Transcription profiling of the chilling requirement for bud break in apples: a putative role for FLC-like genes.
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.
Centro de Pesquisa Agropecuária do Trópico Semi-Árido, Empresa Brasileira de Pesquisa Agropecuária, BR-428, Km 152, 56302-970, Petrolina, PE, Brazil.
Diogo Denardi
DD
Porto
Institut de Recherche en Horticulture et Semences (IRHS), A, 42 rue Georges Morel, 49071 Beaucouzé Cedex, France.
Maryline
M
Bruneau
Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Sul, Rua General Osório, 348, Centro, 95700-000, Bento Gonçalves, RS, Brazil.
Pâmela
P
Perini
Fundação Estadual de Pesquisa Agropecuária, RSC-470, Km 170, 95330-000, Veranópolis, RS, Brazil.
Rafael
R
Anzanello
Institut de Recherche en Horticulture et Semences (IRHS), A, 42 rue Georges Morel, 49071 Beaucouzé Cedex, France.
Jean-Pierre
JP
Renou
Centro Nacional de Pesquisa de Uva e Vinho, Empresa Brasileira de Pesquisa Agropecuária, Rua Livramento, 515, 95700-000, Bento Gonçalves, RS, Brazil.
Henrique Pessoa
HP
dos Santos
Centro Nacional de Pesquisa de Uva e Vinho, Empresa Brasileira de Pesquisa Agropecuária, Rua Livramento, 515, 95700-000, Bento Gonçalves, RS, Brazil.
Flávio Bello
FB
Fialho
Centro Nacional de Pesquisa de Uva e Vinho, Empresa Brasileira de Pesquisa Agropecuária, Rua Livramento, 515, 95700-000, Bento Gonçalves, RS, Brazil luis.revers@embrapa.br.
Luís Fernando
LF
Revers
D057906:Circadian Clocks; D016000:Cluster Analysis; D003080:Cold Temperature; D005419:Flavonoids / Q000096:biosynthesis; D035264:Flowers / Q000235:genetics / Q000254:growth & development; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D027845:Malus / Q000235:genetics* / Q000254:growth & development; D020411:Oligonucleotide Array Sequence Analysis; D040641:Quantitative Trait Loci; D012621:Seasons; D015398:Signal Transduction
D005419:Flavonoids
Apple; Castel Gala; FLC-like; Royal Gala.; bud dormancy; chilling requirement; microarray