5655736 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature

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DNA methylation and gene expression regulation associated with vascularization in Sorghum bicolor.

Turco Gina M GM Kajala Kaisa K Kunde-Ramamoorthy Govindarajan G Ngan Chew-Yee CY Olson Andrew A Deshphande Shweta S Tolkunov Denis D Waring Barbara B Stelpflug Scott S Klein Patricia P Schmutz Jeremy J Kaeppler Shawn S Ware Doreen D Wei Chia-Lin CL Etchells J Peter JP Brady Siobhan M SM

The New phytologist 20170210 3

Plant secondary cell walls constitute the majority of plant biomass. They are predominantly found in xylem cells, which are derived from vascular initials during vascularization. Little is known about these processes in grass species despite their emerging importance as biomass feedstocks. The targeted biofuel crop Sorghum bicolor has a sequenced and well-annotated genome, making it an ideal monocot model for addressing vascularization and biomass deposition. Here we generated tissue-specific tr ...[more]

PMID: 28186631

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Project description:Plant secondary cell walls constitute the majority of plant biomass and are an important source of biomaterials. Secondary cell walls are particularly prominent in xylem cells present in the vascular tissue. Although the process of vascularization has been extensively studied in the dicot Arabidopsis thaliana, remarkably little is known about these processes in grass species despite their emerging importance as biomass feedstocks. The targeted biofuel crop Sorghum bicolor has a sequenced and well-annotated genome, making it an ideal monocot model for addressing vascularization and biomass deposition. Here we generated tissue-specific transcriptome data using laser capture microdissection in the developing vascular and non-vascular tissues of the sorghum root. Many sorghum genes with enriched expression in developing vasculature were orthologous to genes previously associated with vascular development in other species. However, a number of transcription factor families, including NAC domain, MYB and ARF varied in their complement of vascular expressed genes to a considerable degree in sorghum compared to Arabidopsis and/or maize. Differential expression of genes associated with DNA methylation and chromatin modification were identified between vascular and non-vascular cell types, implying that changes in DNA methylation may be a feature of sorghum root vascularization. To profile DNA methylation in these tissues, sodium bisulfite sequencing of laser capture microdissected tissue was performed. DNA methylation was enriched in genic regions of genes demonstrating higher expression in non-vascular tissues. Methylation in genic and intergenic regions varied by tissue type and gene expression level. Furthermore, genes involved in cell elongation showed differences in methylation levels concomitant with expression between non-vascular and vascular tissue types suggesting a novel mode by which root growth in distinct tissues may be modulated. Our results provide both a genetic and epigenetic framework for studying vascularization and secondary cell wall development in sorghum.

Project description:Main conclusionDevelopmental and organ-specific expression of genes in dhurrin biosynthesis, bio-activation, and recycling offers dynamic metabolic responses optimizing growth and defence responses in Sorghum. Plant defence models evaluate the costs and benefits of resource investments at different stages in the life cycle. Poor understanding of the molecular regulation of defence deployment and remobilization hampers accuracy of the predictions. Cyanogenic glucosides, such as dhurrin are phytoanticipins that release hydrogen cyanide upon bio-activation. In this study, RNA-seq was used to investigate the expression of genes involved in the biosynthesis, bio-activation and recycling of dhurrin in Sorghum bicolor. Genes involved in dhurrin biosynthesis were highly expressed in all young developing vegetative tissues (leaves, leaf sheath, roots, stems), tiller buds and imbibing seeds and showed gene specific peaks of expression in leaves during diel cycles. Genes involved in dhurrin bio-activation were expressed early in organ development with organ-specific expression patterns. Genes involved in recycling were expressed at similar levels in the different organ during development, although post-floral initiation when nutrients are remobilized for grain filling, expression of GSTL1 decreased > tenfold in leaves and NITB2 increased > tenfold in stems. Results are consistent with the establishment of a pre-emptive defence in young tissues and regulated recycling related to organ senescence and increased demand for nitrogen during grain filling. This detailed characterization of the transcriptional regulation of dhurrin biosynthesis, bioactivation and remobilization genes during organ and plant development will aid elucidation of gene regulatory networks and signalling pathways that modulate gene expression and dhurrin levels. In-depth knowledge of dhurrin metabolism could improve the yield, nitrogen use efficiency and stress resilience of Sorghum.

Project description:Recent efforts to engineer C4 photosynthetic traits into C3 plants such as rice demand an understanding of the genetic elements that enable C4 plants to outperform C3 plants. As a part of the C4 Rice Consortium's efforts to identify genes needed to support C4 photosynthesis, EMS mutagenized sorghum populations were generated and screened to identify genes that cause a loss of C4 function. Stable carbon isotope ratio (δ13C) of leaf dry matter has been used to distinguishspecies with C3 and C4 photosynthetic pathways. Here, we report the identification of a sorghum (Sorghum bicolor) mutant with a low δ13C characteristic. A mutant (named Mut33) with a pale phenotype and stunted growth was identified from an EMS treated sorghum M2 population. The stable carbon isotope analysis of the mutants showed a decrease of 13C uptake capacity. The noise of random mutation was reduced by crossing the mutant and its wildtype (WT). The back-cross (BC1F1) progenies were like the WT parent in terms of 13C values and plant phenotypes. All the BC1F2 plants with low δ13C died before they produced their 6th leaf. Gas exchange measurements of the low δ13C sorghum mutants showed a higher CO2 compensation point (25.24 μmol CO2.mol-1air) and the maximum rate of photosynthesis was less than 5μmol.m-2.s-1. To identify the genetic determinant of this trait, four DNA pools were isolated; two each from normal and low δ13C BC1F2 mutant plants. These were sequenced using an Illumina platform. Comparison of allele frequency of the single nucleotide polymorphisms (SNPs) between the pools with contrasting phenotype showed that a locus in Chromosome 10 between 57,941,104 and 59,985,708 bps had an allele frequency of 1. There were 211 mutations and 37 genes in the locus, out of which mutations in 9 genes showed non-synonymous changes. This finding is expected to contribute to future research on the identification of the causal factor differentiating C4 from C3 species that can be used in the transformation of C3 to C4 plants.

Dataset Information

DNA methylation and gene expression regulation associated with vascularization in Sorghum bicolor.

Publications

DNA methylation and gene expression regulation associated with vascularization in Sorghum bicolor.

Similar Datasets

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