Expression profile of transcripts encoding cell wall remodelling proteins in tomato fruit cv. Micro-Tom subjected to 15°C storage.

To extend fruit market life, tomatoes are harvested before red ripe and kept at temperatures below optimum (20°C). In this work, Micro-Tom tomatoes stored at 20°C (normal ripening) were compared with those stored at 15°C or 4°C (chilling injury inducer) for 7 days. In contrast to 4°C, storage at 15°C delayed ripening with the benefit of not enhancing oxidative metabolism and of enabling ripening upon being transferred to 20°C. The transcriptional expression profile of enzymes related to cell wall metabolism was compared at the three temperatures. Although endo-β-1,4-glucanase (Cel1), which is associated with fruit decay, was largely increased after removal from 4°C storage, its expression was not modified in fruits stored at 15°C. Enhanced transcriptional expression of xyloglucan endotransgylcosylase/hydrolases (XTHs) XTH1, -2, -10 and -11, and of two β-xylosidases (Xyl1-2) was detected in fruits stored at 15°C with respect to those at 20°C. Following 2 days at 20°C, these transcripts remained higher in fruits stored at 15°C and XHT3 and -9 also increased. Ethylene evolution was similar in fruits kept at 15°C and 20°C; thus, the changes in the transcript profile and fruit properties between these treatments may be under the control of factors other than ethylene.