Transcription profiling of the chilling requirement for bud break in apples: a putative role for FLC-like genes

Abstract

Apple production depends on the fulfilment of a chilling requirement for bud dormancy release. Insufficient winter chilling results in irregular and suboptimal bud break in the spring, with negative impacts on apple yield. Trees from apple cultivars with contrasting chilling requirements for bud break were used to investigate the expression of the entire set of apple genes in response to chilling accumulation in the field and controlled conditions. Total RNA was analysed on the AryANE v.1.0 oligonucleotide microarray chip representing 57,000 apple genes. The data were tested for functional enrichment, and differential expression was confirmed by real-time PCR. The largest number of differentially expressed genes was found in samples treated with cold temperatures. Cold exposure mostly repressed expression of transcripts related to photosynthesis, and long-term cold exposure repressed flavonoid biosynthesis genes. Among the differentially expressed selected candidates, we identified genes whose annotations were related to the circadian clock, hormonal signalling, regulation of growth, and flower development. Two genes, annotated as FLOWERING LOCUS C-like and MADS AFFECTING FLOWERING, showed strong differential expression in several comparisons. One of these two genes was upregulated in most comparisons involving dormancy release, and this gene's chromosomal position co-localized with the confidence interval of a major quantitative trait locus for the timing of bud break. These results indicate that photosynthesis and auxin transport are major regulatory nodes of apple dormancy and unveil strong candidates for the control of bud dormancy.

A comparative transcriptomic approach to understanding the formation of cork

“…EgMYB1 can interact with a linker histone and it has been hypothesized that it represses the phenylpropanoid biosynthetic enzymes through chromatin remodeling (Soler et al 2017). FLC (FLOWERING LOCUS C) is a floral repressor that integrates vernalization responses (Sheldon et al 2000) and in perennial trees an FLC-like gene has also been highlighted as a candidate for bud dormancy regulation (Porto et al 2015). FLC regulation is basically performed by chromatin remodelling since FLC expression is epigenetically regulated (Shindo et al 2006;Jung et al 2013;Crevillén et al 2014).…”

Recent Advances in Genetics and Molecular Control of Bud Dormancy in Pipfruits

“…One of the most noteworthy results was the transcriptional profile obtained for a DAM-like gene, whose expression was very similar to peach PpDAM5 and PpDAM6 genes (Li et al 2009;Yamane et al 2011). In an independent approach, Porto et al (2015) carried out a transcriptomic assay aiming to analyze changes in apple gene (~ 57,000) expression in response to chilling accumulation in the field and under controlled conditions using a microarray chip. Cold exposure mainly repressed the expression of transcripts related to photosynthesis, whereas long-term cold exposure repressed flavonoid biosynthesis genes.…”

The hot, the cold and the tulip : the regulation of flowering time and dormancy release

“…Growers plant the mother bulbs, containing a floral bud, in autumn and they will be replaced by daughter bulbs in the Complex 2 (PRC2) (Kim and Sung, 2014). However, FLC dependent regulation of the vernalization response seems mostly restricted to the Brassicaceae, with the exceptions of Beta vulgaris (sugar beet), Brachypodium distachyon (Purple false brome) and Malus domestica (apple) (Reeves et al, 2007;Alexandre and Hennig, 2008;Ruelens et al, 2013;Porto et al, 2015). In cereals, such as Hordeum vulgare …”