Differential Gene Expression During Bud Dormancy in Malus x domestica Borkh. variety Anna

Chill requirement in fruit trees is a great concern for apple producers in the temperate sub Saharan countries. Northern Hemisphere apple producing countries receive more than 1500 hours chill annually whereas in comparison South Africa receives less than 800 hours of chill annually. Trees are not able to meet chill requirement during endodormancy.  This causes reduced branching, erratic flowering and therefore erratic fruiting. The mechanism of endodormancy is not well understood. In this study RNA-Seq was used in an effort to elucidate this mechanism. RNA was extracted at set time intervals from the buds of a low chill apple variety Anna before the onset of endodormancy. RNA samples were sequenced using the Illumina TruSeq mRNA-Seq technology.  Differential gene expression patterns where characterised using the Tuxedo suite and CLC Genomics Workbench™ as bioinformatics tools. A number of transcripts were highlighted as being differentially expressed between time intervals. Some of these transcripts were homologous to DORMANCY ASSOCIATED MADS BOX and FLOWERING LOCUS T found in Arabidopsis thaliana. Specific transcription factors were also detected as being differentially expressed.