The classification of grapevine cultivars into isohydric and anisohydric categories depends on their ability to close stomata under conditions of low soil water availability or high atmospheric demand. This study aimed to compare the responses of Grenache, classified as isohydric, and Cabernet Sauvignon, classified as anisohydric, both grafted onto Richter 110 rootstock, and subjected to severe drought stress. Three cycles of drought stress were applied, followed by watering, while a well-watered treatment served as the control. Stomatal conductance and stem water potential were measured at predawn and midday during the drought cycles, and primary metabolites were analyzed in leaves and roots using gas chromatography. We found that Grenache had significantly higher stomatal conductance than Cabernet Sauvignon under both well-watered and water-stressed conditions. There were no significant differences in stem water potential between the two varieties, but the control treatment maintained a higher stem water potential at predawn and midday for both varieties. Primary metabolite analysis showed that both varieties accumulated sugars and polyols in their leaves and roots under drought stress, while organic acids were more abundant in leaves than in roots. Overall, the results suggest that the hydric behavior of grapevines depends on the intensity and duration of drought stress. In this study, both varieties exhibited near-isohydric behavior by regulating stomatal closure under drought stress. The metabolites identified in this study may serve as potential biomarkers of water drought stress in Grenache and Cabernet Sauvignon grapevines under the conditions of this experiment.

As it was previously reported, black spot development in the skin of Hass avocado has been related to a decreased antioxidant defense system. The aim of this study was to investigate the effect of different postharvest storage conditions on controlling black spot development targeting their effect on the antioxidant system (non-enzymatic and enzymatic) of the skin. Four postharvest treatments (T1: regular air storage (RA) at 5 °C for 40 d; T2: controlled atmosphere storage (CA) of 4 kPa O₂ and 6 kPa CO₂ at 5 °C for 40 d; T3: 10 d RA + 30 d CA and T4: 5 µM methyl jasmonate (MeJA) for 30 s + 10 RA + 30 d CA) were tested on controlling black spot incidence in fruit from six orchards from different agroclimatic zones and harvests. Then, on two selected orchards and harvests, the evolution of total phenolics (TPC), antioxidant capacity (AC) and antioxidant enzymes (catalase (CAT), polyphenol oxidase (PPO), superoxide dismutase (SOD), peroxidase (POD), phenylalanine ammonia lyase (PAL)) was monitored. Results revealed that incidence of black spot disorder was not associated to an agroclimatic zone and harvest stage. Immediate application of CA (T2) controlled black spot development during prolonged storage (40 d) and under these conditions TPC content remained higher compared to the other treatments. No clear role of CAT, PPO, SOD, POD and PAL on controlling black spot was observed. The results obtained are of value for the Hass avocado supply chain since a clear performance of CA was evidenced that will result in reduction of postharvest losses associated to this problem.

Antarctic soil represents an important reservoir of filamentous fungi (FF) species with the ability to produce novel bioactive lipids. However, the lipid extraction method is still a bottleneck. The objective of the present work was to isolate and identify cultivable FF from Antarctic soils, to assess the most effective methods for fatty acid (FA) extraction, and to characterise the obtained lipids. A total of 18 fungal strains belonging to the Botrytis, Cladosporium, Cylindrobasidium, Mortierella, Penicillium, Pseudogymnoascus, and Talaromyces genera and the Melanommataceae family were isolated and identified. The Folch, Bligh and Dyer, and Lewis extraction methods were assessed, and methyl esters of FA (FAMEs) were obtained. The Lewis method was the best in recovering FAMEs from fungal biomass. A total of 17 FAs were identified, and their chemical compositions varied depending on fungal species and strain. Oleic, linoleic, stearic, and palmitic acids were predominant for all fungal strains in the three assessed methods. Among the analysed strains, Cylindrobasidium eucalypti, Penicillium miczynskii, P. virgatum, and Pseudogymnoascus pannorum produced high amounts of FA. This suggests that the soils of Antarctica Bay, as well as harbouring known oleaginous fungi, are also an important source of oleaginous filamentous fungi that remain poorly analysed.

Avocados (Persea americana Mill.) are one of the crops with the highest water footprints in Chile and the production is at risk due to severe and frequent droughts. The current production is mostly based on sexually (seed) propagated rootstocks, while clonally propagated rootstocks are on the rise. In a recent study, we found differences in aerial, root growth and water use efficiency between trees grown on these two different rootstocks under controlled continuous fertigation and environmental conditions. In this study, we further describe possible mechanisms which drive the differences. Avocado cv. “Hass” grafted on “Dusa” (D, clonally propagated) and “Mexicola” (M, sexually propagated) rootstocks and different root segments (3, 5 and 8 cm from root tip) were investigated using a combination of hydraulic measurements and polar metabolite (GC-MS) techniques. The results show significant differences in root hydraulic properties, indicating that “Mexicola” fine roots have higher water uptake capacity. The polar metabolites analysis revealed 13 compounds significantly different between rootstocks while nine were found significantly different among root segments. Principal component analysis (PCA) revealed differences between rootstocks and root segments. The data presented here highlight the importance of considering key physiological knowledge in avocado rootstocks breeding programs to be better prepared for future challenging environmental conditions.