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SUMMARY: Arabidopsis plants were grown in white light (400–700 nm) or in white light supplemented with far‐red (FR) light peaking at 730 nm. FR‐enriched light induced the typical shade avoidance syndrome characterized by enhanced length of seedling hypocotyl and leaf petiole. FR supplementation also caused a noticeable decrease in the carotenoid and chlorophyll content that was attributable to a block of pigment accumulation during plant development. The carotenoid decrease resulted from a downregulation of their biosynthesis pathway rather than carotenoid degradation. The losses of photosynthetic pigments are part of structural and functional rearrangements of the photosynthetic apparatus. The plastoquinone pool was chronically more oxidized in plants acclimated to white + FR light compared to white light‐grown plants. Growth in FR‐enriched light was associated with a higher photochemical efficiency of PSII compared to growth in white light and with a substantial increase in root and shoot biomass production. Light distribution between the photosystems was modified in favor of PSII by an increase in the PSII/PSI ratio and an inhibition of state transitions. Neither LHCII abundance nor nonphotochemical energy dissipation in the PSII chlorophyll antennae were modified significantly by the addition of FR light. A PSI supercomplex, not previously observed in Arabidopsis, was specifically found in plants grown in FR‐enriched light. This large PSI complex contains a supplementary Lhca1‐4 dimer, leading to a total of 6 LHCI antennae instead of 4 in the canonical PSI. Through those photosystem rearrangements and the synergistic interaction with white light, FR light is photosynthetically active and can boost photosynthesis and plant growth. Significance Statement: Arabidopsis plants were grown in white light supplemented or not with far‐red light. Far‐red‐enriched light induced both structural and functional modifications of the photosystems, with noticeable changes in photosynthetic pigment content, photosystem stoichiometry, PSI supercomplex organization, and state transition capacity. Those modifications were associated with an enhancement of photosynthetic electron‐transport efficiency and plant biomass productivity. Through photosystem rearrangements and synergistic interaction with white light, far‐red light is photosynthetically active and can boost photosynthesis and plant growth. [ABSTRACT FROM AUTHOR]

Downy mildew of grapevine (Vitis vinifera), caused by the oomycete Plasmopara viticola, is an important disease that is present in cultivation areas worldwide, and using resistant varieties provides an environmentally friendly alternative to fungicides. DOWNY MILDEW RESISTANT 6 (DMR6) from Arabidopsis is a negative regulator of plant immunity and its loss of function confers resistance to downy mildew. In grapevine, DMR6 is present in two copies, named VvDMR6-1 and VvDMR6-2. Here, we describe the editing of VvDMR6-1 in embryogenic calli using CRISPR/Cas9 and the regeneration of the edited plants. All edited plants were found to be biallelic and chimeric, and whilst they all showed reduced growth compared with non-transformed control plants, they also had reduced susceptibility to P. viticola. Comparison between mock-inoculated genotypes showed that all edited lines presented higher levels of salicylic acid than controls, and lines subjected to transformation presented higher levels of cis-resveratrol than controls. Our results identify VvDMR6-1 as a promising target for breeding grapevine cultivars with improved resistance to downy mildew. [ABSTRACT FROM AUTHOR]

In a consequence of global warming, grapevine trunk diseases (GTDs) have become a pertinent problem to viticulture, because endophytic fungi can turn necrotrophic upon host stress killing the plant. In Neofusicoccum parvum Bt‐67, plant‐derived ferulic acid makes the fungus release Fusicoccin aglycone triggering plant cell death. Now, we show that the absence of ferulic acid lets the fungus secrete 4‐hydroxyphenylacetic acid (4‐HPA), mimicking the effect of auxins on grapevine defence and facilitating fungal spread. Using Vitis suspension cells, we dissected the mode of action of 4‐HPA during defence triggered by the bacterial cell‐death elicitor, harpin. Early responses (cytoskeletal remodelling and calcium influx) are inhibited, as well as the expression of Stilbene Synthase 27 and phytoalexin accumulation. In contrast to other auxins, 4‐HPA quells transcripts for the auxin conjugating GRETCHEN HAGEN 3. We suggest that 4‐HPA is a key component of the endophytic phase of N. parvum Bt‐67 preventing host cell death. Therefore, our study paves the way to understand how GTDs regulate their latent phase for successful colonisation, before turning necrotrophic and killing the vines. Summary statement: During the asymptomatic phase of grapevine trunk diseases (GTDs), the aggressive Neofusicoccum parvum Bt‐67 secretes 4‐ hydroxyphenylacetic acid which has a similar structure to auxins. This metabolite suppressed plant defence mechanisms and downregulated transcripts of GH3, suggesting a key role in quelling the host response. [ABSTRACT FROM AUTHOR]

ABSTRACT Many plant viruses modify the phenotype of their hosts, which may influence the behaviour of their vectors and facilitate transmission. Among them is the turnip yellows virus (TuYV), which can modify the orientation, feeding, and performance of its main aphid vector, Myzus persicae. However, the virus factors driving these mechanisms have not been elucidated. In this study, we compared the feeding behaviour and fecundity of aphids on TuYV‐infected and transgenic Arabidopsis thaliana expressing individual TuYV proteins (CP, RT and P0) to define the role of these proteins in aphid–plant interactions. Aphids on TuYV‐infected plants had shorter pathway phases and ingested phloem sap for longer times, which is expected to promote the acquisition of the phloem‐limited TuYV. No change in aphid fecundity was observed on TuYV‐infected plants. The transmission‐conducive feeding behaviour changes could be fully reproduced by phloem‐specific expression of the capsid protein (CP) in transgenic plants, whereas expression of P0 had minor and RT had no effects on aphid feeding behaviour. We then carried out a metabolomic analysis to determine plant compounds that could be involved in the modification of the aphid behaviour. A few metabolites were specific for TuYV‐infected or CP‐transgenic A. thaliana, and are good candidates for inducing behavioural changes. [ABSTRACT FROM AUTHOR]

Monoterpenes are important constituents of the aromas of food and beverages, including wine. Among monoterpenes in wines, wine lactone has the most potent odor. It was proposed to form via acid-catalyzed cyclization of ( E)-8-carboxylinalool during wine maturation. It only reaches very low concentrations in wine but its extremely low odor detection threshold makes it an important aroma compound., Using LC-MS/MS, we show here that the ( E)-8-carboxylinalool content in wines correlates with their wine lactone content and estimate the kinetic constant for the very slow formation of wine lactone from ( E)-8-carboxylinalool. We show that ( E)-8-carboxylinalool is accumulated as a glycoside in grape ( Vitis vinifera) berries and that one of the cytochrome P450 enzymes most highly expressed in maturing berries, CYP76F14, efficiently oxidizes linalool to ( E)-8-carboxylinalool., Our analysis of ( E)-8-carboxylinalool in Riesling × Gewurztraminer grapevine progeny established that the CYP76F14 gene co-locates with a quantitative trait locus for ( E)-8-carboxylinalool content in grape berries., Our data support the role of CYP76F14 as the major ( E)-8-carboxylinalool synthase in grape berries and the role of ( E)-8-carboxylinalool as a precursor to wine lactone in wine, providing new insights into wine and grape aroma metabolism, and new methods for food and aroma research and production. [ABSTRACT FROM AUTHOR]

Stilbenes, as important secondary metabolites of grapevine, represent central phytoalexins and therefore constitute an important element of basal immunity. In this study, potential genetic variation in Vitis vinifera ssp. sylvestris, the ancestor of cultivated grapevine, was sought with respect to their output of stilbenes and potential use for resistance breeding. Considerable variation in stilbene inducibility was identified in V. vinifera ssp. sylvestris. Genotypic differences in abundance and profiles of stilbenes that are induced in response to a UV-C pulse are shown. Two clusters of stilbene 'chemovars' emerged: one cluster showed quick and strong accumulation of stilbenes, almost exclusively in the form of non-glycosylated resveratrol and viniferin, while the second cluster accumulated fewer stilbenes and relatively high proportions of piceatannol and the glycosylated piceid. For all 86 genotypes, a time dependence of the stilbene pattern was observed: piceid, resveratrol, and piceatannol accumulated earlier, whereas the viniferins were found later. It was further observed that the genotypic differences in stilbene accumulation were preceded by differential accumulation of the transcripts for chalcone synthase (CHS) and stilbene-related genes: phenylalanine ammonium lyase (PAL), stilbene synthase (StSy), and resveratrol synthase (RS). A screen of the population with respect to susceptibility to downy mildew of grapevine (Plasmopara viticola) revealed considerable variability. The subpopulation of genotypes with high stilbene inducibility was significantly less susceptible as compared with lowstilbene genotypes, and for representative genotypes it could be shown that the inducibility of stilbene synthase by UV correlated with the inducibility by the pathogen. [ABSTRACT FROM AUTHOR]

Asynchronicity causes metabolic chimerism in usual grapevine phenological stages, calling for a revisit of berry development at the individual fruit scale. To reveal the dynamics of metabolite composition in grapevine berries without phenological a priori, a dataset of 9,256 ions was obtained on 125 fruits at different stages by non-targeted ultra-performance liquid chromatography coupled to high-resolution mass spectrometry. This large metabolomic dataset was submitted to an analysis workflow combining classification and dimension reduction tools. This led to the clustering of metabolites into 12 specific kinetic patterns and a metabolome-based definition of the pericarp intrinsic clock outperforming expert timing procedures. Such increased temporal resolution enabled the identification of metabolite clusters that are annunciative of the onset of ripening, noticeably characterized by transient lipidic changes and the start of ABA accumulation. We also highlighted a cluster of stilbenes that accumulate during terminal fruit shriveling, after the arrest of phloem unloading. This non-targeted approach enables a more precise characterization of grapevine berry development through the concept of metabolomic clock. The discovery of new metabolic milestones of berry development paves the way toward a better assessment of the impact of environmental changes on the metabolism of non-climacteric fruit, in different genotypes., (© The Author(s) 2025. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)