Postharvest Treatment with Abscisic Acid Alleviates Chilling Injury in Zucchini Fruit by Regulating Phenolic Metabolism and Non-Enzymatic Antioxidant System.

Reports show that phytohormone abscisic acid (ABA) is involved in reducing zucchini postharvest chilling injury. During the storage of harvested fruit at low temperatures, chilling injury symptoms were associated with cell damage through the production of reactive oxygen species. In this work, we have studied the importance of different non-enzymatic antioxidants on tolerance to cold stress in zucchini fruit treated with ABA. The application of ABA increases the antioxidant capacity of zucchini fruit during storage through the accumulation of ascorbate, carotenoids and polyphenolic compounds. The quantification of specific phenols was performed by UPLC/MS-MS, observing that exogenous ABA mainly activated the production of flavonoids. The rise in all these non-enzymatic antioxidants due to ABA correlates with a reduction in oxidative stress in treated fruit during cold stress. The results showed that the ABA mainly induces antioxidant metabolism during the first day of exposure to low temperatures, and this response is key to avoiding the occurrence of chilling injury. This work suggests an important protective role of non-enzymatic antioxidants and polyphenolic metabolism in the prevention of chilling injury in zucchini fruit.

The ethylene receptor mutation etr2b reveals crosstalk between ethylene and ABA in the control of Cucurbita pepo germination.

The enhanced salt tolerance of squash ethylene-insensitive mutants during germination and early stages of seedling development suggested that abscisic acid (ABA) could mediate this tolerance. To gain insight into the crosstalk between ethylene and ABA in seed germination, the germination rate and early seedling growth of wild type (WT) and ethylene-insensitive etr2b mutant were compared in seeds germinated under water and exogenous ABA treatment. The etr2b seeds germinated earlier than WT under both water and ABA, and the effect of ABA on radicle length and seedling growth of etr2b was lower than in WT, indicating that etr2b is also insensitive to ABA. The comparison of ABA and ethylene contents and ABA and ethylene gene expression profiles in WT and etr2b dry and imbibed seeds in either water, NaCl or ABA demonstrated a clear crosstalk between ethylene and ABA in germination. The expression profiles of ethylene genes in WT and etr2b indicated that the role of ethylene in seed germination does not appear to follow the canonical ethylene signaling pathway. Instead, etr2b reduces ABA content during formation of the seeds (dry seeds) and in response to seed imbibition and germination, which means diminished dormancy in the ethylene mutant. The etr2b mutation downregulated the expression of ABA biosynthesis and signaling genes during germination, demonstrating the positive role of ethylene receptor gene CpETR2B on seed germination and early seedling growth in squash is mediated by ABA. The reduced effect of exogenous ABA on ethylene production and ethylene gene expression in etr2b seeds suggests that this regulation is also dependent on ethylene.

Jasmonate-deficient mutant lox3a reveals crosstalk between jasmonate and ethylene in the differential regulation of male and female flower opening and early fruit development in Cucurbita pepo.

Jasmonate (JA) has been found to be a relevant hormone in floral development in numerous species, but its function in cucurbit floral development and sex determination is unknown. Crosstalk between JA and ethylene (ET) in the differential regulation of male and female floral development was investigated by using the novel JA-deficient mutant lox3a, and the ET-deficient and -insensitive mutants, aco1a and etr2b, respectively, of Cucurbita pepo. The lox3a mutation suppresses male and female flower opening and induces the development of parthenocarpic fruit. A bulked-segregant analysis coupled with whole genome sequencing and fine mapping approach allowed the identification of lox3a mutation in CpLOX3A, a LIPOXYGENASE gene involved in JA biosynthesis. The reduced JA content and expression of JA-signalling genes in male and female flowers of lox3a, and the rescue of lox3a phenotype by external application of methyl jasmonate (MeJA), demonstrated that JA controls petal elongation and flower opening, as well as fruit abortion in the absence of fertilization. JA also rescued the phenotype of ET mutants aco1a and etr2b, which are both specifically defective in female flower opening and fruit abortion. ET, the sex determining hormone of cucurbits, is induced in female flowers towards anthesis, activating JA production and promoting the aperture of the female flower, and the abortion of the unfertilized ovary. Given the close association between flower closure and parthenocarpic fruit development, we propose that flower opening can act as a switch that triggers fruit set and development in fertilized ovaries, but may alternatively induce the abortion of the unfertilized ovary. Both ET and JA from mature and senescent petals can serve as remote signals that determine the alternative development of the ovary and fruit.

The Ethylene Biosynthesis Gene CpACO1A: A New Player in the Regulation of Sex Determination and Female Flower Development in Cucurbita pepo.

A methanesulfonate-generated mutant has been identified in Cucurbita pepo that alters sex determination. The mutation converts female into hermaphrodite flowers and disrupts the growth rate and maturation of petals and carpels, delaying female flower opening, and promoting the growth rate of ovaries and the parthenocarpic development of the fruit. Whole-genome resequencing allowed identification of the causal mutation of the phenotypes as a missense mutation in the coding region of CpACO1A, which encodes for a type I ACO enzyme that shares a high identity with Cucumis sativus CsACO3 and Cucumis melo CmACO1. The so-called aco1a reduced ACO1 activity and ethylene production in the different organs where the gene is expressed, and reduced ethylene sensitivity in flowers. Other sex-determining genes, such as CpACO2B, CpACS11A, and CpACS27A, were differentially expressed in the mutant, indicating that ethylene provided by CpACO1A but also the transcriptional regulation of CpACO1A, CpACO2B, CpACS11A, and CpACS27A are responsible for determining the fate of the floral meristem toward a female flower, promoting the development of carpels and arresting the development of stamens. The positive regulation of ethylene on petal maturation and flower opening can be mediated by inducing the biosynthesis of JA, while its negative control on ovary growth and fruit set could be mediated by its repressive effect on IAA biosynthesis.

Two androecious mutations reveal the crucial role of ethylene receptors in the initiation of female flower development in Cucurbita pepo.

Ethylene is the key regulator of sex determination in monoecious species of the family Cucurbitaceae. This hormone determines which individual floral meristems develop as female or male flowers and the female flowering transition. The sex determination genes discovered so far code for ethylene biosynthesis enzymes, but little is known about the importance of ethylene signaling components. In this paper we characterize two novel ethylene-insensitive mutations (etr1a-1 and etr1b) which block the female flowering transition of Cucurbita pepo; this makes plants produce male flowers indefinitely (androecy). Two missense mutations in the ethylene-binding domain of the ethylene receptors CpETR1A or CpETR1B were identified as the causal mutations of these phenotypes by using whole-genome resequencing. The distinctive phenotypes of single and double mutants for four etr mutations have demonstrated that the final level of ethylene insensitivity depends upon the strength and dosage of mutant alleles for at least three cooperating ETR genes, and that the level of ethylene insensitivity determines the final sex phenotype of the plant. The sex phenotype ranges from monoecy in ethylene-sensitive wild-type plants to androecy in the strongest ethylene-insensitive ones, via andromonoecy in partially ethylene-insensitive plants. The induction of female flowering transition was found to be associated with upregulation of CpACS11, CpACO2 and CpACS27, three ethylene biosynthesis genes required for female flower development. A model is proposed herein, integrating both ethylene biosynthesis and receptor genes into the genetic network which regulates sex determination in C. pepo.

The ethylene receptors CpETR1A and CpETR2B cooperate in the control of sex determination in Cucurbita pepo.

High-throughput screening of an ethyl methanesulfonate-generated mutant collection of Cucurbita pepo using the ethylene triple-response test resulted in the identification of two semi-dominant ethylene-insensitive mutants: etr1a and etr2b. Both mutations altered sex determination mechanisms, promoting conversion of female into bisexual or hermaphrodite flowers, and monoecy into andromonoecy, thereby delaying the transition to female flowering and reducing the number of pistillate flowers per plant. The mutations also altered the growth rate and maturity of petals and carpels in pistillate flowers, lengthening the time required for flowers to reach anthesis, as well as stimulating the growth rate of ovaries and the parthenocarpic development of fruits. Whole-genome sequencing allowed identification of the causal mutation of the phenotypes as two missense mutations in the coding region of CpETR1A and CpETR2B, each one corresponding to one of the duplicates of ethylene receptor genes highly homologous to Arabidopsis ETR1 and ETR2. The phenotypes of homozygous and heterozygous single- and double-mutant plants indicated that the two ethylene receptors cooperate in the control of the ethylene response. The level of ethylene insensitivity, which was determined by the strength of each mutant allele and the dose of wild-type and mutant etr1a and etr2b alleles, correlated with the degree of phenotypic changes in the mutants.

Exogenous γ-aminobutyric acid treatment improves the cold tolerance of zucchini fruit during postharvest storage.

This work examines the effect of a treatment with 1 mM of γ-aminobutyric acid (GABA) on zucchini fruit during postharvest cold storage. Specifically, the effect of GABA on postharvest quality was measured, as well as its implication in the GABA shunt and other related metabolic pathways. The treatments were performed in Sinatra, a variety of zucchini highly sensitive to low-temperature storage. The application of GABA improved the quality of zucchini fruit stored at 4 °C, with a reduction of chilling-injury index, weight loss, and cell death, as well as a lower rate of electrolyte leakage. GABA content was significantly higher in the treated fruit than in the control fruit at all times analyzed. At the end of the storage period, GABA-treated fruit had higher contents of both proline and putrescine. The catabolism of this polyamine was not affected by exogenous GABA. Also, over the long term, the treatment induced the GABA shunt by increasing the activities of the enzymes GABA transaminase (GABA-T) and glutamate decarboxylase (GAD). GABA-treated fruit contained higher levels of fumarate and malate than did non-treated fruit, as well as higher ATP and NADH contents. These results imply that the GABA shunt is involved in providing metabolites to produce energy, reduce power, and help the fruit to cope with cold stress over the long term.

Recomendaciones de rehabilitación en el paciente quemado: revisión de literatura / Recomendações de reabilitação para paciente queimado: revisão da literatura / Rehabilitation recommendations in the burn patient: literature review

OBJETIVO: Realizar una revisión bibliográfica acerca de la rehabilitación en el paciente quemado, sintetizando las recomendaciones expuestas por los documentos de consenso internacionales y la bibliografía reciente. Además, exponemos la manera en que estas recomendaciones se han aplicado en la Unidad de Grandes Quemados del Hospital La Fe, en forma de un protocolo multidisciplinar de rehabilitación intensiva. MÉTODO: Se realizó una búsqueda bibliográfica de la literatura existente y los consensos internacionales centrados en el ámbito de la rehabilitación en el paciente quemado. Seguidamente, se relata la forma en que estas recomendaciones fueron implementadas en la Unidad de Grandes Quemados del Hospital La Fe de Valencia; en forma de un protocolo de rehabilitación intensivo y multidisciplinar. RESULTADOS: La bibliografía revisada refuerza los argumentos en favor del desarrollo y aplicación de protocolos de rehabilitación intensiva en las unidades de quemados para la mejora de los resultados funcionales de los pacientes. La experiencia en nuestra unidad en la cual se aplica un protocolo de este tipo coincide con los buenos resultados reportados. CONCLUSIONES: La aplicación precoz de una terapia rehabilitadora intensiva resulta clave a la hora de prevenir y tratar las posibles complicaciones funcionales y secuelas producidas por las quemaduras. Este tratamiento rehabilitador interdisciplinar se ha de centrar en la prevención de problemas a largo plazo, como las contracturas, la cicatrización anómala, deformidades, atrofia muscular, limitación de movilidad y otros problemas que merman la función física. Su utilización en cualquier unidad de quemados, permitirá optimizar los resultados funcionales de nuestros pacientes.(AU)

Objetivo: Realizar uma revisão da literatura científica sobre a reabilitação do paciente queimado, resumindo as recomendações estabelecidas por documentos de consenso internacional e na literatura recente. Além disso, apresentamos como essas recomendações foram implementadas na Unidade de Grandes Queimados do Hospital La Fe, na forma de um protocolo de reabilitação intensivo multidisciplinar. Método: Pesquisa bibliográfica da literatura e do consenso internacional existente centrado no campo da reabilitação no paciente queimado. Foi relatado como as recomendações internacionais foram implementadas para a prática dentro da unidade para atendimento ao grande queimado, no Hospital La Fe, no formato de um protocolo de reabilitação intensivo multidisciplinar. Resultados: A literatura existente reforça o desenvolvimento e implementação de protocolos de reabilitação intensiva em unidades de queimados para melhorar os resultados funcionais dos pacientes. A experiência em nossa unidade, em que esse tipo de protocolo é aplicado, corresponde aos bons resultados descritos na literatura. Conclusões: A aplicação antecipada de terapia de reabilitação intensiva é fundamental para a prevenção e tratamento de complicações e possíveis consequências funcionais causadas por queimaduras. Este tratamento interdisciplinar de reabilitação tem de se concentrar na prevenção de problemas de longo prazo, tais como contraturas, cicatrizes anormais, deformidades, atrofia muscular, dificuldade de locomoção e outros problemas que prejudicam a função física. Seu uso em qualquer unidade de queimados irá otimizar os resultados funcionais dos nossos pacientes.(AU)

ABSTRACT: OBJECTIVE: To perform a bibliographic review about rehabilitation of the burn patient, summarizing recommendations provided by international consensus documents and the most recent evidence. Moreover, we present the method in which this recommendations have been applied to the Great Burns Unit of the Hospital La Fe, in the format of a interdisciplinary intensive rehabilitation protocol. METHOD: A bibliographic search was performed among existent literature and international consensus documents focused on the field of burn patient rehabilitation. Following, the way in which this recommendations were applied at the Great Burns Unit of the Hospital La Fe of Valencia are presented in the shape of an intensive and multidisciplinar rehabilitation protocol. RESULTS: Reviewed bibliography supports the development and application of intensive rehabilitation protocols in burn units for the improvement of the functional results of their patients. The experience in our unit in which this sort of protocol is applied, matches the good results described in literature. CONCLUSIONS: Early intensive rehabilitation therapy is a key stone when it comes to prevention and treatment of functional complications. This interdisciplinary approach must focus in prevention of long term complications, such as contractures, abnormal scarring, deformities, muscular atrophy, mobility limitations and other issues which can decrease physical function. Its utilization in a Burn Unit, will help optimize functional results of their patients.(AU)

Individual Shrink Wrapping of Zucchini Fruit Improves Postharvest Chilling Tolerance Associated with a Reduction in Ethylene Production and Oxidative Stress Metabolites.

We have studied the effect of individual shrink wrapping (ISW) on the postharvest performance of refrigerated fruit from two zucchini cultivars that differ in their sensitivity to cold storage: Sinatra (more sensitive) and Natura (more tolerant). The fruit was individually shrink wrapped before storing at 4°C for 0, 7 and 14 days. Quality parameters, ethylene and CO2 productions, ethylene gene expression, and oxidative stress metabolites were assessed in shrink wrapped and non-wrapped fruit after conditioning the fruit for 6 hours at 20°C. ISW decreased significantly the postharvest deterioration of chilled zucchini in both cultivars. Weight loss was reduced to less than 1%, pitting symptoms were completely absent in ISW fruit at 7 days, and were less than 25% those of control fruits at 14 days of cold storage, and firmness loss was significantly reduced in the cultivar Sinatra. These enhancements in quality of ISW fruit were associated with a significant reduction in cold-induced ethylene production, in the respiration rate, and in the level of oxidative stress metabolites such as hydrogen peroxide and malonyldialdehyde (MDA). A detailed expression analysis of ethylene biosynthesis, perception and signaling genes demonstrated a downregulation of CpACS1 and CpACO1 genes in response to ISW, two genes that are upregulated by cold storage. However, the expression patterns of six other ethylene biosynthesis genes (CpACS2 to CpACS7) and five ethylene signal transduction pathway genes (CpCTR1, CpETR1, CpERS1, CpEIN3.1 and CpEN3.2), suggest that they do not play a major role in response to cold storage and ISW packaging. In conclusion, ISW zucchini packaging resulted in improved tolerance to chilling concomitantly with a reduction in oxidative stress, respiration rate and ethylene production, as well as in the expression of ethylene biosynthesis genes, but not of those involved in ethylene perception and sensitivity.

Involvement of ethylene biosynthesis and signalling in fruit set and early fruit development in zucchini squash (Cucurbita pepo L.).

BACKGROUND: We have identified a kind of parthenocarpy in zucchini squash which is associated with an incomplete andromonoecy, i.e. a partial conversion of female into bisexual flowers. Given that andromonoecy in this and other cucurbit species is caused by a reduction of ethylene production in the female flower, the associated parthenocarpic development of the fruit suggested the involvement of ethylene in fruit set and early fruit development. RESULTS: We have compared the production of ethylene as well as the expression of 13 ethylene biosynthesis and signalling genes in pollinated and unpollinated ovaries/fruits of two cultivars, one of which is parthenocarpic (Cavili), while the other is non-parthenocarpic (Tosca). In the latter, unpollinated ovaries show an induction of ethylene biosynthesis and ethylene signal transduction pathway genes three days after anthesis, which is concomitant with the initiation of fruit abortion and senescence. Fruit set and early fruit development in pollinated flowers of both cultivars and unpollinated flowers of Cavili is coupled with low ethylene biosynthesis and signalling, which would also explain the partial andromonoecy in the parthenocarpic genotype. The reduction of ethylene production in the ovary cosegregates with parthenocarpy and partial andromonoecy in the selfing progeny of Cavili. Moreover, the induction of ethylene in anthesis (by ethephon treatments) reduced the percentage of bisexual parthenocarpic flowers in Cavili, while the inhibition of ethylene biosynthesis or response (by AVG and STS treatments) induces not only andromonoecy but also the parthenocarpic development of the fruit in both cultivars. CONCLUSIONS: Results demonstrate that a reduction of ethylene production or signalling in the zucchini flower is able to induce fruit set and early fruit development, and therefore that ethylene is actively involved in fruit set and early fruit development. Auxin and TIBA treatments, inducing fruit set and early fruit development in this species, also inhibit ethylene production and the expression of ethylene biosynthesis and response genes. A model is presented that discusses the crosstalk between ethylene and auxin in the control of fruit set and early fruit development in zucchini squash.

Crop losses due to olive moth mediated by ethylene.

BACKGROUND: Studies for nine years in southern Spain on the olive moth, Prays oleae Bern., have tested the possibility of altering oviposition behaviour on newly formed olive fruits by means of a single ethylene application. RESULTS: A single spraying of ethylene on the olive trees at the beginning of fruiting significantly decreased the olive moth egg populations and consequent the olive fruit fall. At the same time, no negative effect was found in the activity of natural oophagous predators of the olive moth. CONCLUSIONS: The ethylene treatments against P. oleae yielded substantial economical benefits each year (a mean of euro526 ha(-1)), benefits that fluctuated depending on the olive crop and on the annual fruit fall caused by this major pest.