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The Dual Benefit of Plant Essential Oils against Tuta absoluta
Get PDFPlant essential oils (PEOs) are being studied as a potential alternative to synthetic pesticides in agriculture. PEOs have the potential to control pests both directly, by being toxic or repellent to pests, and indirectly, by activating plant’s defense mechanisms. In this study, the effectiveness of five PEOs (Achillea millefolium, Allium sativum, Rosmarinus officinallis, Tagetes minuta, and Thymus zygis) on controlling Tuta absoluta and their impact on the predator Nesidiocoris tenuis was examined. The study revelead that PEOs from A. millefolium and A. sativum-sprayed plants significantly reduced the number of T. absoluta-infested leaflets and did not affect the establishment and reproduction of N. tenuis. Additionally, the spraying of A. millefolium and A. sativum increased the expression of defense genes in the plants, triggering the release of herbivory-induced plant volatiles (HIPVs), such as C6 green leaf volatiles, monoterpenes, and aldehydes, which can be messengers in tritrophic interactions. The results suggest that PEOs from A. millefolium and A. sativum can provide a dual benefit for controlling arthropod pests, as they can directly exhibit toxicity against these pests while also activating plant defense mechanisms. Overall, this study provides new insights into using PEOs as a sustainable solution for controlling pests and diseases in agriculture, by reducing synthetic pesticides and promoting the use of natural predators
Postharvest Application of Potato Starch Edible Coatings with Sodium Benzoate to Reduce Sour Rot and Preserve Mandarin Fruit Quality
Get PDFStarch is a biodegradable polymeric carbohydrate that can easily form films and coatings and can readily be obtained from some food industry by-products and wastes, which may contribute to the circular bioeconomy. In this work, we studied the potential of two edible coating emulsions based on pregelatinized potato starch (PPS) and glyceryl monostearate (GMS) alone (F6 and F10) or formulated with the food additive sodium benzoate (SB, 2%) (F6/SB and F10/SB) to control sour rot, an important citrus postharvest disease caused by the fungus Geotrichum citri-aurantii, and maintain postharvest quality of cold-stored ‘Orri’ mandarins. The PPS-GMS coating application was compared to dipping in water (uncoated controls) and dipping in a 2% SB (w/v) aqueous solution. The results showed that the coating F10/SB was the most promising treatment to control sour rot on mandarins, with reductions in disease incidence with respect to the uncoated control samples of 94, 69, and 55% after 2, 4, and 6 weeks of storage at 5°C, respectively. Coatings formulated without SB were ineffective. Regarding fruit quality, the coating F10 was the most effective to reduce weight loss, maintain firmness, and provide gloss on mandarins stored at 5°C for up to 6 weeks followed by a shelf-life period of 1 week at 20°C. The addition of SB to the PPS-GMS coatings adversely affected these coating properties, but the coating F10/SB still reduced weight loss compared to uncoated controls without negatively affecting the fruit physicochemical (juice titratable acidity, soluble solids content, and volatiles content) and sensory quality (overall flavor, off-flavors, external aspect). Overall, the coating F10/SB showed the greatest potential for commercial use as an efficient and environmentally friendly alternative to conventional fungicides and waxes for sour rot control and quality preservation of cold-stored mandarins
Assessment of citrus reproductive biology for seedless mandarin production and its interaction with temperature
Get PDFSince the origin of citrus, ancestral natural hybridizations, thousands of years of cultivation and admixture phenomenon have resulted in the complexity of the reproductive biology of today’s cultivated citrus, which often involves female and male sterility, self-incompatibility, parthenocarpy and apomixis in different degrees. The global objective of this PhD was to increase our knowledge on different reproductive aspects that are crucial for citrus breeding and propagation and their interaction with environmental conditions.
Temperature in the progamic phase is critical for the success of plant sexual reproduction. Pollen grain germination, stigmatic receptivity and pollen tube growth are the main components of this phase. The analysis of temperature effect on the progamic phase of citrus was our first objective. We developed an innovative method based on the microscopic observation of transversal slices from pollinated pistils collected daily, allowing a more comprehensive analysis of the pollen tube growth kinetics and dynamics along the pistil. Using three compatible crosses within the Citrus genus, we evaluated, with this method, the effect of four temperature regimes in every process during the progamic phase. Warm temperatures reduced the time needed by pollen tubes to reach the ovules and also accelerate pistil degeneration while cold temperatures produced the opposite effects. However, pollen tubes were able to reach the ovules in all crosses studied. Interestingly, we observed for the first time in citrus both pollen germination and pollen tube growth at 10ºC. Mandarins account for 24% of total citrus production and seedlessness is a crucial quality criterion for the mandarin fresh fruit market. Parthenocarpic ability (PA) is the key for seedless fruit production when it is coupled with self-incompatibility (SI) or sterility. The second objective of this PhD dissertation was to evaluate PA and SI for mandarin varieties with relevant characteristics as parents for seedless mandarin breeding. For this purpose, we developed an efficient protocol based on emasculation, hand self-pollination and hand cross-pollination. Pollen performance was analysed by histological observations, together with fruit set and seed production. Six different behaviors were observed among the nine varieties analysed. 'Clemenules' clementine and 'Moncada' mandarins were strictly self-incompatible with facultative and vegetative parthenocarpy; 'Imperial' mandarin and 'Ellendale' tangor displayed no strict self-incompatibility associated with facultative and vegetative parthenocarpy; 'Fortune' mandarin was self-incompatible with facultative and stimulative parthenocarpy; 'Campeona' and 'Salteñita' mandarins were self-compatible with vegetative parthenocarpy; 'Serafines' satsuma was associated with male sterility together with facultative and vegetative parthenocarpy; 'Monreal' clementine was self-compatible and non-parthenocarpic. Beyond the critical importance of SI for seedless fruit production, SI is an obstacle for breeding programs based on hybridization as it reduces crossing possibilities. The third objective of this PhD dissertation was to compare the efficiency of the SI reaction breakdown by three factors previously identified in other plant species: temperature stress, bud pollination and polyploidization. The SI phenotype was characterized for two self-incompatible varieties ‘Fortune’ and ‘Clemenules’ by a histological study of pollen tube growth and ovule fertilization. A molecular analysis with SSRs and SNPs markers allowed us to demonstrate that all the obtained plants were zygotic from selfing. The three methods were successful in recovering selfed plants, and bud pollination was the most efficient approach. Chromosome doubling was also efficient, but involved developing tetraploid plants. Cold temperature stress allowed us to obtain a few diploid selfed plants. However, this method proved much more complex to apply than bud pollination in specific breeding programs. Marker-assisted selection (MAS) allows the selection of target genotypes at the seedling stage, making it a powerful tool, especially in tree species with long juvenile period, such as citrus. The 4th objective of this PhD dissertation focuses on the development of SNPs markers associated with polyembryony and male sterility. Polyembryony (a form of apomixis) is a desired trait for rootstock production, while monoembryony is researched for parents of sexual breeding projects. Male sterility is useful coupled with parthenocarpy for seedless fruit production and satsuma-derived nucleo-cytoplasmic male sterility (CMS) is the most prevalent in mandarins. In Chapter 4, a segregating offspring derived from ‘Kiyomi’ (a monoembryonic and CMS variety) × ‘Murcott’ (a polyembryonic and male fertile variety) was genotyped by genotyping-by-sequencing (GBS). It was also phenotyped for polyembryony and male sterility by the evaluation of the number of pollen grains per anther (NPGA) and apparent pollen fertility (APF). Through genetic association studies, we identified a genomic region in linkage group 1 associated with polyembryony and a genomic region on linkage group 8 associated with NPGA. SNP markers closely linked with implied genes were developed for the two genomic regions. Overall, this PhD dissertation provides new insights into citrus reproductive biology and the influence of temperature on it. The knowledge generated will allow to implement breeding programs more efficiently, particularly those aimed at obtaining seedless varieties. This knowledge can eventually be used to respond to some of the most pressing challenges posed by the current global warming scenario
Genotyping by Sequencing for SNP-Based Linkage Analysis and the Development of KASPar Markers for Male Sterility and Polyembryony in Citrus
Get PDFPolyembryony and male sterility (MS) are essential characters for citrus breeding. MS, coupled with parthenocarpy, allows for addressing the diversification of diploid seedless mandarin varieties, and nucleocytoplasmic MS is the most prevalent system. Polyembryony limits the use of seed parents in scion breeding programs, and the recovery of monoembryonic hybrids to be used as female parents is a crucial pre-breeding component. The objectives of this work were the identification of SNPs closely linked with the genes implied in these traits for marker-assisted selection. Genotyping by sequencing was used to genotype 61 diploid hybrids from an F1 progeny recovered from crossing ‘Kiyomi’ and ‘Murcott’ tangors. A total of 6444 segregating markers were identified and used to establish the two parental genetic maps. They consisted of 1374 and 697 markers encompassing 1416.287 and 1339.735 cM for ‘Kiyomi’ and ‘Murcott’, respectively. Phenotyping for MS and polyembryony was performed. The genotype–trait association study identified a genomic region on LG8 which was significantly associated with MS, and a genomic region on LG1 which was significantly associated with polyembryony. Annotation of the identified region for MS revealed 19 candidate genes. One SNP KASPar marker was developed and fully validated for each trait
Complete circularized genome resources of seven strains of Xylella fastidiosa subsp. fastidiosa using hybrid assembly reveals unknown plasmids
No full textXylella fastidiosa (Xf) is a vascular plant pathogenic bacterium native to the Americas that is causing significant epidemics and economic losses in olive and almonds in Europe, where it is a quarantine pathogen. Since its first detection in 2013 in Italy, mandatory surveys across Europe revealed the presence of the bacterium also in France, Spain, and Portugal. Combining ONT and Illumina sequencing data, we assembled high-quality complete genomes of seven Xf subsp. fastidiosa strains isolated from different plants in Spain, the USA, and Mexico. Comparative genomic analyses discovered differences in plasmid content among strains, including plasmids that had been overlooked previously when using Illumina sequencing platform alone. Interestingly, in strain CFBP8073, intercepted in France from plants imported from Mexico, three plasmids were identified, including two (plasmid pXF-P1.CFBP8073 and pXF-P2.CFBP8073) not previously described in X. fastidiosa, and one (pXF5823.CFBP8073) almost identical to a plasmid described in a Xf strain from citrus. Plasmids found in the Spanish strains here were similar to those described previously in other strains from the same subspecies and ST1 isolated in the Balearic Islands and the USA. The genome resources from this work will assist in further studies on the role of plasmids in the epidemiology, ecology, and evolution of this plant pathogen
Risk-based regionalization approach for area-wide management of HLB vectors in the Mediterranean Basin
Get PDFHuanglongbing (HLB) is one of the most devastating citrus diseases worldwide. It is associated with the non-culture bacteria Candidatus Liberibacter spp., which can be transmitted by grafting and/or the psyllid vectors Diaphorina citri (ACP) and Trioza erytreae (AfCP). Although HLB has not been reported in the Mediterranean Basin to date, both vectors are present, and thus represent a serious threat to the citrus industry in this region. Resistant citrus cultivars or effective therapeutic treatments are not currently available for HLB. Nevertheless, area-wide pest management via coordinated management efforts over large areas has been implemented in Brazil, China and the USA for HLB control. This study proposes an open access flexible methodology to address area-wide management of both HLB vectors in the Mediterranean Basin. Based on a risk-based approach which considers climatic information and other variables that may influence vector introduction and spread, such as conventional, organic, abandoned and residential citrus areas as well as transportation corridors, an area-wide management division in pest management areas (PMAs) is proposed. The size and location of these PMAs were estimated by means of a hierarchical clustering algorithm with spatial constraints whose performance was assessed under different configuration scenarios. This proposal may assist policymakers and the citrus industry of the citrus-growing areas of the Mediterranean Basin in risk management planning in the case of the spread of HLB vectors or a possible introduction of the disease. Additionally, it may be a valuable resource to inform opinion dynamic models, enabling the identification of pivotal factors for the success of control measures
Principales cambios fisicoquímicos durante la maduración de la naranja sanguina ‘Tarocco Ippolito’
Get PDFLas naranjas sanguinas se caracterizan por tener un elevado contenido en antocianinas, lo que las hace especialmente saludables y de interés para un consumidor cada vez más consciente del papel que la alimentación juega en su salud. Recientemente ha cobrado interés en España la variedad ‘Tarocco Ippolito’ debido a su coloración y sabor, y se han establecido las primeras plantaciones. En este estudio se evaluaron los principales cambios fisicoquímicos durante el crecimiento y maduración de los frutos de esta variedad. Para ello, desde finales de septiembre hasta la recolección comercial a mediados de enero, se realizó un seguimiento en campo del color y diámetro. A partir del viraje de color se recolectó fruta semanalmente para evaluar los siguientes parámetros: color externo, color de zumo, sólidos solubles totales (SST), acidez titulable, índice de madurez (IM), rendimiento en zumo, contenido de antocianinas totales e individuales. Nuestros resultados muestran que el viraje de color de tonos verdes a amarillos tuvo lugar a principios de noviembre, cuando la fruta presentaba un IM=5.6. La síntesis de antocianinas comenzó a finales de noviembre cuando la fruta presentaba un IM=7.1. La acidez descendió gradualmente desde valores de 1.6 g ac/100 mL en viraje de color hasta valores de 1 g ac/100 mL en la recolección, mientras que los SST aumentaron desde 8.8 hasta 10.7°Brix en recolección. Mediante cromatografía de líquidos (UPLC-MS) se identificaron 4 antocianinas individuales: cyanidin-3-O-glucoside, cyanidin-3-(6”malonyl)-O-glucoside, delphinidin-3-O-glucoside, cyanidin-3-(6”dioxalyl)-O-glucoside, siendo las dos primeras las mayoritarias durante toda la maduración. En el momento de la recolección la fruta presentó un peso medio de 219 g, un IM=11, un rendimiento en zumo del 43% y un color externo y color de zumo (a*/b* de CieLab) de 0.60 y 0.64 respectivamente. En este momento el contenido de antocianinas totales fue de 30.6 mg/L
Estudio de las distancias recorridas por cerdos ibéricos en premontanera. Resultados preliminares
Get PDFDifferential gene expression patterns and physiological responses improve adaptation to high salinity concentration in pepper accessions
No full textHigh salinity decreases the productivity of crops worldwide. Pepper is particularly
sensitive to high salt concentrations. Herein, we subjected three tolerant pepper
accessions (C12, B14 and A25) to high sodium chloride concentration (70 mM NaCl).
The aerial and root biomass, leaf and root osmotic potential (Ψπ), Na+, Cl , K+ and
proline concentrations and the relative expression of the putative genes CaSOS1,
CaHKT1, three CaNHXs and CaP5CS were measured. Different salinity tolerance
strategies depending on the pepper accession were identified. In C12, tolerance was
attributed to the accumulation of Na+ in vacuoles and endosomes by the activation
of vacuolar CaNHXs genes and the reduction in Ψπ; additionally, the activation of
CaHKT1 and CaSOS1 in leaves and roots moved and accumulated Na+ ions in the
xylem and xylem parenchyma cells (XPC) as well as expulsed it out of the root cells.
A25 accession, on the contrary, was specialized in compartmentalizing Na+ ions in
root and leaf vacuoles and root XPC by the up-regulation of CaNHXs and CaHKT1,
respectively, avoiding a toxic accumulation in leaves. Finally, B14 accession moved
and accumulated Na+ in xylem and XPC, reducing its concentration in roots by the
activation of CaSOS1 and CaHKT1. This study shade light on different tolerance
mechanisms of pepper plants to overcome salt stres
Estimación genética de 2060 variables espectrales mediante análisis multivariados de datos crudos
Get PDFLa información utilizada en los programas de mejora genética que incluyen la calidad química de la
leche parte de los análisis de las muestras del Control Lechero Oficial llevados a cabo por los laboratorios
oficiales. Estas analíticas se basan en estimas obtenidas indirectamente a partir de los datos espectrales
del infrarrojo medio por transformada de Fourier (FT-MIR) de las muestras de leche. Pero ¿qué
ocurriría si hiciéramos selección directa por alguna/s de las variables del espectro? (Belay et al., 2018).
El objetivo sería proponer un enfoque alternativo, con la predicción directa (PD) evaluando genéticamente
a los individuos a partir de los espectros lecheros caprinos habiendo estimado los parámetros
genéticos (PG) utilizando o no técnicas de reducción de variables