2008 Annual Report
1a.Objectives (from AD-416)
The focus of the objectives in this proposal is improving quality and reducing postharvest loss of deciduous tree fruit (chiefly apples, pears and cherries). Our investigations will lead to new knowledge concerning biochemical and molecular causes of physiological disorders, that curative technologies can be developed and implemented, and identification of genes and gene regulatory mechanisms governing such fruit quality characteristics as texture, flavor, and phytonutrient content.
Objective 1. Determine how pre- and postharvest factors influence the development of physiological storage disorders of apples.
1.a. Determine effect of pre- and postharvest environment on fruit epidermal tissue development and onset of physiological peel disorders.
1.b. Identify physiological, biochemical and molecular changes during fruit maturation and storage associated with development of internal browning.
Objective 2. Identify genes regulating firmness loss and carotenoid metabolism in apple.
1b.Approach (from AD-416)
The tree fruit industry's survival in the United States depends on its ability to develop and utilize new technologies to reduce costs while improving quality. The genetic basis for critical elements determining fruit quality and nutritive value of apple, pear, and sweet cherry fruit is poorly understood and can be addressed using new technologies in molecular genetics that can lead to improved cultivars. We propose to identify influence of preharvest factors on biochemical and physiological changes of fruit epidermis that influence onset of lenticel breakdown in storage by refining experiments to examine changes in wax quality with stress and C2H4 regulators. Refine analytical methods for wax analysis. Identify biochemical and physiological changes during fruit matuation and storage that influence onset of internal browning by repeating first year experiments using whole fruit exposed to CO2 enriched atmospheres and identify oxidizing species accumulating in DPA. Determine proper state of highest quality of fruit agter storage by repeating first year experiments on multiple new cultivars of apples and evaluate the response of newcultivars to various pre- and postharvest conditions. Complete experiments on ethyl bromide alternative for quarantine treatments for effects on fruit quality and storage disorders using microwave energy.
Replacing 5350-43000-05-00-D 08/06
The effect of sustained preharvest humidity on apple frut cuticle was examined using water-impervious bags. During the first 3 weeks of fruit growth, changes in the composition of the epidermal wax of bagged ‘Fuji’ or ‘Gala’ apples were evident within 48 hours of bagging. Based on these results, ‘Gala’ and ‘Golden Delicious’ fruit were enclosed in bags in June and the bag removed after 30 or 60 days. Also included as treatments were fruit without bags and fruit with bags in place through harvest. Within 20 days of harvest during storage at -1 °C, symptoms of moisture loss (shrivel and lenticel pitting) increased with pre-harvest bag duration whereas unbagged fruit had no symptoms. Bagging-induced changes in the relative humidity of the immediate fruit growing environment were reflected in fruit cuticle with altered thickness and composition.
Development of the apple peel physiological disorder superficial scald was studied at the molecular level. Suppressive subtraction hybridization of peel gene expression during the initial postharvest storage period of susceptible (‘Granny Smith’) and resistant (‘Golden Delicious’) apples indicated a number of genes related to oxidative metabolism and detoxification pathways are up and down regulated, respectively, during the initial stages of scald development.
‘Braeburn’ apples, highly susceptible to development of CO2-induced internal browning, were treated at harvest with 0 or 2000 µL¿L-1 diphenylamine (a browning inhibitor) and stored at 1oC in air or in 1.5 kPa O2 and 1, 2, or 3 kPa CO2 for 1 or 2 months. The metabolic profile of damaged and healthy cortex samples was evaluated at harvest and following storage using GC-MS analysis of trimethylsilyl (oxime) derivatives. Principal component analysis of the metabolic profile revealed metabolomic shifts resulting from differing tissue integrity, diphenylamine treatment, hypoxic storage, CO2 concentration, and storage duration. The results indicate changes in primary and secondary metabolism occur in relation to all of the postharvest factors evaluated, and demonstrate that this subset of the metabolome is representative of metabolic perturbations associated with browning.
Genetic variation in Md-ACS1 and Md-ACO1, two markers for fruit ethylene production, in 5000 seedlings in the Washington State University Apple Breeding Program was conducted to identify seedlings with a high potential for low ethylene production and slow softening in fruit. A microarray analysis to identify gene expression patterns associated with desirable apple fruit texture (firmness and crispness) in a segregating population is also in progress. Expression patterns and the potential role of four apple alcohol acyl transferase (AAT) gene family members and two ethylene biosynthesis genes (ACS1 and ACS3) were investigated between two apple cultivars with high (‘Golden Delicious’) and low (‘Granny Smith’) volatile ester production. Patterns of AAT gene expression were consistent with the volatile production dynamics for these two cultivars, although a detectable increase in expression of ACS1 lagged behind fruit ethylene production. NP306, Component 1, Problem D
Lipophilic coatings applied preharvest reduce lenticel breakdown of apples in storage.
Lenticel breakdown disorder (LB), prevalent on ‘Gala’ apples, usually appears poststorage as one or more round, darkened pits, centered on a lenticel, ranging in diameter from 1-8 mm. Though not visible at harvest or on unprocessed fruit after storage, symptoms are generally expressed 12-48 h after typical processing and packing. ARS scientists in Wenatchee, WA applied lipophilic formulations to whole trees at various dosages and timings and reduced LB symptom expression in stored fruit by as much as 20%, 35% and 70% in 2005, 2006 and 2007, respectively. Lipophilic treatments may cover microcracks to prevent moisture loss and desiccation-induced necrosis. National Program 306 Component I:Quality Characterization, Preservation and Enhancement; Problem Statement D:Preservation and/or Enhancement of Quality and Marketability.
Application of 1-MCP in water slows ripening of apple fruit during storage. Slowing apple ripening after harvest results in an extension of the period of marketability. Research conducted by the ARS scientists in the Physiology and Pathology of Tree Fruits Research Unit in Wenatchee, WA showed that by applying 1-methylcyclopropene, a gaseous inhibitor of apple ripening, in water proved to be an effective means to slow ‘Golden Delicious’ apple ripening to extend the marketability period. This is the first report of 1-MCP efficacy when applied in water and may allow development of additional delivery protocols that are applicable for smaller warehouses or growers that do not have facilities for storage room application of 1-MCP as a gas. National Program 306 Component I:Quality Characterization, Preservation and Enhancement; Problem Statement D:Preservation and/or Enhancement of Quality and Marketability.
5.Significant Activities that Support Special Target Populations
Contacts with growers, warehouse and university cooperative extension personnel regarding fruit development, storage protocols and physiological disorders on apples and pears occur frequently. Information provided is based on the expertise in this CRIS on current issues such as maturity and storability of newer cultivars, identification and development of storage disorders and methods for quality improvement. Published information is provided as well as general discussion in the area of interest. These interactions assist those seeking information who may not have received the most recent publications and provide public access to location researchers currently working on relevant issues faced by the industry. A dozen or more contacts per month from growers, quality control personnel, field staff, warehouse operators and those in closely associated industries is typical.
|Number of Non-Peer Reviewed Presentations and Proceedings||5|
Argenta, L.C., Fan, X., Mattheis, J.P. 2007. Responses of 'golden delicious' apples to 1-mcp applied in air or water. HortScience. 42:1651-1655.
Rudell Jr, D.R., Mattheis, J.P. 2008. Synergism Exists Between Ethylene and Methy Jasmonate in Artificial Light-Induced Pigment Enhancement of 'Fuji' Apple Fruit Peel. Postharvest Biology and Technology. (47): 136-140.
Rudell Jr, D.R., Mattheis, J.P., Curry, E.A. 2008. Pre-storage UV-White Light Irradiation Alters Apple Peel Metabolome. Journal of Agricultural and Food Chemistry. 56:1138-1147.
Mattheis, J.P., Rudell Jr, D.R. 2008. Diphenylamine Metabolism in 'Braeburn' Apples Stored under Conditions Conducive to Development of Internal Browning. Journal of Agricultural and Food Chemistry. 56:3381-3385.
Zhu, Y., Rudell Jr, D.R., Mattheis, J.P. 2008. Characterization of cultivar differences in alcohol acyltransferase and 1-aminocyclopropane-1carboxylate synthase gene expression and volatile compound emission during apple fruit maturation and ripening. Postharvest Biology and Technology 49:(3):330-339.