ReDivia - Repositorio Digital de l'Instit Valencià d'Investigacions Agràries
Not a member yet
2747 research outputs found
Sort by
Exotic predators can sequester and use novel toxins from exotic non-coevolved prey
Full text linkDefensive chemicals of prey can be sequestered by some coevolved predators, which take advantage of prey toxins for their own defence. The increase in the number of invasive species in the Anthropocene has resulted in new interactions among non-coevolved predator and prey species. While novelty in chemical defence may provide a benefit for invasive prey against non-coevolved predators, resident predators with the right evolutionary pre-adaptations might benefit from sequestering these novel defences. Here, we chose a well-known system of invasive species to test whether non-coevolved predators can sequester and use toxins from exotic prey. Together with the invasive prickly pear plants, cochineal bugs (Dactylopius spp.) are spreading worldwide from their native range in the Americas. These insects produce carminic acid, a defensive anthraquinone that some specialized predators sequester for their own defence. Using this system, we first determined whether coccinellids that prey on cochineal bugs in the Mediterranean region tolerated, sequestered, and released carminic acid in reflex bleeding. Then, we quantified the deterrent effect of carminic acid against antagonistic ants. Our results demonstrate that the Australian coccinellid Cryptolaemus montrouzieri sequestered carminic acid, a substance absent in its coevolved prey, from exotic cochineal bugs. When attacked, the predator released this substance through reflex bleeding at concentrations that were deterrent against antagonistic ants. These findings reveal that non-coevolved predators can sequester and use novel toxins from exotic prey and highlights the surprising outcomes of novel interactions that arise from species invasions
Deciphering the Genetic Basis of Allelopathy in japonica Rice Cultivated in Temperate Regions Using a Genome‑Wide Association Study
Full text linkAllelopathy has been considered as a natural method of weed control. Despite the nature of allelochemical compounds has been studied, little is known about the genetic basis underlying allelopathy. However, it is known that rice exhibits diverse allelopathic potentials across varieties, and breeding for rice plants exhibiting allelopathic potential conferring an advantage against weeds in paddy fields would be highly desirable. Knowledge of the gene factors and the identification of the genomic regions responsible for allelopathy would facilitate breeding programs. Taking advantage of the existing genetic diversity in rice, particularly in temperate japonica rice, we conducted a comprehensive investigation into the genetic determinants that contribute to rice allelopathy. Employing Genome-Wide Association Study, we identified four Quantitative Trait Loci, with the most promising loci situated on chromosome 2 and 5. Subsequent inspection of the genes located within these QTLs revealed genes associated with the biosynthesis of secondary metabolites such as Phenylalanine Ammonia Lyase (PAL), a key enzyme in the synthesis of phenolic compounds, and two genes coding for R2R3-type MYB transcription factors. The identification of these two QTLs associated to allelopathy in rice provides a useful tool for further exploration and targeted breeding strategies
Straw mulching increases soil health in the inter-row of citrus orchards from Mediterranean flat lands
No full textThe inter-rows in woody crop plantations such as citrus orchards are usually not more than alleyways for agricultural operations thus leading to soil health decline spinning around the compaction and soil organic carbon (SOC) loss. In the present scenario of global warming, the soil on the inter-rows of citrus orchards should be recovered for organic carbon trapping with benefits for climate change mitigation and for adaptation through soil health enhancement. Therefore, the aim of this work was to evaluate the effect of a conservation agriculture soil management, specifically, no-till rice straw mulching, on soil health parameters, including SOC, in the inter-rows of two citrus plantations jointly fairly representative of the semi-arid hot-summer Mediterranean climate on flat lands. Temperature, water content, saturated hydraulic conductivity, bulk density (ρb), root abundance, dehydrogenase (DHA) and β-D-glucosidase (GLA) activities, CO2 emission, nitrogen, phosphorus, potassium and organic carbon in the topsoil layer (0 – 20 cm) were studied for almost three years. The rice straw mulching increased the surface albedo by between 0.015 and 0.115, thus reducing mean temperature in the inter-row topsoil by between 0.5 and 1.2 ºC regarding bare soil. The more moderate temperature under the straw mulch fostered a 4-fold higher crop root growth and the subsequent soil macrofauna development, as revealed by the significantly higher DHA and, overall GLA, as well as CO2 emission. Under the straw mulch, the macroporosity rose as revealed by the hydraulic conductivity between twice and 14 times higher. Ultimately the SOC mass fraction increased 10% more under straw than in the bare soil. Therefore, rice straw mulching enhances soil health in citrus orchards of Mediterranean flat lands. However, in remarkably compacted soils, i.e., with ρb over 1.6 g cm-3, the beneficial effects of straw mulching on soil health are still limited after three years of treatment. With such high initial compaction, the search of a kick-off effect by means of adding organic fertilizers and/or amendments alongside a surface tillage operation, might be recommended
Inseminación artificial gallinas
No full textInseminación artificial en gallinas.La inseminación artificial se realiza exteriorizando el oviducto de la gallina (operario 1) y depositando el semen en el interior con ayuda de una pipeta de inseminación (operario 2). Una vez que el operario 2 ha introducido la pipeta en el interior del oviducto, el operario 1 deja de ejercer presión y es en ese momento cuando se debe depositar el semen, teniendo la precaución de no quitar la presión de la pipeta usada para evitar volver a aspirar la dosis de inseminación
Espermatozoides gallos
No full textEspermatozoides móviles de gallosEn este vídeo se muestran espermatozoides móviles de gallos. En esta especie, los espermatozoides son filiformes (forma de hilo)
Plant volatile-triggered defense in citrus against biotic stressors
Full text linkPlants employ sophisticated defense mechanisms, including releasing volatile
organic compounds, to defend against biotic and abiotic stresses. These
compounds play a crucial role in plant defense by attracting natural enemies
and facilitating communication between plants to activate defense mechanisms.
However, there has been no research on how exposure to these compounds
activates defense mechanisms in citrus plants. To elucidate the underlying
mechanisms governing citrus defensive activation, we conducted a molecular
analysis of the rootstock Citrange carrizo [a hybrid of Citrus sinensis × Poncirus
trifoliata] in response to defense activation by the volatile (Z)-3-hexenyl
propanoate [(Z)-3-HP], utilizing a groundbreaking transcriptomic analysis
involving the genomes of both parental species. Our results revealed
significant gene expression changes, notably the overexpression of genes
related to plant immunity, antioxidant activity, defense against herbivores, and
tolerance to abiotic stress. Significantly, P. trifoliata contributed most notably to
the hybrid’s gene expression profile in response to (Z)-3-HP. Additionally, plants
exposed to (Z)-3-HP repelled several citrus pests, attracted natural predators,
and led to diminished performance of two key citrus pests. Our study emphasizes
the complex molecular basis of volatile-triggered defenses in citrus and
highlights the potential of plant volatiles in pest control strategies
Genetic Variation and Evolutionary Analysis of Eggplant Mottled Dwarf Virus Isolates from Spain
Full text linkThe genetic variation and population structure of gene N (nucleocapsid) and part of
gene L (replicase) from 13 eggplant mottle dwarf virus (EMDV) isolates from Spain were evaluated
and compared with sequences of EMDV isolates from other countries retrieved from GenBank.
Phylogenetic inference of part of gene L showed three main clades, one containing an EMDV isolate
from Australia and the other two containing isolates from Iran and Europe, as well as four subclades.
EMDV isolates from Spain were genetically very similar and grouped in a subclade together with
one isolate from Germany and one from the UK. No new recombination events were detected in
addition to one recombination previously reported, suggesting that recombination is rare for EMDV.
The comparison of synonymous and non-synonymous rates showed that negative selection played
an important role, and only two codons were under positive selection. Genetic differentiation (Fst
test), phylogenetic and nucleotide diversity analyses suggest a unique introduction of EMDV to Spain
and low gene flow with other countries. In contrast, Greece and Italy showed diverse populations
with high gene flow between both
Convolutional neural networks to assess bergamot essential oil content in the field from smartphone images
Full text linkThe essential oil (EO) extracted from bergamot peel (Citrus bergamia, Risso et Poiteau) is appreciated in perfumery and gastronomy. Notably, 90 % of the bergamot EO production is concentrated in the Province of Reggio Calabria (Southern Italy) under a protected designation of origin (PDO). The early estimation of EO content in fruits is fundamental to help farmers in their decision at harvesting period. The application of advanced modelling techniques based on artificial intelligence and digital device technology can contribute to this goal. This study proposes a method to estimate the EO content of fruits in the field using classification and regression models based on a deep learning approach in two cultivars: cv. “Fantastico” and cv. “Femminello”. The first step was to capture images of the fruit in the Red, Green, and Blue colours (RGB) using a mid-range smartphone camera and a portable inspection chamber designed and developed for this study. The acquisition of the images was carried out in the field. The fruits were collected and transported to the laboratory, where the EO was extracted using steam hydrodistillation. Custom-built convolutional neural networks (CNN) and three transfer learning models (VGG-16, VGG-19, and Xception architectures) were trained and applied for classification (among different discrete levels of oil content) and regression (to predict the EO content). The classification results showed an accuracy of 0.795 and 0.797 on the test samples of the two cultivars separately, while the best regression model achieved a minimum mean squared error of 0.12 and 0.04 for each cultivar, respectively. The results showed the effectiveness of the approach tested and how modelling each variety independently can lead to better performance for the CNNs tested
Insecticidal Activity of Allium sativum Essential Oil-Based Nanoemulsion against Spodoptera littoralis
Full text linkSpodoptera littoralis, commonly known as the Egyptian or African cotton leafworm, is a significant agricultural threat. It is widely distributed in Africa, Mediterranean Europe, and Middle Eastern countries. This polyphagous pest infests numerous crop plants across 44 families, including cotton, soybeans, alfalfa, sweet potato, pepper, eggplant, tomato, maize, lettuce, strawberry, wheat, and hibiscus. The damage caused by S. littoralis on different plant organs, such as young leaves, shoots, stalks, bolls, buds, and fruits, often determines substantial product losses. Current control strategies predominantly rely on synthetic insecticides, which, despite their efficacy, have notable drawbacks, including insecticide resistance, environmental contamination, consumer concerns, and adverse effects on non-target organisms and beneficial insects. In response to these challenges, in this study, we developed and evaluated a garlic EO-based nanoemulsion with a high EO concentration (15%) and low surfactant content to mitigate the possible negative impact on plants and to enhance efficacy against S. littoralis larvae. Laboratory bioassays demonstrated promising larvicidal activity and reduced larval feeding, although some phytotoxicity symptoms were observed. This study underscores the potential of botanical insecticides as sustainable alternatives to synthetic chemicals, emphasizing the importance of balancing efficacy with environmental and ecological considerations in pest management strategies
Editorial: Deep learning approaches applied to spectral images for plant phenotyping
Full text linkSpectral Imaging, or imaging spectroscopy, is a widespread sensor technology used in
precision agriculture, horticulture and plant phenotyping. From cameras providing just a
few spectral bands on drones, to cameras with a large number of bands, often referred to
as hyperspectral cameras on field vehicles or in greenhouses. For reasons outlined in
(Polder and Gowen, 2020), in this editorial paper, we employ the term “imaging
spectroscopy and spectral imaging”; however, within this Research Topic (RT), it is also
denoted as hyperspectral imaging. Imaging spectroscopy enables plant scientists to quantify
the composition of agricultural products, such as biomass, leaf area, and chlorophyll
content and also detect plant stresses and diseases in an early stage