For the 800 chill unit bud library, the top four categories were binding, catalytic activity, transcriptional regulator activity, and structural molecule activity.
The chill unit accumulation of <7.2 °C chill units model has previously been shown to be the most accurate model in predicting chill satisfaction and timing of bud break of three blackcurrant cultivars in the field (Rose and Cameron 2009).
Flower buds were collected from field plants during the fall and winter of 2006-2007 wincreasingsing exposure to chilling temperatures, measured as chill units (hours between 0-7°C 0-7°C
To verify how winter warming influenced the spring event, we designed different winter chill units treatments to simulate different degrees of warming conditions.
The distribution of sequences from the fourth bud library (~1300 chill units), which represents transcripts during deacclimation, was most different from the other three libraries.
According to this model, which sums up the total number of hours below 7.2 °C, the number of chill units had exceeded 2000 in both plots in mid-February.
Cold hardiness reaches a maximum level (or minimum LT50) of about -25 to -27°C by about mid to late December (~600 chill units), and buds begin to deacclimate in February and reach a cold hardiness level of about -13 to -14°C by late March ~13000 chill units) [ 22, 23].
Under biological processes, the distribution of sequences from the first two bud libraries (0 and ~400 chill units), representing transcripts at early and middle stages of cold acclimation, were most similar.
Total RNA was isolated from the leaf and four bud (0, 397, 789, and 1333 chill units) samples by a modification of the method of Chang et al. [ 44].
The nine cDNAs (from leaves, flower buds collected at 0, 39789789, and 1333 chill units, and fruit collected at green, white, pink, and blue fruit stages) were provided to the Genomic Sciences Laboratory, North Carolina State University, for library construction and 454 sequencing.
Under molecular function, the top four categories for the three bud libraries (0, 400, and 1300 chill units) were binding, catalytic activity, structural molecule activity, and transcription regulator activity.
