•Substantial reprogramming of hormonal metabolism occurs during grape ripening.•Grape cultivars differ in the metabolism of ABA, IAA and jasmonates during ripening.•Substantial reprogramming of ...hormonal metabolism occurs during grape defense.•Salicylic acid and IAA may be involved in defense against Botrytis cinerea.•High basal levels of SA, jasmonates and IAA and signaling are associated with tolerance.
Hormones play an important role in fruit ripening and in response to biotic stress. Nevertheless, analyses of hormonal profiling during plant development and defense are scarce. In this work, changes in hormonal metabolism in grapevine (Vitis vinifera) were compared between a susceptible (Trincadeira) and a tolerant (Syrah) variety during grape ripening and upon infection with Botrytis cinerea. Infection of grapes with the necrotrophic pathogen Botrytis cinerea leads to significant economic losses worldwide.
Peppercorn-sized fruits were infected in the field and mock-treated and infected berries were collected at green, veraison and harvest stages for hormone analysis and targeted qPCR analysis of genes involved in hormonal metabolism and signaling. Results indicate a substantial reprogramming of hormonal metabolism during grape ripening and in response to fungal attack. Syrah and Trincadeira presented differences in the metabolism of abscisic acid (ABA), indole-3-acetic acid (IAA) and jasmonates during grape ripening that may be connected to fruit quality. On the other hand, high basal levels of salicylic acid (SA), jasmonates and IAA at an early stage of ripening, together with activated SA, jasmonates and IAA signaling, likely enable a fast defense response leading to grape resistance/ tolerance towards B. cinerea.
The balance among the different phytohormones seems to depend on the ripening stage and on the intra-specific genetic background and may be fundamental in providing resistance or susceptibility. In addition, this study indicated the involvement of SA and IAA in defense against necrotrophic pathogens and gains insights into possible strategies for conventional breeding and/or gene editing aiming at improving grape quality and grape resistance against Botrytis cinerea.
Abstract Morphoanatomy and histochemistry of Baccharis palustris: insights into a highly endangered endemic species from Southeastern America. The phenotypic plasticity of the Baccharis genus makes ...species identification difficult, even at the flowering stage. In this context, morphoanatomical studies are a powerful tool for botanical authentication, mainly emphasizing the recognition of diagnostic characteristics that may be useful for distinguishing similar species. Given the limited knowledge available about the endemic species B. palustris, this work aimed to characterize the morphoanatomy and histochemistry of its vegetative aerial parts to identify characters with diagnostic value and to elucidate the sites of synthesis and accumulation of metabolites of medicinal importance. B. palustris leaf showed pinnate, camptodrome-brochidodrome venation patterns. Blade with dorsiventral mesophyll, aerenchymatous spongy parenchyma, collateral vascular bundles, and different types of stomata and trichomes, including glandular trichomes with a multi-layered base evidenced and described for the first time in the genus. The petiole was winged, with three collateral vascular bundles. The stem showed a penta-lobulated contour with unusual growth, starch, and crystals in the pith. The presence of secretory ducts and glandular trichomes, which synthesized lipids, terpenes/polyacetylenes, and phenolic compounds, was observed. The morphological/histochemical characteristics described in this work contribute to the knowledge of the species, highlighting the importance of its preservation as a valuable resource.
Resumen Morfoanatomía e histoquímica de Baccharis palustris: ampliando el conocimiento de una especie endémica altamente amenazada del sureste de América. La plasticidad fenotípica del género Baccharis dificulta la identificación de las especies, incluso en la etapa de floración. En este contexto, la descripción morfoanatómica es una herramienta poderosa para la autenticación botánica, haciendo hincapié en las características de valor diagnóstico que pueden ser útiles para distinguir especies similares. Dado el escaso conocimiento disponible sobre la especie endémica B. palustristis, el objetivo de este trabajo fue caracterizar la morfoanatomía y la histoquímica de las partes aéreas vegetativas de B. palustris y establecer los sitios de síntesis y acumulación de metabolitos de importancia medicinal. La hoja de B. palustris mostró venación pinnada, camptódroma, broquidódromo. Lámina con mesofilo dorsiventral con parénquima esponjoso aerenquimático, haces vasculares colaterales y distintos tipos de estomas y tricomas, entre los que se destacan tricomas glandulares de base pluriceriada nunca antes descriptos para el género. El pecíolo se presentó alado, con tres haces vasculares colaterales. El tallo mostró contorno pentalobulado con crecimiento poco usual, almidón y cristales en la médula. Se observó la presencia de conductos secretores y tricomas glandulares, los cuales pueden sintetizar lípidos, terpenos/poliacetilenos y compuestos fenólicos. Las características morfológicas/histoquímicas descritas en este trabajo contribuyen al conocimiento de la especie, destacando la importancia de su preservación como un recurso valioso.
The mild climate and, in recent decades, the increased demand for timber have favoured the establishment of extensive plantations of fast-growing species such as Pinus radiata in Galicia (a ...fire-prone region in northwestern Spain). This species is characterised by very poor self-pruning; unmanaged pine stands have a worrying vertical continuity of fuels after crown closure because the dead lower branches accumulate large amounts of fine dead biomass including twigs and suspended needles. Despite the important contribution of these dead ladder fuels to the overall canopy biomass and to crown-fire hazards, equations for estimating these fuels have not yet been developed. In this study, two systems of equations for estimating dead ladder fuel according to size class and the vertical distribution in the first 6 m of the crown were fitted: a tree-level system based on individual tree and stand variables and a stand-level system based only on stand variables. The goodness-of-fit statistics for both model systems indicated that the estimates were robust and accurate. At the tree level, fuel biomass models explained between 35% and 59% of the observed variability, whereas cumulative fuel biomass models explained between 62% and 81% of the observed variability. On the other hand, at the stand level, fuel-load models explained between 88% and 98% of the observed variability, whereas cumulative fuel-load models explained more than 98% of the total observed variability. These systems will therefore allow managers to adequately quantify the dead ladder fuels in pure Pinus radiata stands and to identify the treatments required to reduce crown-fire hazard.
Grapevine is regarded as a highly profitable culture, being well spread worldwide and mostly directed to the wine-producing industry. Practices to maintain the vineyard in healthy conditions are ...tenuous and are exacerbated due to abiotic and biotic stresses, where fungal grapevine trunk diseases (GTDs) play a major role. The abolishment of chemical treatments and the intensification of several management practices led to an uprise in GTD outbreaks. Symptomatology of GTDs is very similar among diseases, leading to underdevelopment of the vines and death in extreme scenarios. Disease progression is widely affected by biotic and abiotic factors, and the prevalence of the pathogens varies with country and region. In this review, the state-of-the-art regarding identification and detection of GTDs is vastly analyzed. Methods and protocols used for the identification of GTDs, which are currently rather limited, are highlighted. The main conclusion is the utter need for the development of new technologies to easily and precisely detect the presence of the pathogens related to GTDs, allowing to readily take phytosanitary measures and/or proceed to plant removal in order to establish better vineyard management practices. Moreover, new practices and methods of detection, identification, and quantification of infectious material would allow imposing greater control on nurseries and plant exportation, limiting the movement of infected vines and thus avoiding the propagation of fungal inoculum throughout wine regions.
The biotrophic fungus
Erysiphe necator
causes powdery mildew (PM) in grapevine. Phytohormones are major modulators of defensive responses in plants but the analysis of the hormonome associated with ...grapevine tolerance and susceptibility against this pathogen has not been elucidated. In this study, changes in hormonal profiling were compared between a tolerant (
Vitis rupestris
×
riparia
cv. 101-14 Millardet et de Grasset) and a susceptible (
Vitis vinifera
cv. Aragonêz) species upon
E. necator
infection. Control and PM-infected leaves were collected at 0, 6, 24, 96 h post-infection (hpi), and analysed through LC-MS/MS. The results showed a distinct constitutive hormonome between tolerant and susceptible species. Constitutive high levels of salicylic acid (SA) and indole-3- acetic acid together with additional fast induction of SA within the first 6 hpi as well as constitutive low levels of jasmonates and abscisic acid may enable a faster and more efficient response towards the PM. The balance among the different phytohormones seems to be species-specific and fundamental in providing tolerance or susceptibility. These insights may be used to develop strategies for conventional breeding and/or editing of genes involved in hormonal metabolism aiming at providing a durable resistance in grapevine against
E. necator
.
Black foot is an important disease of grapevines, which has in recent years been recorded with increased incidence and severity throughout the world, affecting grapevines both in nurseries and young ...vineyards. In the past the disease has been associated with infections by Ilyonectria macrodidyma, Ilyonectria liriodendri, Campylocarpon fasciculare, and Campylocarpon pseudofasciculare. Based on published data, a high level of genetic diversity was detected among isolates of I. macrodidyma. To resolve this issue, we employed a multigene analysis strategy (based on the β-tubulin, histone H3, translation elongation factor 1-α, and the internal transcribed spacers on both sides of the 5.8S nuclear ribosomal RNA gene) along with morphological characterisation to study a collection of 81 I. macrodidyma-like isolates from grapevine and other hosts. Morphological characters (particularly conidial size) and molecular data (highest resolution achieved with histone H3 nucleotide sequence) enabled the distinction of six monophyletic species within the I. macrodidyma complex, four of which (Ilyonectria alcacerensis, Ilyonectria estremocensis, Ilyonectria novozelandica, and Ilyonectria torresensis) are described here. This work forms part of an effort by the International Council on Grapevine Trunk Diseases to resolve the species associated with black foot disease, which we believe will clarify their taxonomy, and therefore help researchers to devise control strategies to reduce the devastating impact of this disease.
► Ilyonectria macrodidyma (among other fungi) causes black foot disease of grapevines. ► High genetic diversity of this species was investigated using a multigene analysis. ► Monophyletic species were best distinguished based on histone H3 and conidial size. ► Novel species: Ilyonectria alcacerensis, Ilyonectria estremocensis, Ilyonectria novozelandica, and Ilyonectria torresensis.
Grapevine trunk diseases constitute one of the major problems for viticulture worldwide, with Botryosphaeria dieback considered as one of the most important of these diseases. In this work, we aimed ...to (i) evaluate the effect of the combination of two products, Esquive® (a Trichoderma-based product) and LC2017 (a low-copper-based product), in the control of Lasiodiplodia theobromae, by evaluating the internal lesion length caused by inoculation of this pathogen on greenhouse kept grapevines of cvs Cabernet Sauvignon and Touriga Nacional and, (ii) investigating their elicitor effect on plant defense responses, through the analysis of the expression of a set of genes. The pathogen was always re-isolated from the infected tissues and was able to cause wood discoloration. Touriga Nacional exhibited longer lesions than Cabernet Sauvignon, and the application of both products did not appear to reduce lesion length when compared to LC2017 applied alone. The elicitor effect of LC2017 on plant defense was confirmed by gene expression analysis, and no significant differences were found between plants treated with LC2017 and with both products. Moreover, a specific response related to the cultivar was verified, but this apparently unique interaction between product, cultivar and pathogen remains to be further investigated.
The aroma of grapes is cultivar dependent and is influenced by
, vineyard practices, and abiotic and biotic stresses. Trincadeira is a non-aromatic variety associated with low phenolic content and ...high sugar and organic acid levels. This cultivar, widely used in Portuguese wines, presents high susceptibility to
. This work aimed to characterise the volatile profile of Trincadeira grapes and how it changes under infection with
. Thirty-six volatile organic compounds were identified, from different functional groups, namely alcohols, ester acetates, fatty acid esters, fatty acids, aldehydes, and products of the lipoxygenase pathway. Both free and glycosidic volatile organic compounds were analysed by Gas Chromatography and Gas Chromatography coupled to Mass Spectrometry for component quantification and identification, respectively. A multivariance analysis showed a clear discrimination between healthy and infected grapes with 2-
-hexenal and isoamyl-acetate among the compounds identified as negative and positive markers of infection, respectively. Ester acetates such as 2-phenylethyl acetate, isoamyl acetate, and 2-methylbutyl acetate were present in higher contents in infected samples, whereas the contents of several fatty acid esters, such as ethyl decanoate and ethyl dodecanoate, decreased. These data were integrated with quantitative PCR data regarding genes involved in volatile metabolism and showed up-regulation of a gene coding for Hydroperoxide Lyase 2 in infected grapes. Altogether, these changes in volatile metabolism indicate an impact on the grape quality and may be related to defence against
. The presence/absence of specific compounds might be used as infection biomarkers in the assessment of Trincadeira grapes' quality.
Little is known of the response of Portuguese Dão wine appellation's most common grapevine cultivars to the causal agents of esca and Petri diseases, despite the high incidence of both diseases in ...the region and the consequent economic losses. Phaeomoniella chlamydospora has been considered one of the major causal agents of these diseases in that region. The present study evaluated the responses of four of the most propagated Dão's grapevine cultivars – Alfrocheiro, Aragonez, Jaen and Touriga Nacional – to infection by three different Portuguese isolates of P. chlamydospora. Field trials were conducted in 2012, 2013 and 2015. The cultivar Alfrocheiro was the most susceptible to P. chlamydospora while cv. Jaen was the least. Variation in parameters such as lesion length and pathogen recovery from infected spurs (within trial years) suggest relation of pathogenicity with weather data, particularly temperature. Differences in aggressiveness among isolates were also detected, with one, a non-native, being the most aggressive. These results provide valuable information for local winegrowers, identifying, for the first time, susceptibility differences among local cultivars to P. chlamydospora, and suggesting adjustments to recommended pruning strategies, specifically to leave long spurs and avoid late winter pruning, thus reducing grapevine trunk colonization by P. chlamydospora.
Botryosphaeria dieback caused by several Botryosphaeriaceae species is one of the most important grapevine trunk diseases affecting vineyards worldwide. These fungi cause wedge-shaped perennial ...cankers and black streaking of the wood and have also been associated with intervein leaf chlorosis, dried or mummified berries, and eventually, the death of the plant. Early season symptoms may sometimes be disregarded by growers, being mistaken with symptoms from other diseases such as downy mildew or botrytis rot. Currently, few studies are available to determine what species may be causing these early season symptoms in grapevines. During the 2018 season, during the flowering period, grapevine samples showing necrosis on green shoots, dried inflorescences, and flowers, were collected in vineyards throughout the central regions of Portugal. Isolations were performed from symptomatic organs, and twenty-three isolates of Botryosphaeriaceae were selected. An analysis of the ITS and part of the translation elongation factor 1-α sequences was performed, revealing that the two main species apparently responsible for these symptoms were Diplodia seriata and Neofusicoccum parvum. In pathogenicity tests conducted on 1-year-old plants grown under controlled conditions in a greenhouse and on field-grown clusters, symptoms were reproduced, confirming the pathogenic behavior of the selection of isolates.
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