Alteration of the embryo transcriptome of hexaploid winter wheat (Triticum aestivum cv. Mercia) during maturation and germination

Abstract

Grain dormancy and germination are areas of biology that are of considerable interest to the cereal community. We have used a 9,155-feature wheat unigene cDNA microarray resource to investigate changes in the wheat embryo transcriptome during late grain development and maturation and during the first 48 h of postimbibition germination. In the embryo 392 mRNAs accumulated by twofold or greater over the time course from 21 days postanthesis (dpa) to 40 dpa and on through 1 and 2 days postgermination. These included mRNAs encoding proteins involved in amino acid biosynthesis and metabolism, cell division and subsequent cell development, signal transduction, lipid metabolism, energy production, protein turnover, respiration, initiation of transcription, initiation of translation and ribosomal composition. A number of mRNAs encoding proteins of unknown function also accumulated over the time course. Conversely 163 sequences showed decreases of twofold or greater over the time course. A small number of mRNAs also showed rapid accumulation specifically during the first 48 h of germination. We also examined alterations in the accumulation of transcripts encoding proteins involved in abscisic acid signalling. Thus, we describe changes in the level of transcripts encoding wheat Viviparous 1 (Vp1) and other interacting proteins. Interestingly, the transcript encoding wheat Viviparous-interacting protein 1 showed a pattern of accumulation that correlates inversely with germination. Our data suggests that the majority of the transcripts required for germination accumulate in the embryo prior to germination and we discuss the implications of these findings with regard to manipulation of germination in wheat.

A Wheat Homolog of MOTHER OF FT AND TFL1 Acts in the Regulation of Germination

“…Several transcriptomic analyses on seed development and germination have been reported in wheat and barley (Hordeum vulgare; Wilson et al, 2005;Sreenivasulu et al, 2008;Wan et al, 2008). Numerous transcriptome analyses have examined expression profiles during seed development and germination in Arabidopsis thaliana.…”

Mapping Metabolic and Transcript Temporal Switches during Germination in Rice Highlights Specific Transcription Factors and the Role of RNA Instability in the Germination Process

“…While some transcriptome studies in wheat (Triticum aestivum) and barley have been performed (Watson and Henry, 2005;Wilson et al, 2005;Sreenivasulu et al, 2008), the lack of complete genome sequence data prevents comprehensive whole transcriptome analysis, including promoter analysis once coexpressed gene sets have been identified. For example, the most comprehensive transcriptome study in monocots to date, using barley (Sreenivasulu et al, 2008), reported that cis element searches were performed in homologous rice (Oryza sativa) promoters, as this sequence information is not yet available for barley.…”

Expression of the aldehyde oxidase 3, ent-copalyl diphosphate synthase, and VIVIPAROUS 1 genes in wheat cultivars differing in their susceptibility to pre-harvest sprouting

“…In wheat, the highest expression level of the VP1 gene is observed at about 50 DAP, later on -in the ripening stage (60 DAP)-it drops down (Utsugi et al, 2008). However, Wilson et al (2005) found that the expression of the VP1 gene peaked about 21 DAP, and at further stages, until 40 DAP, decreased. In our experiments in both examined cultivars, two peaks of the VP1 gene expression were observed.…”