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El cultivo del caqui
No full textActualmente, las enfermedades causadas por hongos son uno de los principales problemas fitosanitarios del caqui en nuestro país. El aumento exponencial de la superficie de cultivo y la escasa diversidad varietal han propiciado
la aparición de nuevas patologías en este frutal. Por otra parte, con el aumento de la producción y el acceso a nuevos mercados de exportación
más lejanos, se ha incrementado notablemente la duración del período de conservación frigorífica. Esta práctica ha tenido como consecuencia un aumento de la incidencia de patologías fúngicas de poscosecha
Acta Horticulturae
No full textA proteomic study was used to know more about the Citrus redox state and stress response related to fruit load. To this end, we researched for differences in the accumulation of proteins related to these processes between on-crop and off-crop 'Moncada' mandarin leaves. Samples were collected in November, were immediately stored frozen at -80 degrees C, and proteins were extracted in less than two weeks. From 2D DIGE gel of these extracts, 12 related spots were isolated: only 1 showed increased accumulation in the off-crop samples compared to on-crop samples, while the other 11 showed increased accumulation in the on-crop samples against off-crop samples. These spots were identified by MALDI-MS or LC-MS-MS. The only protein with increased expression in the off-crop samples was putative monocopper oxidase precursor, while the up-expressed proteins in on-crop leaves were catalase, monodehydroascorbate reductase, Fe-superoxide dismutase, glutathione peroxidase, and three proteins related to stress response. Thus according to these results, generally, in the off-crop samples, proteins with oxidoreductase activity are down-regulated, while in the on-crop samples the proteins related to stress response and to oxidoreductase activity are up-regulated. Therefore, the redox state is different for off-crop and for on-crop Citrus leaves
Comparative study of the protein profiles of Sunki mandarin and Rangpur lime plants in response to water deficit
Get PDFBackground: Rootstocks play a major role in the tolerance of citrus plants to water deficit by controlling and
adjusting the water supply to meet the transpiration demand of the shoots. Alterations in protein abundance in
citrus roots are crucial for plant adaptation to water deficit. We performed two-dimensional electrophoresis (2-DE)
separation followed by LC/MS/MS to assess the proteome responses of the roots of two citrus rootstocks, Rangpur
lime (Citrus limonia Osbeck) and ‘Sunki Maravilha’ (Citrus sunki) mandarin, which show contrasting tolerances to
water deficits at the physiological and molecular levels.
Results: Changes in the abundance of 36 and 38 proteins in Rangpur lime and ‘Sunki Maravilha’ mandarin,
respectively, were observed via LC/MS/MS in response to water deficit. Multivariate principal component
analysis (PCA) of the data revealed major changes in the protein profile of ‘Sunki Maravilha’ in response to
water deficit. Additionally, proteomics and systems biology analyses allowed for the general elucidation of the
major mechanisms associated with the differential responses to water deficit of both varieties. The defense
mechanisms of Rangpur lime included changes in the metabolism of carbohydrates and amino acids as well as
in the activation of reactive oxygen species (ROS) detoxification and in the levels of proteins involved in water
stress defense. In contrast, the adaptation of ‘Sunki Maravilha’ to stress was aided by the activation of DNA repair
and processing proteins.
Conclusions: Our study reveals that the levels of a number of proteins involved in various cellular pathways are
affected during water deficit in the roots of citrus plants. The results show that acclimatization to water deficit
involves specific responses in Rangpur lime and ‘Sunki Maravilha’ mandarin. This study provides insights into the
effects of drought on the abundance of proteins in the roots of two varieties of citrus rootstocks. In addition,
this work allows for a better understanding of the molecular basis of the response to water deficit in citrus.
Further analysis is needed to elucidate the behaviors of the key target proteins involved in this response
Acta Horticulturae
No full textIn citrus, the use of rootstocks promotes productivity, improves fruit quality and may confer resistance or tolerance to biotic and abiotic stress. ‘Rangpur’ lime (Citrus limonia, Osbeck) is one of the most tolerant rootstock to drought and is largely used by the Brazilian citrus industry. Previous studies have shown that, when grafted with a variety citrus doubled diploid (4x) ‘Rangpur’ lime rootstock is more tolerant to drought stress than the respective diploid (2x). In the present study, we characterized the water deficit tolerance in 2x and 4x ‘Rangpur’ lime seedlings. Water deficit was applied respectively for 21 days, followed by recovery irrigation. Physiological and biochemical parameters were measured periodically during the experiment and samples were collected for biochemical analysis. Doubled diploid seedlings were showed to be more water deficit tolerant than 2x. Water deficit caused a greater reduction in stomatal conductance in 2x compared to 4x. The 21st day of stress, leaf water potential in 2x was lower. Analyses of the activity of enzymes involved in detoxification process suggest that the better tolerance of 4x genotypes may be related to better scavenging of reactive oxygen species
Efficacy of Pseudomonas chlororaphis subsp. aureofaciens SH2 and Pseudomonas fluorescens RH43 isolates against root-knot nematodes (Meloidogyne spp.) in kiwifruit
Get PDFThe Root-knot nematodes, Meloidogyne spp., are parasites of many crops and orchards, including kiwifruit trees. The Islamic Republic of Iran is among the leading kiwifruit producers in the world and M. in- cognita has been found as the dominant species responsible for severe loss of this crop. In order to evaluate the effectiveness of antagonistic bacteria on larval mortality, number of galls per plant and egg masses of nematode reduction, fifty local bacterial strains were isolated from root surrounding soils of kiwifruit plants in the northern production areas in Iran. Bacterial antagonists were characterized by morphological, physiological, biochemical and molecular methods. Two representative strains, showing the best nematicidal activity, were identifed as Pseudomonas chlororaphis subsp. aureofaciens (isolate Sh2) and Pseudomonas fluorescens (isolate Rh43). They increased the percentage of larval mortality to 56.38% and 54.28% respectively in assays in vitro and showed excellent performance also in vivo with consistent reduction of number of galls (67.31% and 55.63%, respectively) and egg mass (86.46% and 84.29%, respectively) in plants. This study indicates that Pseudomonas chlororaphis subsp. aureofaciens isolate Sh2 and Pseudomonas fluorescens isolate Rh43 are good potential biocontrol agents for containing root-knot nematodes in kiwifruit trees
Effect of maturity stage at processing and antioxidant treatments on the physico-chemical, sensory and nutritional quality of fresh-cut 'Rojo Brillante' persimmon
No full textThe aim of this work was to study the effect of the maturity stage (MS), storage at 15 °C before processing and antioxidant application on the quality of fresh-cut ‘Rojo Brillante’ persimmons. The MS at harvest had an effect on both fruit firmness and the efficacy of the antioxidants to control enzymatic browning. Nutritional quality was affected by MS and storage time before processing, but not by antioxidant application. For commercial purposes, the persimmons harvested at the beginning of the season could be processed as a fresh-cut commodity, even after 3 days of storage at 15 °C if treated with 0.01 kg L−1 ascorbic acid (AA) or 0.01 kg L−1 citric acid (CA). However, processing fruits from late season immediately after harvest and being treated with AA are recommended. The limit of marketability of fresh-cut ‘Rojo Brillante’ persimmons was reached after 6 and 8 days with AA and CA, respectively
Effect of luteinizing hormone on rabbit ovarian superstimulation and embryo developmental potential
Get PDFAssisted reproduction technologies require ovarian stimulation to increase the number of oocytes and embryos. Currently, superstimulation is achieved by gonadotropin treatment, but the embryo yield and quality are highly variable. Commonly, commercial preparations derived from pituitary and urinary origin are used to superovulate. Hence, ovarian superstimulation protocols have usually included both FSH and LH. The appearance of recombinant gonadotropins manufactured by genetic engineering techniques has ensured high quality and batch-to-batch consistency. Moreover, this enables us to assess the importance of LH in the ovarian stimulation. The main aim of this study was to evaluate the effect of recombinant human LH supplementation (10%) on embryonic development produced by rabbit does superovulated with low or high concentration (18.75 or 37.50 IU) of recombinant human FSH (rhFSH). Females treated with rhFSH increased the ovulation rate, and it was significantly higher when the high FSH dose was supplemented with LH. The superstimulation treatment used did not significantly affect in vitro development rate until the expanded blastocyst stage. The results of this study seem to suggest that, in terms of superovulatory response, when rabbit does are treated with 37.5-IU rhFSH, the use of LH supplementation allows an increase in the number of follicles recruited and the quality of embryos, in terms of ability to develop in vitro until blastocyst, and the expression profile of OCT4, NANOG, and SOX2 genes is not affected
Acta Horticulturae
No full textCitrus vein enation (VE), a graft-transmissible disease naturally spread by several aphid species in a persistent mode, has been reported in many citrus growing areas. It causes vein enations on leaves and woody galls on trunk and branches of sensitive citrus species such as Mexican lime, rough lemon and Citrus volkameriana. The disease is currently diagnosed by biological indexing on sensitive indicator plants, an expensive and time-consuming method. In order to identify its causal agent and develop specific and reliable molecular detection methods, we analyzed small RNAs (sRNAs) from VE-infected Etrog citron plants by deep sequencing using the Illumina Solexa platform. Assembly of VE-associated sRNAs yielded several contigs that showed sequence homology with Pea enation mosaic virus 1 (PEMV-1), the type species of genus Enamovirus, family Luteoviridae. The gaps between adjacent contigs were filled by RT-PCR amplification, cloning and sequencing in order to obtain the complete genome sequence of a new virus, Citrus vein enation virus (CVEV). The CVEV genomic RNA has 5,983 nt organized in five open reading frames, resembling that of PEMV-1. Phylogenetic comparison of amino acid signatures in RNA-dependent RNA polymerases of the family Luteoviridae clearly grouped CVEV with PEMV-1. Therefore, we propose that CVEV should be included in the genus Enamovirus. A rapid and specific detection procedure was developed based on RT-PCR with CVEV-specific primers
How a slow-ovipositing parasitoid can succeed as a biological control agent of the invasive mealybug Phenacoccus peruvianus: implications for future classical and conservation biological control programs
Get PDFPhenacoccus peruvianus Granara de Willink (Hemiptera: Pseudococcidae) is an invasive mealybug that has become a pest of ornamental plants in Europe and has recently been detected in California, USA. In this work, we studied the tritrophic interaction among this mealybug, its main parasitoid Acerophagus n. sp. near coccois (Hymenoptera: Encyrtidae) and tending ants to disclose the success of this parasitoid controlling P. peruvianus. Acerophagus n. sp. near coccois accepted mealybugs for parasitism regardless of their size but did not host-feed. We recorded three active defenses of P. peruvianus. Host handling time was not influenced by these host defenses but was a time-consuming process that required more than 30 min. Tending ants, Lasius grandis (Hymenoptera: Encyrtidae), reduced the time spent by parasitoids in a patch and disrupted oviposition attempts. The low numbers of ants tending mealybug colonies in Spain and France could explain why this parasitoid, with a long handling time, is an efficient biological control agent for P. peruvianus
Colchicine-induced polyploidy in loquat (Eriobotrya japonica (Thunb.) Lindl.)
No full textThe induction of polyploids in loquat (Eriobotrya japonica (Thunb.) Lindl.) is of great interest for producing larger and seedless fruits according to market demands. Under this premise, this work was aimed to obtain tetraploid plants of loquat using the antimitotic agent colchicine. Experiments consisted in applying colchicine on shoot apex from in vitro-grown plants, in vitro-grown whole plants and ungerminated seeds. Treatments on the shoot apex or submerging whole plants produced no stable polyploids. Conversely, subjecting ungerminated seeds to colchicine produced two triploids in the 0.5 % (w/v) solution after 24 h and one tetraploid after 48 h. The triploids obtained among treated seeds make us believe that these plants were present in the hybrids original seedlot. Polyploidy levels were firstly detected by flow cytometry and later confirmed by chromosome counting and morphological characteristics. The relative fluorescence was 1.5-fold higher in triploids and twofold higher in tetraploids as compared to diploids. As expected, the chromosome number was 2n = 34 in diploids, 2n = 51 in triploids and 2n = 68 in the tetraploid. Moreover, differences in morphological characteristics between diploid and polyploid plants were significant. The tetraploid plant was more compact than triploids or diploids. Particularly, stomata of polyploids were larger with lower density than diploids. Results indicate that induction of polyploidy in loquat species is a reliable tool for breeding new loquat varieties