Location: Plant, Soil and Nutrition ResearchTitle: Regulatory control of carotenoid accumulation in winter squash during storage
|Zhang, Ming Ke - Cornell University - New York|
|Zhang, Mei Ping - Cornell University - New York|
|Mazourek, Michael - Cornell University - New York|
|Tadmor, Yaakov - Agricultural Research Organization Of Israel|
Submitted to: Planta
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/7/2014
Publication Date: 8/20/2014
Citation: Zhang, M., Zhang, M., Mazourek, M., Tadmor, Y., Li, L. 2014. Regulatory control of carotenoid accumulation in winter squash during storage. Planta. 240:1063-1074.
Interpretive Summary: Carotenoids are indispensable for human nutrition and health. While extensive studies of carotenogenesis have been carried out in plants, very little is known about carotenoid accumulation and regulation during postharvest storage, a process that is required for both consumption and food processing markets. In this study, we found that storage of a winter squash leads to a continuous increase of carotenoid accumulation, concomitant with starch breakdown and the conversion of amylochromoplasts into chromoplasts. We showed that the increased carotenoid levels are not due to increased capacity of biosynthesis, but likely result from a continuous biosynthesis with a reduced rate of turnover and/or enhanced sequestration. This work provides important information to our understanding of carotenogenesis and its regulation during postharvest storage of fruits.
Technical Abstract: Postharvest storage of fruits and vegetables is often required and frequently results in nutritional quality change. In this study, we investigated carotenoid storage plastids, carotenoid content, and its regulation during 3-month storage of winter squash butternut fruits. We showed that storage improved visual appearance of fruit flesh color from light to dark orange, and promoted continuous accumulation of carotenoids during the first 2-month storage. Such an increased carotenoid accumulation was found to be concomitant with starch breakdown, resulting in the conversion of amylochromoplasts into chromoplasts. The butternut fruits contained predominantly B-carotene, lutein and violaxanthin. Increased ratios of B-carotene and violaxanthin to total carotenoids were noticed during the storage. Analysis of carotenoid metabolic gene expression and PSY protein level revealed that the increased carotenoid level was not due to increased capacity of biosynthesis. Instead, the increase was likely resulted from a continuous biosynthesis with a reduced turnover and/or enhanced sequestration, suggesting a complex regulation of carotenoid accumulation during fruit storage. This study provides important information to our understanding of carotenogenesis and its regulation during postharvest storage of fruits.