Short vs. long-distance avocado supply chains: Life cycle assessment Impact associated to transport and effect of fruit origin and supply conditions chain on primary and secondary metabolites

Avocado consumption and trade are increasing worldwide, with North America and Europe being the main importing regions. Spain is the major European avocado producer (90% of the production), yet it only supplies 10% of the market. Consequently, more than 90% of the avocados consumed in Europe are imported from overseas, mainly from Chile and Peru. In this work, the Life Cycle Assessment (LCA) impact associated with the transport of two avocado supply chains (short (Spanish) and long (Chilean)) and the effect of the fruit origin and distance of both chains on primary and secondary metabolites from harvest to edible ripeness were evaluated using a gas chromatography-mass spectrometry (GC-MS) and liquid chromatography coupled to diode array detection (LC-DAD) based metabolite analysis. The LCA transport impact of the fresh supply chain from production centers in Chile (Quillota) and Spain (Malaga), and then the distribution to several cities in Europe, suggested road export from Spain to European capitals to have the lowest impact (0.14 to 0.22 kg CO2 eq/kg of avocado). When export from Chile was considered, the option of oceanic freight to European ports closer to final destinations was clearly a better option (0.21 to 0.26 kg CO2 eq/kg) than via the Algeciras port in Spain followed by road transport to final destinations in European capitals (0.34 to 0.43 kg CO2 eq/kg), although the situation could be somewhat different if the avocados are transported from the destination ports in northern Europe to long-distance capitals in other European countries. Fruit origin had a significant impact on avocado primary and secondary metabolites. The conditions of the supply chain itself (10 d in cold storage in regular conditions vs. 30 d cold storage + controlled atmosphere conditions) largely influence the fate of some metabolites that certainly affect the pool of metabolites at edible ripeness. The long-assumed hypothesis that the longer the supply chain the more negative impact on nutritional and functional compounds might not hold in this case, as long as transport conditions are adequate in terms of temperature, atmosphere conditions, and time considering distance from origin to destination.This research was funded by Fondecyt Nº 1180303 and REDBIO0001 PCI from ANID (Chile) and for the RTI2018-099139-B-C21 from Ministry of Science and Innovation (Spain)—National Research Agency (MCIN/AEI/10.13039/501100011033) and by “ERDF A way of making Europe”, of the European Union. R. Pedreschi and E. Aguayo are thankful to the grant of Fundación Séneca (Murcia, Spain) through the “Jiménez de la Espada” Program of Visiting Researchers. This research was partially supported by the grant VRIEA-PUCV Nº 039.436/2020

Proteomic and low-polar metabolite profiling reveal unique dynamics in fatty acid metabolism during flower and berry development of table grapes

Grapevine development and ripening are complex processes that involve several biochemical pathways, including fatty acid and lipid metabolism. Fatty acids are essential components of lipids, which play crucial roles in fruit maturation and flavor development. However, the dynamics of fatty acid metabolism in grape flowers and berries are poorly understood. In this study, we present those dynamics and investigate the mechanisms of fatty acid homeostasis on ‘Thompson Seedless’ berries using metabolomic and proteomic analyses. Low-polar metabolite profiling indicated a higher abundance of fatty acids at the pre-flowering and pre-veraison stages. Proteomic analyses revealed that grape flowers and berries display unique profiles of proteins involved in fatty acid biosynthesis, triacylglycerol assembly, fatty acid β-oxidation, and lipid signaling. These findings show, for the first time, that fatty acid metabolism also plays an important role in the development of non-oil-rich tissues, opening new perspectives about lipid function and its relation to berry quality

Modulación del metabolismo primario y secundario de cerezas (Prunus avium l.) sometidas a estrés mecánico mediante tratamiento con melatonina

El pitting superficial es un desorden fisiológico en cerezas el cual puede ser observado como una o más depresiones en la superficie de la fruta. Este daño puede ocurrir durante los procesos de cosecha, recolección y/o empaque, pero se desarrolla en el almacenamiento en frío algunos días o semanas después de la magulladura. La susceptibilidad al pitting varía entre cultivares, la cual se relaciona con una respuesta metabólica al estrés oxidativo, por frío y mecánico. Tratamientos con melatonina durante la postcosecha de cerezas han mostrado un aumento de compuestos fenólicos, antocianinas y mayor capacidad antioxidante. Por lo tanto, el objetivo de este estudio fue evaluar los cambios metabólicos en cerezas sometidas a tratamiento con melatonina e inducción al pitting superficial (daño mecánico). Se aplicó melatonina (400 µM) a cerezas mediante un método de aspersión, en cambio, para el grupo control se aplicó agua destilada. Para ambos tratamientos se dejó secar por 1 h a temperatura ambiente y se almacenó a 1 ºC por 16 h. Toda la fruta fue sometida a daño mecánico (0.098 N) y almacenada a 1 ºC por 20 días. El tratamiento con melatonina atenuó la gravedad del daño por pitting durante el almacenamiento en frío. Con respecto a la expresión de rutas metabólicas, después de un corto tiempo de tratamiento con melatonina y almacenamiento en frío (16 h y 10 d), las cerezas presentaron una regulación positiva en las rutas metabólicas relacionadas con la biosíntesis de metabolitos secundarios (e.g. fenilpropanoides, flavonoides y antocianinas), con la biosíntesis de compuestos estructurales de la membrana plasmática (e.g., esfingolípidos) y con el metabolismo del azufre. La síntesis de compuestos fenólicos fue significativamente más alta en las primeras 16 h de aplicación del tratamiento. En cambio, el aumento del metabolismo del azufre y esfingolípidos fueron significativos a los 10 d de almacenamiento en frío. Es posible que la tolerancia al frío proporcionada por la melatonina en las cerezas esté relacionada con la activación de distintas rutas metabólicas, las cuales podrían estar reduciendo la incidencia del estrés mecánico en las cerezas.Facultad de Ciencias Agrarias y Forestale

Metabolomics Reveals Specific Metabolic Changes in Sweet Cherries (<i>Prunus avium</i> L.) Subjected to Postharvest Treatment with Melatonin after Mechanical Stress

Sweet cherry may develop surface pitting during prolonged cold storage, and susceptibility among varieties is related to metabolites in response to cold and mechanical damage. This study aimed to evaluate the metabolic changes in sweet cherry fruits subjected to melatonin treatment and induced surface pitting. Melatonin (400 µM) was applied to sweet cherries before pitting induction and then stored at 1 °C for 20 d. Melatonin treatment attenuated the severity of pitting damage during cold storage, with an average severity value of 3.1 for cherries with melatonin and 2.6 without melatonin. In addition, melatonin application appeared to modulate metabolic responses due to the regulation of metabolic pathways related to abiotic stress. Upregulation of different secondary metabolites was observed after 16 h of melatonin treatment and cold storage. Moreover, some metabolites of the sphingolipid and sulfur metabolism were upregulated after 10 d. This research is the first to show that melatonin may influence the response of sweet cherries to cold and mechanical damage

Controlled Atmosphere Storage Alleviates Hass Avocado Black Spot Disorder

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 &deg;C for 40 d; T2: controlled atmosphere storage (CA) of 4 kPa O2 and 6 kPa CO2 at 5 &deg;C for 40 d; T3: 10 d RA + 30 d CA and T4: 5 &micro;M 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

A First Omics Data Integration Approach in Hass Avocados to Evaluate Rootstock–Scion Interactions: From Aerial and Root Plant Growth to Fruit Development

Grafting, the careful selection of rootstocks and scions, has played a crucial role maintaining Chilean avocado fruit quality standards in a scenario in which climate change and drought-related issues have considerably decreased avocado fruit production in the last fifteen years. The historical use of seedling rootstocks in Chile has experienced a recent shift towards clonal rootstocks, driven by the potential to produce more consistent and predictable crops. This research aims to compare Hass avocado plants grafted on Mexicola seedling and Dusa® clonal rootstocks in a soilless and protected system using (i) a differential expression analysis of root and leaf samples and (ii) a fruit transcriptomic and metabolomic integration analysis to improve our understanding of rootstock–scion interaction and its impact on avocado tree performance and fruit quality. The results demonstrated that no significant transcriptomic and metabolomic differences were identified at fruit level in the ready-to-eat (RTE) stage for Hass avocado fruit from both rootstocks. However, Hass avocados grafted on the clonal rootstock showed greater aerial growth and slightly increased fruit size than the seedling rootstock due to the enrichment of cell wall-remodeling genes as revealed in leaves and fruit at harvest stage

Controlled Atmosphere Storage Alleviates Hass Avocado Black Spot Disorder

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

Differential Hydraulic Properties and Primary Metabolism in Fine Root of Avocado Trees Rootstocks

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

Differential Hydraulic Properties and Primary Metabolism in Fine Root of Avocado Trees Rootstocks

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. &ldquo;Hass&rdquo; grafted on &ldquo;Dusa&rdquo; (D, clonally propagated) and &ldquo;Mexicola&rdquo; (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 &ldquo;Mexicola&rdquo; 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