Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 3/15/2007
Publication Date: 7/1/2007
Citation: Mccollum, T.G., Maul, P., Guy, C., Porat, R. 2007. Temperature conditioning alters transcript abundance of genes related to chilling stress in grapefruit. [abstract] HortScience. 42(4):981-982. Interpretive Summary:
Technical Abstract: Grapefruit (Citrus paradisi) are susceptible to chilling injury (CI) if held at temperatures below about 10C. Changes in transcript abundance for a number of genes have been correlated with chilling stress in citrus fruit. We tested the hypothesis that conditioning affects transcript abundance of genes related to chilling stress in grapefruit. Grapefruit were harvested from a commercial grove in Florida in September and divided into two groups; one group was placed immediately at 5C (non-conditioned (NC)); the second group was placed at 16C for one week (conditioned (C)) and then transferred to 5C. Symptoms of CI were visible on NC and C fruit following 14 days at 5C, but were consistently more severe on NC than C fruit. Storage at 5C caused increases in abundance of transcripts for ACO, galactinol synthase, a chilling induced oxygenase, and a temperature induced-lipocalin, consistent with previous reports. Levels of these transcripts were lower in C than in NC fruit during storage at 5C, but this pattern did not persist following transfer to 20C. Levels of transcripts for catalase, a metallothionein-like protein, a lipid transfer protein, a stress-responsive zinc finger protein, and a citrus low temperature-inducible protein were consistently higher in C than NC fruit during storage at 5C. Our results confirm that conditioning increases chilling tolerance in grapefruit and demonstrates that abundance of transcripts of a number of genes related to chilling stress is affected by conditioning. We cannot say, however, that these changes are related to chilling tolerance per se or whether they merely reflect the difference in chilling tolerance. This research was supported by BARD Research Grant No. IS-3499-03R.