9/22/2015. Points to cover. As we all know, there are many factors. The pioneer work in the area of fresh-cut

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1 Points to cover Elucidating the Wound Signal Mechanism in Fresh cut Produce: Scientific Implications and Opportunities for Practical Applications and Novel Technologies Luis Cisneros-Zevallos, Ph.D. Dept. of Horticultural Sciences Food Science Graduate Program Molecular & Environmental Plant Sciences Program Plant Bioactives & Bioprocessing Research La Texas A&M University, College Station Background on postharvest stresses Understanding mechanisms and its importance Implications/technologies used Examples from our group The pioneer work in the area of fresh-cut Dr Mikal Saltveit Dr Francisco Tomas Bareran Dr Adel Kader Dr Mikal Saltveit Through his work in estalishing the iochemical and physiological asis of the wound response. he set the asis to understand the signaling mechanisms As we all know, there are many factors Market -market we are targeting Quality characteristics -flavor, color, texture, rowning Health promoting properties -composition, functional property, ioactivity Technologies used -need to understand mechanisms to make Impacts!!!...ut many gaps!!! Lets explore some ideas.. The 1MPC story is a good example of mechanism having an Impact The use of 1 MCP had a dramatic effect in Postharvest Perhaps the most important in the past few years 1MCP inds to receptors and locks ethylene action it stops everything from the real eginning Knowledge of the mechanism involved allowed a novel technology it reduced a gap etween asic science and application why not do the same for other events??? Actual status of research in Postharvest Stress Signal Gene expression Protein expression Physiology/iochemistry Study efforts <0.5% 4% Quality traits 95% asic applied Many gaps etween mechanisms and practical applications!!!! 1

2 Post-harvest stresses Temperature Water Gas Radiation (gamma, UV) Chemical Mechanical (wounding) Gravitational Post-harvest technologies Temperature management Controlled atmospheres Modified atmospheres Chemical treatments Fresh-cut processing Increase in antioxidant activity Phenolics of wounded carrots after 4 days Mechanism for wounding.. W ounding Intensity (Area/W t) Phenolics (mg Chlorogenic Acid/100 g) 250 Navajo a Legend 200 Choctaw a c Wounding Intensity (cm 2 /g) Different letters show significant difference (Tukey, P<0.05) Control (0 cm 2 /g) Slices (4.2 cm 2 /g) Pies (6.0 cm 2 /g) Shreds (23.5 cm 2 /g) AOX ( g Trolox/g tissue) AOX of wounded carrots after 4 days 2000 Navajo a 1500 Legend Choctaw Surjadinata and Cisneros-Zevallos, 2012, Food Chem 0 a c Wounding Intensity (cm 2 /g) Wounding effects on different types of produce Lettuce, celery, onions, carrots, jicama, ell peppers, asparagus, caage, apples, tomatoes, nectarines, radishes, potatoes, pears Changes in -activity of different fresh produce after wounding and storage at 15 ºC for 2 days. -ACTIVITY [moles/(h.g)] WHOLE WOUNDED Potato 0.02 ± ± 0.1 Sweetpotato 0.02 ± ± 0.04 Celery 0.02 ± ± 0.04 White Caage 0.05 ± ± 0.4 Parsnips 0.05 ± ± 0.2 Zucchini 0.06 ± ± 0.2 Carrot 0.06 ± ± 0.2 Lettuce 0.07 ± ± 0.1 Radish 0.07 ± ± 0.1 Red Caage 0.08 ± ± 0.5 a Data represents the MEAN ± SD (n = 9). 2

3 Changes in reduced ascoric acid content of different fresh Produce after wounding and storage at 15 ºC for 2 days. ASCORBIC ACID [mg/kg of tissue] WHOLE WOUNDED % CHANGE c Lettuce Not detected Not detected Not detected Carrot 16.7 ± ± % Parsnips 29.5 ± ± % Celery 33.6 ± ± % Potato 50.0 ± ± % Zucchini 125 ± ± % Sweetpotato 162 ± ± 21 12% * Radish 225 ± ± 14 7% * White Caage 350 ± ± 23 11% Red Caage 599 ± ± % * Increase in antioxidant activity depends on the type of produce a Data represents the MEAN ± SD (n = 9). Data expressed as mg ascoric acid per kg of tissue. c Data with - sign represents a decrease, while a + sign represents an increase in ascoric acid content. * Non-significant changes after wounding (P > 0.05). Antioxidant systems Phenolic acids, Flavonoids Stress induced activation of phenylpropanoid metaolism Ascoric acid p Readily availale Kd Phenolic Physical nature Chemical nature c Formation and polymerization o d Water stress k, l WOUND HEALING m Lignin i Polymerization n Suerin j Oxidation products h Ks Aiotic stresses REACTIVE OXYGEN SPECIES () mrna phenylalanine ammonia lyase () gene protein activity WOUNDING Wound signal expression a mrna transcription de novo synthesis - activity f PHENOLIC BIOSYNTHESIS g Categories used to classify the clones of genes otained in the sutracted cdna lirary Metaolic Function Stress signaling molecules Caron source Phenolics metaolism Other disease and stress response genes Other metaolic genes Genes involved Ethylene iosynthesis genes Jasmonic acid iosynthesis genes Reactive oxygen species iosynthesis and modulation/detoxification genes Oligosaccharides iosynthesis genes Glycolisis and pentose phosphate pathway genes Shikimate pathway genes Aromatic amino acid iosynthesis genes Hydroxycinnamic acids iosynthesis genes Flavonoids iosynthesis genes Coumarin phytoalexins iosynthesis genes Lignin iosynthesis genes Jacoo Velazquez et al., J Agr Food Chem Unidentified function genes Novel genes 3

4 Cross talk among signals early response Late response Jacoo Velazquez et al., Scientific Reports Jacoo Velazquez et al., Scientific Reports Wound (Cisneros-Zevallos et al., Modified from Saltveit, 1997) primary signal Heat secondary signal Respiration Ethylene Phenolic metaolism Reduced Carohydrates Oragnic acids Ascoric acid Poor flavor Ripening Softening Browning PPO Suerin Phenolic lignin Wound healing Periderm Cell division Mechanism for wounding and dehydration.. Cisneros-Zevallos et a., Handook of Plant and Crop Physiology toughening Wounding Immediate wound response NADPH oxidase O. 2 SOD receptor H 2 [Ca 2+ ] cyt Water stress ABA Late wound response NADPH oxidase. [Ca 2+ ] cyt SOD H 2 Mitochondrial respiration Activation of primary and secondary plant metaolism Mitochondrial respiration Activation of primary and secondary plant metaolism Wounding Becerra et al., Frontiers Plant Science Becerra et al., Frontiers Plant Science 4

5 High levels of shikimic acid from Star anise Plants as iofactories: High levels of shikimic acid and phenolic Tamiflu Intermediate compound efore the phenolic metaolism Jacoo et al, J Agri Food Chem Summary. understanding market needs is important understanding quality needs and traits is important understanding health promoting properties is important BUT understanding signals and mechanism is a MUST. This will allow us to change, create and design technologies and even propose targets for selecting, reeding and transforming plants Questions? Research Team: Conacyt Tamu grant Laex USDA funding Dr. Daniel Jacoo Velazquez, TEC Monterrey Dr. Ricardo Elesao Alves, EMBRAPA 5