MartÃnez Fuentes, Amparo
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MartÃnez Fuentes
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Amparo
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- PublicationWarm temperature during floral bud transition turns off EjTFL1 gene expression and promotes flowering in Loquat (Eriobotrya japonica Lindl)(Elsevier, 2023-10) GarcÃa-Lorca, Ana; Reig Valor, Carmina; MartÃnez Fuentes, Amparo; Agustà FonfrÃa, Manuel; Mesejo Conejos, Carlos; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de IngenierÃa Agronómica y del Medio Natural; Universitat Politècnica de València[EN] The Rosaceae family includes several deciduous woody species whose flower development extends over two consecutive growing seasons with a winter dormant period in between. Loquat (Eriobotrya japonica Lindl.) belongs to this family, but it is an evergreen species whose flower bud initiation and flowering occur within the same growing year. Vegetative growth dominates from spring to late summer when terminal buds bloom as panicles. Thus, its floral buds do not undergo winter dormancy until flowering, but a summer heat period of dormancy is required for floral bud differentiation, and that is why we used loquat to study the mechanism by which this summer rest period contributes to floral differentiation of Rosaceae species. As for the deciduous species, the bud transition to the generative stage is initiated by the floral integrator genes. There is evidence that combinations of environmental signals and internal cues (plant hormones) control the expression of TFL1, but the mechanism by which this gene regulates its expression in loquat needs to be clarified for a better understanding of its floral initiation and seasonal growth cycles. Under high temperatures (>25 & DEG;C) after floral bud inductive period, EjTFL1 expression decreases during meristem transition to the reproductive stage, and the promoters of flowering (EjAP1 and EjLFY) increase, indicating that the floral bud differentiation is affected by high temperatures. Monitoring the apical meristem of loquat in June-August of two consecutive years under ambient and thermal controlled conditions showed that under lower temperatures (<25 & DEG;C) during the same period, shoot apex did not stop growing and a higher EjTFL1 expression was recorded, preventing the bud to flower. Likewise, temperature directly affects ABA content in the meristem paralleling EjTFL1 expression, suggesting signaling cascades could converge to refine the expression of EjTFL1 under specific conditions (T<25 & DEG;C) during the floral transition stage.
- PublicationGibberellic acid and flower bud development in loquat (Eriobotrya japonica Lindl.)(Elsevier, 2011) Reig Valor, Carmina; Farina, Vitorio; Volpe, Giorgio; Mesejo Conejos, Carlos; MartÃnez Fuentes, Amparo; Barone, Francesca; Calabrese, Francesco; Agustà FonfrÃa, Manuel; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de IngenierÃa Agronómica y del Medio NaturalThe application of gibberellic acid (GA 3) to the whole loquat tree from mid-May to early June and from early August to the onset of flowering, significantly reduced the number of premature flowering shoots per current shoot and per m 3 of canopy, and so reduced the total number of panicles per m 3 of canopy. The number of vegetative shoots per m 3 of canopy was also significantly reduced by applying GA 3. The response depended on the concentration applied and produced optimal results at 50mgl -1. Differences in the number of flowers per panicle and leaves per shoot were not significantly modified by the treatment. Nevertheless, GA 3 applied directly to the developing apex near to flower differentiation reduced the number of flowers per panicle by 25-35% and without modifying the morphological characteristics of the panicle. Results suggest that less sprouting of lateral buds was largely responsible for the reduction in flowering intensity caused by GA 3. Best treatments reduced thinning costs (60%, approximately) of premature flowering shoots, slightly increased fruit diameter and significantly improved fruit colour and juice quality, thus advancing harvest date. © 2011 Elsevier B.V.
- PublicationToward a more efficient isolation of total RNA from loquat (Eriobotrya japonica Lindl.) tissues(EDP Sciences, 2015-01-20) MartÃnez Fuentes, Amparo; Mesejo Conejos, Carlos; Agustà FonfrÃa, Manuel; Reig Valor, Carmina; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de IngenierÃa Agronómica y del Medio Natural[EN] Loquat (Eriobotrya japonica Lindl.) tissues contain considerable amounts of polyphenolic compounds and polysaccharides which can copurify with RNA. This can render the RNA unsuitable for DNA synthesis and makes the isolation of high quality RNA from loquat tissues particularly difficult. Materials and methods. Total RNA was extracted from leaves, buds and fruit of loquat by adapting the method described by Song et al. in 2011. This involved improvements both to the extraction protocol and RNA purity. Results and discussion. Our modified method resulted in the isolation of high quality RNA with yields 6-20 times higher than that reported for existing methods. We obtained A(260/280) ratios of 2-2.40 A(260/230) ratios of 2-2.31 and RNA integrity numbers (RIN) of 8 to 8.3. The RNA obtained has reached the requested quality for downstream applications such as quantitative real-time polymerase chain reaction (RT-qPCR) experiments.
- PublicationEthylene biosynthesis and perception during ripening of loquat fruit (Eriobotrya japonica Lindl.)(Elsevier, 2017-03) Alós, E.; MartÃnez Fuentes, Amparo; Reig Valor, Carmina; Mesejo Conejos, Carlos; Rodrigo, M.J.; Agustà FonfrÃa, Manuel; ZACARIAS, L.; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de IngenierÃa Agronómica y del Medio Natural; Generalitat Valenciana; Ministerio de EconomÃa y Competitividad; Ministerio de Ciencia e Innovación[EN] In order to gain insights into the controversial ripening behavior of loquat fruits, in the present study we have analyzed the expression of three genes related to ethylene biosynthesis (ACS1, ACO1 and ACO2), two ethylene receptors (ERS1a and ERS1b), one signal transduction component (CTR1) and one transcription factor (EIL1) in peel and pulp of loquat fruit during natural ripening and also in fruits treated with ethylene (10 mu LL-1) and 1-MCP (10 mu LL-1), an ethylene action inhibitor. In fruits attached to or detached from the tree, a slight increase in ethylene production was detected at the yellow stage, but the respiration rate declined progressively during ripening. Accumulation of transcripts of ethylene biosynthetic genes did not correlate with changes in ethylene production, since the maximum accumulation of ACS1 and ACO1 mRNA was detected in fully coloured fruits. Expression of ethylene receptor and signaling genes followed a different pattern in peel and pulp tissues. After fruit detachment and incubation at 20 degrees C for up to 6 days, ACS1 mRNA slightly increased, ACO1 experienced a substantial increment and ACO2 declined. In the peel, these changes were advanced by exogenous ethylene and partially inhibited by 1-MCP. In the pulp, 1-MCP repressed most of the changes in the expression of biosynthetic genes, while ethylene had almost no effects. Expression of ethylene perception and signaling genes was barely affected by ethylene or 1-MCP. Collectively, a differential transcriptional regulation of ethylene biosynthetic genes operates in peel and pulp, and support the notion of non-climacteric ripening in loquat fruits. Ethylene action, however, appears to be required to sustain or maintain the expression of specific genes. (C) 2016 Published by Elsevier GmbH.
- PublicationNaphthaleneacetic acid impairs ovule fertilization and early embryo development in loquat (Eriobotrya japonica Lindl.)(Elsevier, 2014-01-22) Reig Valor, Carmina; Mesejo Conejos, Carlos; MartÃnez Fuentes, Amparo; Agustà FonfrÃa, Manuel; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de IngenierÃa Agronómica y del Medio NaturalBy applying 20 mgl(-1) of alpha-naphthaleneacetic acid (NAA) potassium salt to 'Algerie' loquat tree flowers prior to or at anthesis pollen grain germination was signficantly inhibited and pollen tube growth was halted, both in vivo and in vitro conditions, thus ovule fertilization and fruit set were prevented. These effects of NAA are direct since stigmas were not damaged or dried off by the treatment. Mature but not fertilized ovule and newly fertilized ovule were also sensitive to the gametocidal action of the NAA, whereas new developing seeds did not, both in vivo and in vitro conditions as well. According to our results, NAA acts as a chemical thinner of loquat by preventing ovule fertilization and fruit set and by causing ovule/embryo abortion, depending on the phenological growth stage at treatment. (C) 2013 Elsevier B.V. All rights reserved.
- PublicationSynthetic auxin 3,5,6-TPA increases fruit size of loquat (Eriobotrya japonica Lindl.) by reducing cell turgor pressure(Elsevier, 2016) Reig Valor, Carmina; Mesejo Conejos, Carlos; MartÃnez Fuentes, Amparo; Agustà FonfrÃa, Manuel; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de IngenierÃa Agronómica y del Medio Natural; Ministerio de Ciencia e Innovación[EN] In loquat, the synthetic auxin 3,5,6-trichloro-2 pyridyloxiacetic acid (3,5,6-TPA) applied at 15 mgl(-1) at the onset of the linear fruit growth stage or one month later during the active fruit growth period, advanced fruit ripening and harvest. The treatment significantly accelerated fruit growth and enhanced final fruit diameter by 10% compared to the control. The experiment was conducted on adult trees of 'Algerie' loquat during two consecutive years. 3,5,6-TPA (as a free acid) was sprayed by handgun to the entire tree until the point of run off, using a randomized design with one-tree plots and 8-10 replications. Cell sap water and osmotic potential were measured at the onset of colour change in treated fruit. Fruit growth rate and carbohydrate concentrations were periodically evaluated and at the first harvest date, fruit colour, fruit weight, plant hormone (ABA, GA, IAA, tZ, and JA) content, total soluble solids, titratable acidity, and number of fruits harvested were also recorded. Results confirmed that the effect of 3,5,6-TPA increasing fruit size is due to a reduction of fruit cell turgor pressure that diminished water potential, improving water uptake and increasing carbohydrate contents. (C) 2016 Elsevier B.V. All rights reserved.
- PublicationLoquat Fruit Lacks a Ripening-Associated Autocatalytic Rise in Ethylene Production(Springer-Verlag, 2016) Reig Valor, Carmina; MartÃnez Fuentes, Amparo; Mesejo Conejos, Carlos; Rodrigo, M.J.; Zacarias Garcia, Lorenzo; Agustà FonfrÃa, Manuel; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de IngenierÃa Agronómica y del Medio Natural[EN] Loquat is considered as a non-climacteric fruit; however, there is an evidence of a climacteric-like maturation. Therefore, it seems its ripening behavior has yet to be satisfactory classified. Because autocatalytic regulation of ethylene production during fruit ripening is one of the primary features defining climacteric-like fruit maturation, we examined its ability of autocatalysis during ripening by applying the ethylene-releasing compound ethephon to the on-tree-fruit or ethylene to detached fruit of 'Algerie' loquat and measuring its ethylene and CO2 production. We also analyzed indoleacetic acid (IAA), gibberellin, cytokinin, and abscisic acid (ABA) contents as plant hormones involved in fruit ripening. The fruit response to ethephon (500 mg l(-1)) applied at color change was immediate producing increasing amounts of ethylene during the 4 h following the treatment, but 24 h after treatment onward values were similar to those produced by untreated fruit. Similar results were obtained when applying ethylene to detached fruit (10 mu l l(-1)). Accordingly, applying ethephon (200 mg l(-1)) did not advance harvest; neither the color nor the percentage of fruit harvested at the first picking date differed significantly from the untreated fruit. Flesh firmness, total soluble solid concentration, and acidity of juice were not significantly altered either. IAA concentration reached the maximum value when fruit stopped growing, declining sharply at fruit color change; active gibberellins and cytokinins declined continuously during the fruit growth period, and ABA content sharply increased during ripening, peaking after fruit color break. Results indicate that 'Algerie' loquat lacks a ripening-associated autocatalytic rise in ethylene production, and suggest that a decline in gibberellin, cytokinin, and IAA concentrations might be needed to allow its ripening process to proceed.
- PublicationInvolvement of ethylene in color changes and carotenoid biosynthesis in loquat fruit (Eriobotrya japonica Lindl. cv. Algerie)(Elsevier, 2019-03) Alós, Enriqueta; MartÃnez Fuentes, Amparo; Reig Valor, Carmina; Mesejo Conejos, Carlos; Zacarias, L.; Agustà FonfrÃa, Manuel; Rodrigo-Esteve, Mª Jesús; Dpto. de Producción Vegetal; Instituto Agroforestal Mediterráneo; Escuela Técnica Superior de IngenierÃa Agronómica y del Medio Natural; European Commission; Generalitat Valenciana; Ministerio de Ciencia e Innovación; Ministerio de EconomÃa y Competitividad[EN] In loquat (Eriobotrya japonica Lindl cv. Algerie) fruit, despite the non-climacteric ripening behaviour, evidence suggest that ethylene may participate in the regulation of several ripening- and postharvest-related processes. Color changes and carotenoid profile were analyzed in fruit at three developmental stages (breaker, yellow and colored fruits). At early stages, the fruit peel contained phytoene, phytofluene and other typical chloroplastic carotenoids that decreased during ripening, to accumulate ß-carotene, violaxanthin and ß-cryptoxanthin in mature fruits. In the pulp, carotenoid concentration increased during ripening to become predominant phytoene, followed by ß-carotene and ß-cryptoxanthin. Expression of the carotenoid biosynthetic genes (PSY, PDS, ZDS, CYCB and BCH) was downregulated in the peel during maturation, but increased in the pulp with the exception of BCH. The involvement of ethylene in the regulation of pigmentation was further evaluated by treating fruits at the three ripening stages with ethylene or its action inhibitor 1-MCP. At breaker fruit, ethylene accelerated and 1-MCP delayed fruit coloration, but the effect was progressively lost as fruit matured. Ethylene and 1-MCP produced different changes in carotenoids content and gene expression in peel and pulp. Application of ethylene enhanced ß-carotene content in both tissues whereas ß-cryptoxanthin was only stimulated in the pulp. 1-MCP suppressed these changes in carotenoid composition in the pulp but had little effect in the peel. A differential transcriptional level the pulp was more responsive to downregulated gene expression than the peel. Collectively, results indicate that: 1) ethylene is involved in the regulation of pigmentation and carotenoid biosynthesis in loquat fruits, 2) a differential regulation of carotenoid biosynthesis and response to ethylene appear to operate in the peel and the pulp, and 3) ß-carotene hydroxylase (BCH) is a key step in the regulation of carotenoid content and composition in both tissues of loquat fruit.