Comportamiento en conservación de cultivares de manzana ‘Reineta del Canadá’

Apple (Malus domestica Borkh) cultivars ‘Reinette du Canada’ (RC) and ‘Reinette Grise du Canada’ (RG) have been declared throughout the European Community as protected designation of origin (PDO) ‘Manzana Reineta del Bierzo’. The aim of this research was to find out the influence of storage technique on quality of PDO apple cultivars ‘RC’ and ‘RG’, and to evaluate the absence of traditional post-harvest treatments in these high quality cultivars in order to reduce pesticide residues in fruit. Apples were kept in standard cold storage or in controlled atmosphere (CA). At harvest time and during storage, fruit from each treatment and storage technique was analysed to determine quality parameters as well as disorder incidence. CA storage has been useful to delay the maturity process of PDO apple cultivars ‘RC’ and ‘RG’ and to reduce the incidence of storage disorders. Apple cultivars had different behaviour so ‘RG’ cultivar showed lower weight loss (5.1%), shrivelling (6.4%) and bitter-pit (11%) than ‘RC’ cultivar (8.3%, 60.8% and 34%, respectively) at the end of storage. The response of both cultivars to the treatment was quite different, so ‘RG’ adapted better than ‘RC’ to the absence of postharvest treatments. Untreated ‘RG’ showed more brightness, total soluble solids (TSS) and TSS:titratable acidity values than treated ‘RG’, factors that could improve consumer acceptance. Effectiveness of postharvest treatment in terms of bitter-pit was lower in ‘RG’ than in ‘RC’. These results indicate that ‘RG’ would adapt better to storage without the use of chemical postharvest treatments.Los cultivares de manzana (Malus domestica Borkh) ‘Reineta del Canadá’ (RC) y ‘Reineta Gris del Canadá’ (RG) han sido declarados en la Unión Europea como Denominación de Origen Protegida (DOP) ‘Manzana Reineta del Bierzo’. El objetivo de este trabajo fue averiguar la influencia de la técnica de conservación en la calidad de los cultivares de la DOP ‘Manzana Reineta del Bierzo’, ‘RC’ y ‘RG’, así como evaluar la ausencia de los tradicionales tratamientos postcosecha en estos cultivares de alta calidad con objeto de reducir los residuos finales en el fruto. Las manzanas fueron almacenadas en frío normal o en atmósfera controlada. En recolección y durante la conservación frigorífica se determinaron los parámetros de calidad y la incidencia de enfermedades. La técnica de atmósfera controlada fue útil para retrasar la maduración de los cultivares DOP ‘Manzana Reineta del Bierzo’ ‘RC’ and ‘RG’ y para reducir la incidencia de alteraciones durante conservación. Los cultivares tuvieron diferente comportamiento, de manera que ‘RG’ mostró menor pérdida de peso (5.1%), arrugamiento (6.4%) y bitter-pit (11%) que ‘RC’ (8.3%, 60.8% y 34%, respectivamente) al final de la conservación. La respuesta de los cultivares ante el tratamiento fue diferente, pues ‘RG’ se adaptó mejor que ‘RC’ a la ausencia de tratamientos. ‘RG’ no tratada mostró mayor brillo, sólidos solubles totales (TSS) y TSS:Acidez titulable que ‘RG’ tratada, lo cual podría aumentar la aceptación por parte del consumidor. La eficacia de los tratamientos postcosecha en el control de bitter-pit fue menor en ‘RG’ que en ‘RC’. Estos resultados indicarían que ‘RG’ se adaptaría mejor a una conservación sin tratamientos químicos postcosecha

Egg development and toxicity of insecticides to eggs, neonate larvae and adults of Xylotrechus arvicola, a pest in Iberian grapevines

Xylotrechus arvicola (Coleoptera: Cerambycidae) is a xylophagous species that is becoming an important pest in vineyards in the Iberian Peninsula. The most sensitive stages are adult and egg, but their neonate larvae can also be attacked during the first 24 h after hatching and before entering the wood. Adults were evaluated for seven days against the insecticides spinosad, Beauveria bassiana, imidacloprid and chlorpyrifos and neonate larvae (< 24 h) and eggs of different ages against the described insecticides, as well as flufenoxuron and pyriproxyfen. All insecticides were applied in a Potter tower at a maximum and minimum commercial dose, and showed significant differences both among insecticides as between the applied doses. Most of the hatching occurs eight days after oviposition by X. arvicola females. Chlorpyrifos had a quick and total control of eggs of different ages, neonate larvae and adults in both dosis applied, but its effectiveness could cause serious effects on other non-target species. Pyriproxifen and flufenoxuron had the best ovicidal control when the age of eggs increases and, B. bassiana also had a good ovicidal control, due its capacity to invade the eggs actively through their shell and proliferate inside them. Biological insecticides such as B. bassiana and spinosad, with a total control on adults and good rates of mortality of neonate larvae and eggs can be a great instrument to biological control of this pest

Biometric traits of Xylotrechus arvicola adults from laboratory and grape fields

Xylotrechus arvicola is a pest in vineyards on the Iberian Peninsula. The action of the larvae, associated to the spread of wood fungi, causes a direct and indirect damage in the crop. This article presents biometric traits of X. arvicola population adults captured in three grape fields with Protected Designation of Origin (PDO) from the Iberian Peninsula and one population of this beetle obtained in the laboratory. The aim of the study was to observe the influence of sex and environment on the size of adults. The adults showed intersexual differences for the length and width of the pronotum, the length and width of the elytra and total length. The wild females were larger than wild males and the males from grape fields were slender than wild females. The environment affected the size of the adults. The laboratory adults reached the greatest body size. The size of the adult reflects the volume of material that had been used as host where the insect had developed. The captured adults in PDO Toro, with Bush Vines Training System (BVTS) were larger than the other PDOs, leading to bigger galleries and exit holes, which could affect the structural resistance of the plant and increase pathogenic fungi infection. However, BVTS facilitates the renovation of attacked branches, which is more difficult and slower in the Bilateral Cordon Training System (BCTS)

Analysis of the mechanical properties of wood attacked by Xylotrechus arvicola (Coleoptera: Cerambycidae) larvae, and its influence on the structural properties of the plant

Xylotrechus arvicola is an invasive insect on Vitis vinifera in the main wine-producing regions of the Iberian Peninsula. X. arvicola larvae bore into the grapevine wood and make galleries, which cause structural damages to the plant. The aim of this study was to investigate how grapevine wood infested by larvae affects the mechanical properties of the plant in comparation with those of uninfested wood. Samples of grapevine wood uninfested and infested by larvae were collected from vineyards. Compression and flexural strengths as well as simulated structures of grapevine wood in field, in relation to harvest weight by variety, were used to quantify the wood mechanical properties. Infested wood endured a lower strength and normal tension, and exhibited a reduction in the structural capacities in the simulation of harvest weight of 'Cabernet-Sauvignon' variety (up to 62.0 %). 'Tempranillo' (despite its high mechanical slenderness values) and 'Cabernet-Sauvignon', were the varieties that showed a higher resistance on trunks and branches, respectively. A lower bending moment was observed on the infested branches of all varieties. Changes in the mechanical properties of infested wood suggest a decrease in mechanical resistance of wood attacked by larvae that could contribute to the rupture of the infested grapevine over time. Grapevine wood attacked by X. arvicola larvae could be more sensitive to mechanical external factors in vineyards such as strong winds, harvest weight and vibration exerted by harvesting machines

Effect of Farnesol in Trichoderma Physiology and in Fungal–Plant Interaction

[EN] Farnesol is an isoprenoid intermediate in the mevalonate (MVA) pathway and is produced by the dephosphorylation of farnesyl diphosphate. Farnesol plays a central role in cell growth and differentiation, controls production of ubiquinone and ergosterol, and participates in the regulation of filamentation and biofilm formation. Despite these important functions, studies of farnesol in filamentous fungi are limited, and information on its effects on antifungal and/or biocontrol activity is scarce. In the present article, we identified the Trichoderma harzianum gene dpp1, encoding a diacylglycerol pyrophosphatase that catalyzes production of farnesol from farnesol diphosphate. We analyzed the function of dpp1 to address the importance of farnesol in Trichoderma physiology and ecology. Overexpression of dpp1 in T. harzianum caused an expected increase in farnesol production as well as a marked change in squalene and ergosterol levels, but overexpression did not affect antifungal activity. In interaction with plants, a dpp1-overexpressing transformant acted as a sensitizing agent in that it up-regulated expression of plant defense salicylate-related genes in the presence of a fungal plant pathogen. In addition, toxicity of farnesol on Trichoderma and plants was examined. Finally, a phylogenetic study of dpp1 was performed to understand its evolutionary history as a primary metabolite gene. This article represents a step forward in the acquisition of knowledge on the role of farnesol in fungal physiology and in fungus-environment interactionsSIThis research was funded by the Spanish I+D+i Grants AGL2012-40041-C02-02, AGL2015-70671-C2-2-R, RTI2018-099600-B-I00 and PID2021-123874OB-I00, financed by the MCIN/ AEI/10.13039/501100011033. GC-H was awarded with a Grant from the Ministry of Education, Culture, and Sport (Spain) (Grant number FPU15/04681). NM-R was awarded with a Grant from the Junta de Castilla y León (Spain) (ORDEN EDU/875/2021, 13 July 2021

Effects of trichothecene production by Trichoderma arundinaceum isolates from bean-field soils on the defense response, growth and development of bean plants (Phaseolus vulgaris)

[EN] The trichothecene toxin-producing fungus Trichoderma arundinaceum has potential as a biological control agent. However, most biocontrol studies have focused only on one strain, IBT 40837. In the current study, three Trichoderma isolates recovered from bean-field soils produced the trichothecene harzianum A (HA) and trichodermol, the latter being an intermediate in the HA biosynthesis. Based on phylogenetic analysis, the three isolates were assigned to the species T. arundinaceum. Their genome sequences had a high degree of similarity to the reference IBT 40837 strain, in terms of total genome size, number of predicted genes, and diversity of putative secondary metabolite biosynthetic gene clusters. HA production by these bean-field isolates conferred significant in vitro antifungal activity against Rhizoctonia solani and Sclerotinia sclerotiorum, which are some of the most important bean pathogens. Furthermore, the bean-field isolates stimulated germination of bean seeds and subsequent growth of above ground parts of the bean plant. Transcriptomic analysis of bean plants inoculated with these T. arundinaceum bean-field soil isolates indicated that HA production significantly affected expression of plant defense-related genes; this effect was particularly significant in the expression of chitinase-encoding genes. Together, these results indicate that Trichoderma species producing non-phytotoxic trichothecenes can induce defenses in plants without negatively affecting germination and developmentSIThis work is a part of the Spanish I+D+i Grants RTI2018-099600-B-I00 and PID2021-123874OB-I00, financed by the MCIN/ AEI/10.13039/501100011033. GC-H was awarded with a Grant from the Ministry of Education, Culture, and Sport (Spain) (Grant number FPU15/04681). NM-R was awarded with a Grant from the Junta de Castilla y León (Spain) (ORDEN EDU/875/2021, July 13th, 2021

Distribution, Function, and Evolution of a Gene Essential for Trichothecene Toxin Biosynthesis in Trichoderma

[EN] Trichothecenes are terpenoid toxins produced by species in 10 fungal genera, including species of Trichoderma. The trichothecene biosynthetic gene (tri) cluster typically includes the tri5 gene, which encodes a terpene synthase that catalyzes formation of trichodiene, the parent compound of all trichothecenes. The two Trichoderma species, Trichoderma arundinaceum and T. brevicompactum, that have been examined are unique in that tri5 is located outside the tri cluster in a genomic region that does not include other known tri genes. In the current study, analysis of 35 species representing a wide range of the phylogenetic diversity of Trichoderma revealed that 22 species had tri5, but only 13 species had both tri5 and the tri cluster. tri5 was not located in the cluster in any species. Using complementation analysis of a T. arundinaceum tri5 deletion mutant, we demonstrated that some tri5 homologs from species that lack a tri cluster are functional, but others are not. Phylogenetic analyses suggest that Trichoderma tri5 was under positive selection following its divergence from homologs in other fungi but before Trichoderma species began diverging from one another. We propose two models to explain these diverse observations. One model proposes that the location of tri5 outside the tri cluster resulted from loss of tri5 from the cluster in an ancestral species followed by reacquisition via horizontal transfer. The other model proposes that in species that have a functional tri5 but lack the tri cluster, trichodiene production provides a competitive advantage.S

Aerosol concentration at two heights (2550 and 650 m a.s.l.) in SE Spain

Ponencia presentada en: XXXV Jornadas Científicas de la AME y el XIX Encuentro Hispano Luso de Meteorología celebrado en León, del 5 al 7 de marzo de 2018.The simultaneous aerosol sampling at two heights in southern Spain may provide valuable information on the vertical structure of the dust transport from North Africa to the Iberian Peninsula. It also allows the characterization of the ambient air at two sites with distinct anthropogenic impact. This work presents the results obtained from the first field campaign of the FRESA project (Impact of dust-laden African air masses and of stratospheric air masses in the Iberian Peninsula. Role of the Atlas Mountains), performed in the period July-November 2017 at El Albergue Universitario in Sierra Nevada (2550 m a.s.l.) and the city of Granada (650 m a.s.l.). The two sites were instrumented with a low-volume sampler with PM10 inlet for daily sampling and mass and chemical composition characterization, a high-volume sampler for total suspended particles (TSP) for weekly sampling and radionuclide activity determination, and with a GRIMM 365 optical particle counter that provides continuously the aerosol size distribution