Papers by Daniel Manriquez
Journal of Agricultural and Food Chemistry, 2010
Contributed equally to the work. Mountain papaya (Vasconcellea pubescens) is a climacteric fruit ... more Contributed equally to the work. Mountain papaya (Vasconcellea pubescens) is a climacteric fruit that develops a strong and characteristic aroma during ripening. Esters are the main volatile compounds produced by the fruit, and most of them are dependent on ethylene. As esters are synthesized through alcohol acyltransferases (AAT), a full-length cDNA (VpAAT1) was isolated that displayed the characteristic motifs of most plant acyltransferases. The full-length cDNA sequence was cloned and expressed in yeasts, obtaining a functional enzyme with high AAT activity toward the formation of benzyl acetate. The transcript accumulation pattern provided by qPCR analysis showed that the VpAAT1 gene is expressed exclusively in fruit tissues and that a high level of transcripts is accumulated during ripening. The increase in VpAAT1 transcripts in fruit is coincident with the increase in AAT activity; transcript accumulation is induced by ethylene, and it is avoided by 1-methylcyclopropene (1-MCP) treatment. The data indicate that VpAAT1 is involved in aroma formation and that ethylene plays a major role in regulating its expression.
Acta Horticulturae, 2011
Ethylene plays an important role in coordinating the ripening process in climacteric fruit, inclu... more Ethylene plays an important role in coordinating the ripening process in climacteric fruit, including pears. Regarding 'Abate Fetel', despite having good storage potential, little information is available about the effect of ethylene inhibition (pre-and postharvest) in the development of quality attributes. Therefore, the main objective of this study was to evaluate the effect of two formulations of 1-methylcyclopropene (1-MCP), one applied preharvest (Harvista TM Technology) and the second one after harvest (SmartFresh TM). In order to develop a commercial strategy, including doses of both formulations, timing of application and storage potential, the trials were performed during three seasons in the same orchard:
V International Postharvest Symposium, 2005
Volatiles esters impart distinct characteristics to the fruit quality. 'Charentais' cantaloupe me... more Volatiles esters impart distinct characteristics to the fruit quality. 'Charentais' cantaloupe melon (Cucumis melo 'cantalupensis') is characterized by abundant sweetness and aromatic flavour. Plant alcohol acyl transferase (AAT) genes have been identified and shown to be involved in aromas production. Recently, two cDNAs (Cm-AAT 1 and Cm-AAT 2) putatively involved in the formation of aroma volatile esters have been isolated from melon fruit. Cm-AAT 1 protein exhibit alcohol acyl transferase activity while no such activity could be detected for Cm-AAT 2. Two new cDNAs (Cm-AAT 3 and Cm-AAT 4) have been isolated from melon fruit that showed 69% and 36% similarity, respectively, with Cm-AAT 1. The percentage similarity over the whole amino acid sequence between them is 34%. Cm-AAT 3 and Cm-AAT 4 show the highest similarity to the tobacco Nt-HSR201 protein and a rose alcohol acyltransferase Rh-AAT 1 , respectively. All Cm-AATs genes, share three conserved regions common to the BAHD acyltransferase gene superfamily. Heterologous expression in yeast revealed that some of the encoded proteins have a wide range of specificity while others are specific to a narrow range of substrates.
V International Postharvest Symposium, 2005
The sensory quality of fruit has become a major criterion in making the purchasing decision by co... more The sensory quality of fruit has become a major criterion in making the purchasing decision by consumers. Breeding programs have mainly been directed, from the post-harvest stand point, towards improving shelf-life. Chance seedlings or mutants with improved agronomic traits and/or extended shelf-life have been used for introgressing the long shelf-life character and eventually improved sensory quality traits in commercial genotypes of apple, melon or tomato. Because the plant hormone ethylene plays a central role in both storability and ripening of climacteric fruit, the generation by biotechnology of ethylene-inhibited fruit has offered a powerful tool to better understand, at the molecular and genetic level, the interrelations between storability and sensory quality. In the melon, inhibition of ethylene synthesis results is a strong inhibition of the synthesis of aroma volatiles while the accumulation of sugars is not affected or is even improved. The softening of the flesh is strongly affected but not abolished. Mid or long shelf-life melons generated by classical breeding present the same behavior. The generation of recombinant inbred lines by crossing a typical climacteric melon (Cantaloupe Charentais of the cantalupensis group) with a non climacteric melon (PI161375 of the agrestis chinensis group) allowed to demonstrate that the climacteric character is conferred by 2 duplicated loci only, which are of great importance for the regulation of storability and sensory quality. Due to the importance of aroma volatiles in sensory quality and to the strong negative correlation between aroma production and ethylene synthesis, we have developed a research program aimed at isolating genes involved in the synthesis of aroma volatiles. We will report on the recent advances in the field with special emphasis on the characterization of genes responsible for the synthesis of esters, a family of compounds crucial for the flavor of many fruit.
Acta Horticulturae, 2007
Traditional Charentais melons have a typical climacteric behavior with ethylene playing a major r... more Traditional Charentais melons have a typical climacteric behavior with ethylene playing a major role in the regulation of the ripening process. Genetic studies using climacteric and non-climacteric types of Cucumis melo demonstrated that the climacteric character is dominant and conferred by 2 duplicated loci only which are of great importance for the regulation of storability and sensory quality. Commercial varieties of Charentais melon with long shelf-life have been generated, some of them by crossing with a non-ripening Charentais genotype (Vauclusien). The introduction of the long shelf-life character resulted in undesirable loss of aroma volatiles production. The inhibition of ethylene synthesis by knocking-down ACC oxidase gene expression has been achieved in Charentais melon. It results is a strong inhibition of the synthesis of aroma volatiles while the accumulation of sugars is not affected or is even improved and the softening of the flesh is strongly affected but not abolished. It was also demonstrated that ethylene-inhibited fruit exhibited better resistance to chilling injury. Due to the importance of aroma volatiles in sensory quality and to the strong negative correlation between aroma production and ethylene synthesis, we have developed a research program aimed at isolating genes involved in the synthesis of volatile esters, compounds that are essential for the flavor of Cantaloupe melons. We report here on the recent advances in the field with special emphasis on the characterization of two families of genes encoding aldehyde reductases and alcohol acyl transferases.
VII International Symposium on Kiwifruit, 2011
A major challenge during long term storage of kiwifruit is the maintenance of fruit firmness, whi... more A major challenge during long term storage of kiwifruit is the maintenance of fruit firmness, which could be seriously affected by ethylene levels due to contamination events. In order to reduce ethylene effects during storage several tools are commercially used, including air ventilation and ethylene scrubbers such as catalytic converters and potassium permanganate. The ethylene antagonist 1methylcyclopropene (1-MCP) has shown benefits in extending kiwifruit storage life, but its effect has not been tested under ethylene contamination conditions, which was the main objective of this work. To perform the assay, kiwifruit applied with 1 ppm 1-MCP for 24 h immediately after harvest were stored for 90 days at 0°C. Ethylene contamination was performed with 400 ppb of ethylene applied for 72 h at four times during storage, i.e., 0, 30, 60 and 90 days. As already reported, fruit applied with 1-MCP remained firmer after storage than untreated fruit. In terms of contamination, ethylene applied in the first 30 days of storage was the most detrimental in inducing fruit softening. This effect on firmness was evident after 60 days of storage when half the fruit not treated with 1-MCP was at a firmness less than 3 lbf. In contrast, less than 10% of the fruit treated with 1-MCP was under this commercial threshold. No other quality attributes were affected by 1-MCP application or ethylene contamination. Therefore, 1-MCP could be considered as an effective tool for reducing the negative effects of ethylene contamination during storage.
VIII International Controlled Atmosphere Research Conference, 2003
Export of Chilean cherries to the Japanese market has been just authorized provided fruit is fumi... more Export of Chilean cherries to the Japanese market has been just authorized provided fruit is fumigated with methyl bromide to eliminate potential fruit infestation with codling moth. Research in the 2000/2001 season was carried out at INIA to find controlled atmosphere (CA) treatments that could alleviate negative effects of the fumigation procedure. Quality losses caused by fumigation treatment were defined. Furthermore, fumigated and non-fumigated Bing cherries were subjected to different combinations of CO 2 /O 2 in 2 separate trials using an automated system (Kronenberger Systemtechnik, Germany). Levels of CO 2 ranged from 0 to 30 kPa combined with O 2 at levels between 0 and 21 kPa. Fruit were cold stored with periodic evaluations being performed directly after cold storage and after 2 days of shelf life at 20ºC. Fruit color, firmness, respiration rate, incidence of disorders and decay were measured. Fumigation with methyl bromide negatively affected fruit and stem appearance. Despite the ample range of gas levels assayed, CA treatments were not able to markedly influence quality aspects with the exception of decay being significantly reduced. However, fruit showed a remarkable tolerance towards high CO 2 and moderate low O 2 levels.
IV International Symposium on Kiwifruit, 1999
IV International Cherry Symposium, 2005
Prohexadione-Ca (P-Ca, BAS 125 11 W), a gibberellin biosynthesis inhibitor, was applied to mature... more Prohexadione-Ca (P-Ca, BAS 125 11 W), a gibberellin biosynthesis inhibitor, was applied to mature, vigorous `Bing' cherry trees at 3 concentrations (75, 150 or 300 mg a.i./L). Treatments were applied by whole-tree sprays in the autumn (postharvest), with or without a follow-up treatment during the subsequent spring (preharvest) or autumn (one year later), with an untreated control. There were no effects of autumn-applied treatments on reduction of vegetative growth in either the season of application or the next year. Spring-applied P-Ca treatments significantly reduced vegetative growth as measured by shoot length. The reduction in shoot length, both in lateral and terminal positions, was proportional to the dosage applied. Further work is required to formulate definitive recommendations for Chilean conditions, as no measurements on fruit quality were conducted; however, this bioregulator appears promising for in achieving growth control under vigorous conditions typical of Chilean cherry orchards.
Advances in Plant Ethylene Research, 2007
... de l'Agrobiopole, BP 32607, F-31326 Castanet-Tolosan A. Ramina et al. ... Both also ... more ... de l'Agrobiopole, BP 32607, F-31326 Castanet-Tolosan A. Ramina et al. ... Both also show strong preference for ali-phatic aldehydes. Cm-ADH1 is capable of reducing branched aldehydes such as 3-methylbutyraldehyde, whereas Cm-ADH2 cannot. ...
Postharvest Biology and Technology, 2012
Apricots are climacteric fruits with a high susceptibility to flesh softening and loss of flavor ... more Apricots are climacteric fruits with a high susceptibility to flesh softening and loss of flavor during postharvest storage, and most of the ripening processes are regulated by ethylene, which also has an effect on its own biosynthesis. To understand this process in apricot, inhibition of ethylene biosynthesis and perception was performed for studying key genes involved in the ethylene biosynthetic pathway. Apricots, cv. "Patterson", were harvested with yellow-green ground color and immediately treated with either the ethylene perception inhibitor 1-methyl cyclopropene (1-MCP) at 10 L L −1 or the ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG) at 1 g L −1. After treatment, quality and physiological attributes such as firmness, color, total soluble solids, acidity, fruit weight, ethylene production and respiration rates were evaluated every 2 d until they ripened at 20 • C. Gene expression analysis was performed by quantitative polymerase chain reaction (qPCR). Both ethylene inhibitors were effective in reducing ethylene production, respiration rate and fruit softening. Three 1-aminocyclopropane-1carboxylic-acid synthase (ACS) genes were characterized, but only the expression of ACS2 was highly reduced by ethylene inhibition, suggesting a key role in ethylene synthesis at ripening. Contrarily, ACS1 and ACS3 showed a higher expression under ethylene inhibition suggesting that the corresponding genes are individually regulated in a specific mode as observed in other climacteric fruits. Finally, changes in 1-aminocyclopropane-1-carboxylic-acid oxidase genes did not show a consistent pattern of ethylene modulation.
Advances in Botanical Research, 2009
Flavor composition has been defined as a complex attribute of quality, in which the mix of sugars... more Flavor composition has been defined as a complex attribute of quality, in which the mix of sugars, acids, and volatiles play a primary role. In addition to the four basic flavors (sweet, sour, salty, and bitter) that humans can recognize in fruits and vegetables, aroma has an important influence on the final consumer acceptance of the commodity. Fruit aroma is
Postharvest Biology and Technology, 2014
ABSTRACT Flavor is one of the most important attributes of fresh fruit for the consumer, and is a... more ABSTRACT Flavor is one of the most important attributes of fresh fruit for the consumer, and is affected by several factors, including genotype, maturity stage, and environmental conditions. Flavor-related metabolites were characterized in two important cherimoya varieties, cv. Concha Lisa and cv. Bronceada, during fruit ripening. The most important sugars present were glucose, fructose and sucrose, and only fructose and glucose increased during ripening. The most important acids were tartaric, malic and citric acids, and all increased as ripening progressed. Overall aroma profile was mainly determined by esters and terpenes in both varieties. Ester compounds such as ethyl hexanoate, butyl butyrate and hexyl propanoate increased during ripening. The activity of alcohol acyl transferase also increased during fruit ripening concomitant with ester accumulation. Terpenes, such as α and β-pinene, showed a reduction during ripening, whereas others, such as myrcene and limonene, increased.
Plant Molecular Biology, 2006
Alcohol dehydrogenases (ADH) participate in the biosynthetic pathway of aroma volatiles in fruit ... more Alcohol dehydrogenases (ADH) participate in the biosynthetic pathway of aroma volatiles in fruit by interconverting aldehydes to alcohols and providing substrates for the formation of esters. Two highly divergent ADH genes (15% identity at the amino acid level) of Cantaloupe Charentais melon (Cucumis melo var. Cantalupensis) have been isolated. Cm-ADH1 belongs to the medium-chain zinc-binding type of ADHs and is highly similar to all ADH genes expressed in fruit isolated so far. Cm-ADH2 belongs to the short-chain type of ADHs. The two encoded proteins are enzymatically active upon expression in yeast. Cm-ADH1 has strong preference for NAPDH as a co-factor, whereas Cm-ADH2 preferentially uses NADH. Both Cm-ADH proteins are much more active as reductases with K m s 10-20 times lower for the conversion of aldehydes to alcohols than for the dehydrogenation of alcohols to aldehydes. They both show strong preference for aliphatic aldehydes but Cm-ADH1 is capable of reducing branched aldehydes such as 3-methylbutyraldehyde, whereas Cm-ADH2 cannot. Both Cm-ADH genes are expressed specifically in fruit and up-regulated during ripening. Gene expression as well as total ADH activity are strongly inhibited in antisense ACC oxidase melons and in melon fruit treated with the ethylene antagonist 1-methyl-cyclopropene (1-MCP), indicating a positive regulation by ethylene. These data suggest that each of the Cm-ADH protein plays a specific role in the regulation of aroma biosynthesis in melon fruit. Keywords Alcohol dehydrogenase/aldehyde reductase AE Aroma volatiles AE Ethylene AE Fruit ripening AE Mediumand short-chain ADH AE Melon Daniel Manríquez and Islam El-Sharkawy contributed equally to the work. Accession numbers for Cm-ADH1 (ABC02081), and Cm-ADH2 (ABC02082).
Journal of Agricultural and Food Chemistry, 2007
Alcohol acyltransferases (AAT) play a key role in the biosynthesis of ester aroma volatiles in fr... more Alcohol acyltransferases (AAT) play a key role in the biosynthesis of ester aroma volatiles in fruit. Three ripening-specific recombinant AATs of cantaloupe Charentais melon fruit (Cm-AAT1, Cm-AAT3, and Cm-AAT4) are capable of synthesizing thioether esters with Cm-AAT1 being by far the most active. All proteins, as well as AAT(s) extracted from melon fruit, are active as tetramers of around 200 kDa. Kinetic analysis demonstrated that CoA-SH, a product of the reaction, is an activator at low concentrations and an inhibitor at higher concentrations. This was confirmed by the addition of phosphotransacetylase at various concentrations, capable of modulating the level of CoA-SH in the reaction medium. Site-directed mutagenesis of some amino acids that were specific to the Cm-AAT sequences into amino acids that were consensus to other characterized AATs greatly affected the selectivity of the original protein and the number of esters produced.
Chilean journal of agricultural research, 2011
Flavor composition has been defined as a complex attribute of fruit quality, in which the mix of ... more Flavor composition has been defined as a complex attribute of fruit quality, in which the mix of sugars, acids and volatiles play a primary role. In table grapes (Vitis vinifera L.), sweetness and sourness are the most important flavor attributes for fresh consumption. However, most of the studies available have been performed on wine grapes, which are grown, cultured and processed differently to table grapes. Therefore, the objective of this work was to characterize the changes in sugars and organic acids during the development of 'Thompson Seedless', 'Red Globe' and 'Crimson Seedless' grown under the same agroclimatic conditions. Each variety was sampled weekly from 2 wk before véraison until commercial harvest. Sugars and organic acids were quantified by high performance liquid chromatography (HPLC) equipped with an evaporative light scattering detector (ELSD) and ultra violet detector, respectively. The ranges of acid and sugars concentrations found in grapes were as follows: tartaric acid, 1.28-7.45 g L-1 ; malic acid, 0.38-29.92 g L-1 , citric acid traces-1.03 g L-1 ; fructose, 0.15-8.74 g (sugar) 100 g(grape)-1 ; glucose, 0.19-8.71 g (sugar) 100 g(grape)-1 and sucrose 0.02-0.91 g (sugar) 100 g(grape)-1. Among sugars, glucose was the most abundant one in early stages and then it decreased until the harvest period, when the amount of fructose and glucose converged to an average of 47% for each sugar. Despite organic acids reaching steady levels 3-4 wk before commercial harvest, there were important differences in the organic acid profiles among varieties, with 'Thompson Seedless' showing the lowest tartaric/malic acid ratio of 1.19. These differences are an important aspect in terms of overall flavor.
Advances in Botanical …, 2009
Flavor composition has been defined as a complex attribute of quality, in which the mix of sugars... more Flavor composition has been defined as a complex attribute of quality, in which the mix of sugars, acids, and volatiles play a primary role. In addition to the four basic flavors (sweet, sour, salty, and bitter) that humans can recognize in fruits and vegetables, aroma ...
Plant Molecular Biology, 2005
Volatile esters, a major class of compounds contributing to the aroma of many fruit, are synthesi... more Volatile esters, a major class of compounds contributing to the aroma of many fruit, are synthesized by alcohol acyl-transferases (AAT). We demonstrate here that, in Charentais melon (Cucumis melo var. cantalupensis), AAT are encoded by a gene family of at least four members with amino acid identity ranging from 84% (Cm-AAT1/Cm-AAT2) and 58% (Cm-AAT1/Cm-AAT3) to only 22% (Cm-AAT1/Cm-AAT4). All encoded proteins, except Cm-AAT2, were enzymatically active upon expression in yeast and show differential substrate preferences. Cm-AAT1 protein produces a wide range of short and long-chain acyl esters but has strong preference for the formation of E-2-hexenyl acetate and hexyl hexanoate. Cm-AAT3 also accepts a wide range of substrates but with very strong preference for producing benzyl acetate. Cm-AAT4 is almost exclusively devoted to the formation of acetates, with strong preference for cinnamoyl acetate. Site directed mutagenesis demonstrated that the failure of Cm-AAT2 to produce volatile esters is related to the presence of a 268-alanine residue instead of threonine as in all active AAT proteins. Mutating 268-A into 268-T of Cm-AAT2 restored enzyme activity, while mutating 268-T into 268-A abolished activity of Cm-AAT1. Activities of all three proteins measured with the prefered substrates sharply increase during fruit ripening. The expression of all Cm-AAT genes is up-regulated during ripening and inhibited in antisense ACC oxidase melons and in fruit treated with the ethylene antagonist 1-methylcyclopropene (1-MCP), indicating a positive regulation by ethylene. The data presented in this work suggest that the multiplicity of AAT genes accounts for the great diversity of esters formed in melon.
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Papers by Daniel Manriquez