Celeste Arancibia

Wild potato relatives are valuable sources of drought-adaptive traits, but polyploidization may reshape their stress responses rather than consistently enhance tolerance. Here, we compared a diploid genotype of the wild potato Solanum kurtzianum and its derived autotetraploid line under well-watered (WW) and water-deficit (WD) conditions by integrating phenotypic measurements, MCSeEd-based CG methylation profiling, and mobilome-seq analysis of transposable element (TE)-associated extrachromosomal circular DNA (eccDNA). Water deficit altered biomass allocation, reducing aerial biomass and increasing underground biomass, but did not affect total biomass. The autotetraploid had greater total biomass and leaf relative water content; however, under WD it accumulated more malondialdehyde, whereas the diploid accumulated more proline and showed lower lipid peroxidation. The greatest CG methylation differences between ploidy levels occurred under WW conditions, whereas fewer ploidy-associated differences were detected under WD. Drought-associated methylation differences predominantly reflected lower relative methylation under water deficit and were more numerous in the autotetraploid than in the diploid. Most differentially methylated genes were unique to each ploidy level. Functional interpretation indicated that diploid-specific differentially methylated genes were mainly associated with osmotic and oxidative protection, whereas autotetraploid-specific genes encompassed a broader range of functions, including abscisic acid regulation, carbon metabolism, development, and cellular organization. TE-derived eccDNAs comprised only a small fraction of TE-associated eccDNAs and included both LTR retrotransposons and DNA transposons. Two TE-associated eccDNA were shared across all libraries, both of which were associated with annotated Helitrons, although neither was TE-derived. Overall, water deficit modified phenotypic and molecular responses in both ploidy levels without conferring a general improvement in drought tolerance.

Climate change is advancing ripening and can impair phenolic maturity in grapes, compromising anthocyanins and stilbenes that affect the wine color and stability. We tested whether exogenous abscisic acid (ABA) mitigates warming-induced shifts in the phenylpropanoid pathway in the ’Malbec’ red wine grape variety. A factorial field experiment compared control temperature (−T) and elevated temperature (+T, +2.5 °C), with and without ABA sprays (three applications after veraison). Berry skin gene expression (ten flavonoid and stilbene genes) was monitored across ripening and summarized using time-course and AUC-based clustering. Anthocyanins were quantified in berry skins at harvest and in the corresponding wines, and stilbenes were quantified in wines. Warming reduced MYBA1 early in ripening and decreased anthocyanins and stilbenes overall. Meanwhile, ABA reinforced a late anthocyanin program under −T (MYBA1, UFGT, MYBC2-L3, F3′5′H), consistent with a shift toward the 3′,5′-hydroxylated/malvidin-type branch. Conversely, stilbenes remained suppressed under +T, with limited recovery under +T/+ABA. Time-integrated expression patterns and Spearman correlations consistently linked CHS2, F3′5′H, UFGT, MYBC2-L3, with variation in berry skin anthocyanins across treatments, while STS AUC tracked wine stilbenes. Overall, ABA partially buffered warming effects on ‘Malbec’ color by reinforcing late anthocyanin regulation but did not prevent warming-driven declines in wine stilbenes.

Megaplatypus mutatus, a major poplar pest in South America, tunnels into the xylem, weakening trunks and reducing wood quality. Volatile organic compounds (VOCs) are key mediators of plant–insect interactions and may reflect genotype-specific defence strategies. This study analysed VOC profiles of young and adult Populus deltoides cv. Harvard and P. × canadensis cv. Conti 12 under natural M. mutatus infestation. Gas chromatography–mass spectrometry putatively annotated 31 VOCs, including green leaf volatiles (GLVs), pentyl leaf volatiles (PLVs), terpenes, alcohols, aromatics and phenolics, 12 of which, to our knowledge, have not been previously reported in Populus VOC profiles. Harvard trees showed ~14.5-fold higher total VOC abundance than Conti trees. In Conti, constitutive VOC emissions remained stable regardless of infestation status or age. In contrast, under infestation, Harvard trees emitted10-fold higher constitutive VOCs than non-infested Harvard trees and ~52-fold higher than Conti, a pattern consistent with increased defensive activity. GLVs and PLVs relatively dominated both genotypes, although Harvard showed higher emissions. Terpenes were not detected in young Conti trees under our analytical conditions but were abundant and diverse in infested Harvard trees, which may indicate a stronger terpene-associated response in this clone. Several compounds were detected only under specific genotype–condition combinations in our dataset and therefore represent candidate volatiles for future behavioural and functional studies. These results are consistent with differences in VOC emission patterns between genotypes and age classes, improve our understanding of putative chemical cues in the interaction between Populus and M. mutatus, and provide a basis for future work towards sustainable pest management strategies.

Aquaporins play a key role in plant responses to drought. Our previous work showed limited embolism in grapevine leaves under mild water stress and suggested that the outside-xylem water pathway plays a dominant role in reducing leaf hydraulic conductance ( K _leaf ) during dehydration. We used CRISPR-Cas9 to knockout the PIP2;1 aquaporin encoding gene in Vitis vinifera cv. Chardonnay to study how leaf function during dehydration is affected by this aquaporin isoform. We measured functional responses like stomatal and photosynthetic responses as well as K _leaf to compare wild-type and two independent PIP2;1 knockout lines. Under moderate drought, mutants maintained greater stomatal conductance ( g _s ) and photosynthetic rates as Ψ _w declined. No significant differences were observed in mesophyll conductance ( g _m ) across genotypes, however, mutants exhibited slightly higher values under moderate drought. Interestingly, all lines exhibited similar K _leaf vulnerabilities to drought. Our findings show that PIP2;1 induces earlier stomatal closure during dehydration while not modulating K _leaf responses across genotypes. This rapid response in WT plants would prevent further water loss that would lead to higher xylem tensions that can lead to embolism. These findings show that multiple mechanisms collectively limit leaf gas exchange and water loss during dehydration, enhancing our understanding of plant resilience to changing environments.

Leptochloa crinita is a native forage grass from arid and semi-arid regions of the Americas, typically used for range grazing. Forage biomass productivity

Understanding the impact of rising environmental temperatures on Vitis vinifera is crucial for the wine industry in the context of global warming. This study investigated the combined effects of elevated daytime temperatures (ET) and moderate irrigation restriction (IR) at post-veraison, over four seasons in two widely cultivated cultivars in Argentina: Malbec and Bonarda. An open-top chamber with a passive air heating system was used to increase average daytime temperatures by approximately 2 °C. In general, vegetative growth parameters were not affected by ET or IR throughout the study, indicating no cumulative effects. Bonarda yield was reduced by ET due to fewer berries per bunch, and lighter berries and clusters, but remained unaffected by IR. In contrast, Malbec maintained stable yields under both ET and IR, suggesting greater adaptability. In both cultivars, ET led to increased sugar accumulation and higher alcohol content in wines, but also reduced wine colour intensity, colour index, and co-pigmented anthocyanins, while there were cultivar-specific differences. Despite these common negative effects, Malbec showed favourable traits under ET, including improved anthocyanin stability (higher proportions of acylated forms) and increased hue. The IR treatment restored colour intensity and increased the total polyphenol index in both cultivars, and also recovered colour index in Malbec. Overall, our findings suggest that Malbec exhibits greater phenotypic plasticity and potential for high-quality wine production under moderate post-veraison water stress and elevated temperature, compared to Bonarda. This irrigation strategy may help mitigate some of the adverse effects of elevated temperature by preserving wine colour and stability without significantly compromising vine growth or yield.

The current study introduces an innovative direct and active heating system designed for precise temperature control in vineyards. This system serves as a valuable tool for investigating the influence of climate change on grapevine physiology and, consequently, the characteristics of the resulting wine. The research took place in an experimental vineyard located in Mendoza, Argentina, with V. vinifera cvs. trained to a vertical shoot positioning trellis system over two consecutive growing seasons. The system design utilized electric hot water tanks and polypropylene pipes attached to the foliage catch wires. Over two growing seasons, the system consistently elevated the ambient air temperatures within the canopy by 2.5 ± 0.12 °C compared to the control group. This temperature increase emulated the temperature projections for Mendoza as forecasted by the IPCC by the end of this century. The system displayed heating uniformity, as evidenced by the absence of both vertical and horizontal temperature gradients. Additionally, the significant variation in mean daytime and night-time temperatures between the control and heated treatments highlighted the effectiveness of the system in modifying temperature conditions on a diurnal basis. The heated treatment applied with this system proved to have an effective biological impact on the physiology of grapevines. In both seasons, plants under the heated treatment advanced their bud break and harvest dates. The study showed a significant growth enhancement in the heated treatment, with apical shoots extending significantly longer than those in the control treatment. Additionally, the total soluble solids content increased in the heating treatment, while yield decreased, for both experimental seasons. These results illustrate the robust performance of the system throughout the entire growth period, regardless of fluctuations in atmospheric conditions. This study establishes a new foundation for future research on grapevine responses to climate change. It also opens the door to the implementation of effective adaptation strategies in vineyards, promising a more resilient and adaptable future for grape cultivation.

The high-altitude viticulture of Mendoza is being increasingly recognised among the top wine regions worldwide. High levels of solar ultraviolet-B (UV-B) radiation, alluvial heterogeneous soils and cool night temperatures are major influences on Vitis vinifera L. phenotypic characteristics, especially on Malbec, Argentina’s emblematic grapevine variety. In the present work, the effect of intra-vineyard contrasting soil depth on Malbec was evaluated in a high-altitude vineyard (1450 m a.s.l.), over two growing seasons for physiological traits and over three vintages for yield components and berry skin phenolic compounds. The experiment was carried out in two parcels of shallow (SS) and deep (DS) soils, with different physico-chemical characteristics, and submitted to equal irrigation and crop management. Results showed that root depth was not limited by any soil physical constraints and fine roots (< 1 mm) were patchily distributed in sites with higher contents of silt, clay and organic matter in SS. Higher root quantity in SS was related to lower vegetative and reproductive expressions, shorter ripening period and reduced berry size and fruit yield when compared to DS. When SS plants experienced mild water stress (ΨS, stem water potential, between -6 and -9 bar) increments of anthocyanins, total polyphenols and antioxidant capacity in berry skins were observed. However, when SS plants reached ΨS ≤ -10 bar, physiological harm occurred. The results presented contribute to understanding the effects of soil type on Malbec vines during different seasonal environmental conditions, especially in stressful situations, such as those expected by climate change scenarios.

Preference host is an important factor affecting population dynamics in plant-insect interactions. In this research, the two main phylloxera genotypes found in Argentina (gB and gD) were tested on Vitis vinifera cvs. Cabernet Sauvignon, Malbec, Pedro Giménez, Chardonnay, Cereza, Criolla Grande and rootstocks 1103 Paulsen, 101-14 Mgt, and SO4 using an excised root assay. Statistical analysis showed that, survivorship was affected by the interaction of Cultivar and Time, while hatching was influenced by the interaction of Cultivar and Phylloxera genotype. Cultivar also influenced maximum number of adults, developmental time, as well as gross and net reproductive rates. Phylloxera genotype gB developed faster than gD, however, no other significant differences were found between both genotypes. Principal component analysis showed that Pedro Giménez and Criolla Grande grouped closely with high values of reproduction-related variables, suggesting they are the most preferable hosts, followed by Cabernet Sauvignon; while Cereza, Malbec, and Chardonnay were less suitable. None of the rootstocks allowed the establishment of phylloxera colonies. This study will improve the biological understanding of phylloxera in Argentina and help develop tools for its management.