Expression of ripening-related genes in cold-stored tomato fruit
Adirek Rugkong, Ryan McQuinn, James J. Giovannoni, Jocelyn K.C. Rose and Christopher B. Watkins
Postharvest Biology and Technology, Volume 61, Issue 1, July 2011, Pages 1-14
2011
บทคัดย่อ
The effects of chilling on fruit ripening and the expression of ripening-related genes have been investigated in M82IL2-2, a wild species introgression breeding tomato line (Solanum lycopersicum × Solanum pennellii). Fruit harvested at the breaker stage of ripening were stored at 3 °C for 0, 1, 2 and 4 weeks, followed by 20 °C for 0–14 d. Fruit stored for 1 week ripened normally, as assessed by red color development and softening at 20 °C, but those stored for 2 or 4 weeks showed delayed or inhibited ripening. The concentrations of the carotenoids, phytoene, phytofluene, zeta (ζ)-carotene, gamma (γ)-carotene and lycopene, but not lutein and β-carotene, were reduced in chilled fruit. Microarray analysis showed that after storage at 3 °C for 4 weeks, 352 genes were up-regulated by chilling, whereas 321 genes were down-regulated, while after 7 d at 20 °C, 180 and 126 genes, respectively, were up- and down-regulated in chilled fruit. Chilling-induced changes included expression of transcriptional repressors such as a C2H2-type zinc finger protein. Expression of genes involved in color development, including phytoene synthase1 (PSY1), carotenoid isomerase (CRTISO), geranylgeranyl diphosphate synthase 2 (GGPPS2), and 1-deoxy-d-xylulose-5-phosphate synthase (DXS), showed reduced expression during and after chilling, as did genes encoding the cell wall modifying proteins polygalacturonase (PG), pectin esterase1 (PE1), β-galactosidase (TBG4), expansin1 (LeExp1), and xyloglucan endotransglucosylase-hydrolase 5 (XTH5). Alcohol dehydrogenase 2 (ADH2) and alcohol acyltransferase (AAT) gene expression was also reduced by chilling. Alteration of ethylene production correlated with the altered ACC synthases (ACS2, ACS4), and ACC oxidase (ACO1) expression. The expression of genes involved in the ethylene signal transduction pathway, such as LeETR1, NR, LeETR4, LeCTR1, LeEIL3, LeEIL4, and LeERF3, was altered by chilling, suggesting that ethylene perception and sensitivity were affected. Chilling also reduced gene expression of a ripening-regulated transcription factor, LeMADS-RIN. The effect of chilling on ethylene biosynthesis, ethylene perception, the expression of a transcription factor necessary for ripening, and transcriptional repressors may contribute to the alteration of fruit ripening in tomato.