Co-Authors:
Hershkovitz, V., Department of Postharvest Science of Fresh Produce, The Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
Friedman, H., Department of Postharvest Science of Fresh Produce, The Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
Goldschmidt, E.E., The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
Pesis, E., Department of Postharvest Science of Fresh Produce, The Volcani Center, P.O. Box 6, Bet Dagan, 50250, Israel
Abstract:
We studied the contribution of the seed to avocado ripening, emphasizing its role in ethylene biosynthesis and response pathways. Transcription profiles of genes involved in ethylene biosynthesis (PaACO, PaACS1 and PaACS2) and action (PaETR, PaERS1 and PaCTR1) were studied in seeded and seedless avocado fruit during ripening at ambient and low temperatures and in response to exogenous ethylene and 1-methylcyclopropene (1-MCP). Seedless mature fruit had a shorter preclimacteric lag, faster softening, and higher respiration during ambient temperature ripening than seeded ones. Advanced ripening in seedless fruit was accompanied by higher levels of PaACO and PaACS1 expression at harvest, and these levels increased dramatically towards the climacteric peak. The expression of PaETR, PaERS1 and PaCTR1 increased in parallel with the onset of the ethylene burst in seedless fruit, whereas PaETR increase predominantly in seeded ones. Seedless fruit exhibited an earlier response to exogenous ethylene at the day of harvest, than seeded fruit. On day 1 after harvest, ethylene application elicited lower levels of ethylene in seeded than in seedless fruit, concomitantly with massive PaCTR1 augmentation. This suggests that the negative regulator PaCTR may moderate the effect of ethylene on seeded fruit. Cold storage induced biosynthesis and regulatory genes in both seedless and seeded fruit relative to their levels at ambient temperature. However, in the first and second weeks in cold storage, PaACO, PaACS1 and PaACS2 expression levels were much higher in seedless than in seeded fruit, which could explain the higher levels of ethylene and accelerated softening of the seedless fruit in cold storage. Seeded and seedless fruit responded similarly to ethylene or 1-MCP application prior to cold storage. Ethylene slightly induced ethylene production, but significantly increased CO2 output. 1-MCP equally and effectively delayed softening, reduced ethylene and CO2 production and expression of genes involved in ethylene biosynthesis and ethylene action in seeded and seedless fruit. Both at ambient temperature and in cold storage respiration was higher in seedless than seeded fruit. Our findings demonstrate that the seed is involved in regulation of ethylene responsiveness during ripening, and acts to delay climacteric in mature seeded fruit. © 2010 Elsevier B.V. All rights reserved.
תפריט נגישות
ניגודיות עדינה
מונוכרום
הדגשת קישורים
חסימת אנימציה
פונט קריא
סגור
איפוס הגדרות נגישות
להורדת מודול נגישות חינם
