At harvest, leafy vegetables undergo profound metabolic changes, causing oxidative stress and accelerating senescence, compromising their nutritional, nutraceutical, and organoleptic quality. These physiological modifications involve the degradation of key metabolites, affecting both primary and secondary metabolic pathways. Storage conditions play a crucial role in modulating these postharvest alterations, influencing metabolic responses related to oxidative stress, nutrient storage, and overall tissue integrity. Understanding these changes is essential for optimizing postharvest processing strategies and extending shelf life while maintaining the product quality. This study investigates the postharvest metabolic responses of Brassica rapa L. subsp. sylvestris (Friariello Napoletano), ecotype Sessantino, stored at 4 °C and 10 °C for 2 or 20 days. The results show that fresh samples (control) had higher levels (by over 50%) of sugars, proteins, chlorophylls, reduced ascorbate, and relative water content (RWC) compared to stored samples. Storage caused a decrease in sucrose and starch (by 75%), while the presence of several amino acids, including asparagine and glutamine, increased by more than 100% in stored samples. The increase in amides is due to amino acid catabolism, which releases carbon skeletons (acetate and oxalacetate), but also ammonia, which must be re-organicated to avoid further metabolic disturbances. Postharvest senescence was also evident after 20 days at 10 °C, showing a reduction in chlorophylls (by 80%) and ascorbate (by 85%), both of which are essential for preserving photosynthetic efficiency and antioxidant capacity. Interestingly, the tocopherol content increased by over 200%, probably due to the phytol released during chlorophyll degradation. This suggests that tocopherols act as protective molecules against oxidative stress, mitigating cell damage induced by storage conditions. Overall, prolonged cold storage, particularly at 10 °C, induces substantial metabolic changes in Brassica rapa L., reflecting stress adaptation mechanisms and marked changes in primary and secondary metabolism. Understanding these biochemical changes provides valuable indications for improving postharvest handling strategies of leafy vegetables, with the aim of prolonging shelf life while preserving nutritional and functional quality.

In a world increasingly threatened by climate change, the agricultural sector faces several challenges in keeping up with the rising demand for food while minimizing its environmental impacts. With growing awareness of the harmful effects of traditional pesticides and fertilizers, the development of innovative and eco-friendly strategies to protect plant health has become pivotal for sustainable agriculture. In this scenario, ozone (O₃), a powerful oxidizing agent, presents a promising eco-friendly alternative due to its rapid degradation and the fact that it does not release harmful residues into the environment. However, despite its potential, the molecular mechanisms underlying the role of O₃ in plant defenses are not fully understood.

This study aimed to investigate the bioactivity of O₃ on the growth, development, and defense responses of plants. Specifically, O₃ was applied as ozonated water to the soil of plants grown in pots in field experiments. The model plant Nicotiana tabacum and agronomically important crops such as tomato, lettuce, and bean were included in this study. Furthermore, O₃ was directly applied to the nutrient solution of hydroponically grown lettuce. Several physiological parameters were assessed, including plant weight, chlorophyll content, and stomatal conductance, to evaluate the effects of O₃ on plant growth. Moreover, differences in the expression of specific defense-related genes, including those involved in the auxin and salicylic acid (SA) pathways, were evaluated in O₃-treated plants and compared to untreated control plants. The analysis of these physiological parameters revealed that the effects of O₃ were species-specific, with varying responses among the plant species tested. Additionally, gene expression analysis revealed that the O₃ treatment led to significant changes in hormonal and defense signaling pathways. Notably, O₃ induced plant defenses, primarily through the activation of pathogenesis-related (PR) proteins and the SA pathway. Overall, these findings provide valuable insights into the potential of O₃ as an elicitor of plant defense mechanisms, which could enhance plants' resistance to both biotic and abiotic stresses.

We established the first transcriptome of Dendromecon rigida, known as Tree Poppy. It can be distinguished from other Papaveraceae by its lanceolate leaves and woody stems, which are uncommon for the family. During the same sampling event, we procured metagenomic data from the rootzone soil bacteria. Alkaloid production and gene expression in this plant have been little studied, although the plant’s resilience following a disturbance is most certainly related to its secondary metabolites as well as its fire ecology. The interest in this plant comes from its resistance to pathogens, as well as its potential for synergy in the production of secondary metabolites with rootzone microbes, based on our previous work. The plant is known to have few pest and disease problems due to the high amount of antifungal, antioxidant, anti-herbivory, and insecticidal compounds like berberines within it.

The data we procured consisted of 16S metabarcoding, WGS metagenomics, and plant whole transcriptome data from Tree Poppy leaf, flower, and fruit. The metagenomics analysis employed QIIME2, Nephele, and STAMP. The plant transcriptome was assembled de novo in Trinity, expression was quantified with salmon, and completeness was assessed using BUSCO. Transcripts were annotated with the best SPROT blastx hits, and of those with a length> 1000 and TPM>10, a subset of secondary metabolite and resistance genes were selected for further analysis.

The assembly had a total of 369,483 transcripts with an average length of 856 and a high degree of completeness >95%. From the transcripts, several candidate genes for alkaloid production were identified including methyltetrahydroprotoberberine, (RS)-norcoclaurine, S-stylopine, and 3-O-actylpapaveroxine. Protoberberines have antifungal properties and contribute to allelopathy. Norcoclaurine is a precursor to benzoisoquinoline alkaloids and is present in other Papaveraceae. S-stylopine is bitter and deters insects and animals from eating the plant. Papaverine is an antifungal precursor to thebaine, common in fire-adapted plants in this family.

Compared with other plants from the nearby area on the Green Trail, including Wooly Blue Curls and Yerba Santa, Tree Poppy rootzone soil samples showed a higher proportion of reads from Actinomycetales. When compared with Coast Live Oak rootzone samples from the Gold Creek Preserve, Tree Poppy soil samples reflected elevated copies of mycothiol production genes in the metagenomic data, based on STAMP output. In the next steps, we will map secondary metabolite genes to closely related species from Papaveraceae and analyze the potential for the production of related compounds by rootzone bacteria.

Basil is an important aromatic plant largely used in medicine and for the preparation of traditional dishes in the Mediterranean area. The purpose of this work was to compare two closed soilless cultivation systems—aeroponics and a pot system—in terms of the quality, shelf-life and yield of the sweet basil (Ocimum basilicum L.) they produced, which is grown in an all-year-round production site in Pisa, Tuscany (Italy). The content of total chlorophylls, carotenoids, total phenols, antioxidant capacity, and rosmarinic acid content, as well as a post-harvest storage analysis, were investigated in fresh-cut sweet basil from both cultivation systems. Numerous postharvest tests have been carried out during each season (spring, summer, autumn, winter), evaluating the quality of the basil after its packaging and storage in a fridge at about 6-8°C in the dark on different days after harvest (3, 6 and 9 days), simulating the normal commercial cycle of fresh-cut sweet basil in supermarkets. Our study showed that sweet basil plants cultivated in aeroponics produced almost double the yield for the same area, with a better water use efficiency (WUE), and had a higher shelf-life in comparison with basil grown in pots in the same periods and with the same climatic conditions. Tests of post-harvest production in sweet basil have shown that the quality obtained by the aeroponic system was similar or sometimes higher compared to that of pot cultivation. Nitrates, on the other hand, tended to be higher in the pots cultivated in spring; however, the values ​​were lower than the maximum limits indicated by the European Food Safety Authority (EFSA). The aeroponic cultivation system tested provided a good qualitative–quantitative production of sweet basil across the four seasons. The aeroponic system, like all closed soilless cultivation systems, has the advantage of increasing production compared to cultivation in a substrate, with a higher water and fertiliser use efficiency and the advantage of not producing exhausted substrate at the end of the cultivation cycle.

The genus Cucurbita includes fourteen species, of which only three are cultivated on a global scale: Cucurbita maxima and C. moschata, commonly referred to as ‘pumpkins’, and C. pepo, known as courgettes. It is estimated that approximately 40% of global agricultural food production losses are due to pests and diseases. Among these, viruses, fungi, and nematodes are the most prevalent emerging threats worldwide.

The objective of this study was to analyse the commercial cultivars of the Cucurbita genus, focusing on quantifying their resistance to diseases caused by viruses and pests. Additionally, this analysis connected these resistance levels to the specific diseases that limit their production. To achieve this, data were collected from the 2023 edition of the Portagrano manual.

According to our analysis, 56% of the varieties of Cucurbita sp. that are available on the market do not have resistance to any disease. Based on typology, squash varieties that are destined for consumption have the highest number of cultivars with no genetic resistance (84%), while 90.6% of rootstock varieties and 74.4% of courgettes are resistant to some disease. Of all the commercially available courgette varieties, 69.2% have resistance to one or more viruses, while this percentage decreases considerably for pumpkins (9.2%) and rootstocks (3.2%). Resistance to fungal diseases is found in the majority in commercial rootstock varieties (93.3%). Fungal resistance is present in 55.2% of courgettes and 7.5% of pumpkins, but in the case of courgettes, it is mainly intermediate resistance to powdery mildew. Resistance to nematodes of the genus Meloidogyne is only found in 6.5% of the cultivars of Cucurbita sp. intended for use as rootstocks.

Among the virus-resistant cultivars, the majority are resistant to zucchini yellow mosaic virus (ZYMV), watermelon mosaic virus (WMV), and cucumber mosaic virus (CMV), with resistance rates of 69.54%, 55.75%, and 33.33%, respectively. Resistance to papaya ring spot virus (PRSV) and tomato yellow curl leaf virus (ToLCNDV) is less common, at 16.67% and 2.30%, respectively. Developing resistant varieties is a crucial strategy for crop improvement. Breeding for virus resistance can significantly mitigate the impact of diseases on cucurbit crops, leading to higher yields and enhanced sustainability. This approach also fosters a more resilient agricultural system, particularly in the face of changing environmental conditions. Our findings underscore the urgent need for increased investment in the improvement of courgettes and pumpkins to promote sustainable crop development.

Acknowledgements: This work was supported by project AVA2023.019, co‐financed by FEDER .

Papaya (Carica papaya L.) is a highly valued tropical fruit. However, its sensitivity to environmental stress, particularly temperature fluctuations, poses a significant challenge to its successful cultivation. This preliminary study assesses the responses to regulated root-zone temperature in papaya seedlings planted under controlled conditions during initial growth and survival. This research study was conducted at the Institute of Sustainable Agrotechnology (INSAT), Universiti Malaysia Perlis (UniMAP), Malaysia, using papaya seedlings grown under three different temperature treatments: ambient conditions (T0), moderate heat (±30°C, T1), and high heat (±45°C, T2). The experiment employed a Completely Randomized Design (CRD), with growth parameters, including survival rate, shoot and root dry weights, and root-to-shoot ratio, assessed over a 16-day period. The results revealed that papaya seedlings exhibited the highest survival rates under ambient conditions (T0), whereas exposure to ±30°C (T1) resulted in a gradual decline in survival, suggesting an adaptive response to moderate heat stress. However, seedlings exposed to ±45°C (T2) experienced complete mortality within five days, highlighting their extreme sensitivity to high-temperature stress. Biomass allocation analysis showed that seedlings under moderate heat (T1) exhibited a significantly higher root-to-shoot ratio compared to the control (P = 0.05), indicating a potential stress-induced adaptation mechanism that favors root growth under elevated temperatures. Despite this, overall shoot and root dry weights did not differ significantly between T0 and T1. This study highlights the susceptibility of papaya seedlings to heat stress during early growth conditions. While moderate heat (±30°C) may enhance root development, excessive temperatures (±45°C) are detrimental to seedling survival, suggesting a narrow thermal threshold for early-stage papaya growth. The findings provide valuable insights into temperature management strategies for papaya cultivation, contributing to improved propagation techniques under changing climatic conditions. Further studies are warranted to explore the physiological and molecular responses of papaya seedlings to temperature stress, which could aid in developing more resilient cultivation practices in the face of climate change.

Groundnut (Arachis hypogea L.) is a significant oilseed crop with high market demand in Bangladesh. However, its production is significantly hampered by abiotic stresses, including soil acidity, which is a major constraint in the Greater Sylhet region of Bangladesh. Acidic soils significantly constrain groundnut productivity by limiting nutrient availability and inducing toxicities, particularly of aluminum and manganese. Identifying genotypes with superior adaptation to acidic conditions is critical for sustaining yield and improving crop resilience. This study aimed to evaluate the performance of diverse groundnut genotypes under acidic soil conditions through morphological and genetic analysis. This study evaluated the performance of ten groundnut varieties under acidic soil conditions at the Regional Agricultural Research Station, BARI, Akbarpur, Moulvibazar, Bangladesh, during the Rabi seasons of 2021-22 (Y1) and 2022-23 (Y2). A randomized complete-block design with three replications was employed. The results revealed significant variations among genotypes in their adaptability to acidic conditions, with certain lines exhibiting superior growth performance and yield stability. The analysis of variance (ANOVA) revealed significant varietal differences in most traits across both years, including in plant height, root length, branches per plant, pods per plant, and yield components. Pearson correlation analysis highlighted strong positive associations between root length and fresh/dry stover yield, as well as pods per plant and pod yield per plant, underscoring their role in enhancing yield potential. Negative correlations were observed between harvest index and dry stover yield, indicating that high biomass production may reduce harvest efficiency. Principal component analysis (PCA) grouped the genotypes based on their yield and yield-related traits, identifying Basanti (DG-2), BARI Chinabadam-6, and BARI Chinabadam-9 as the top-performing varieties across both years. This comprehensive approach not only elucidates the morphological and genetic responses of groundnuts to acidic soil but also serves as a foundation for breeding and developing highly resilient varieties. These improved cultivars will be better equipped to thrive in acid-prone regions, ultimately enhancing productivity and sustainability in such challenging environments in Bangladesh.

Citrus Huanglongbing (HLB) is the most devastating disease affecting citrus trees, primarily transmitted by the citrus psyllid. Once infected, citrus trees develop mottled yellowing symptoms, and the disease can only be managed by removing and destroying infected trees. This has caused severe economic losses to the global citrus industry. HLB is caused by the phloem-limited bacteria Candidatus Liberibacter asiaticus (CLas). However, the pathogenic mechanism of this disease currently remains unclear. Heavy metal-associated isoprenylated plant proteins (HIPPs) are known to be susceptible genes in plant–pathogen interaction systems and play a crucial role in maintaining heavy metal homeostasis and in responding to biotic and abiotic stresses. Previous studies have shown that citrus HIPP are potential susceptible targets of CLas, with multiple HIPP genes being activated in response to CLas infection. To investigate the function of the HIPP gene family in plant immunity, we used three PCR primers and real-time quantitative PCR to identify T-DNA insertion mutants of the Arabidopsis thaliana HIPP genes. Reactive oxygen species (ROS) and callose deposition triggered by flg22 in T-DNA mutants were analyzed by DAB staining and aniline blue staining. The PCR results showed that six pure mutants with T-DNA insertion were identified, with a downregulated expression level of HIPP genes. Furthermore, the DAB staining results indicated that the ROS triggered by flg22 were not influenced in HIPP gene T-DNA mutants. The aniline blue staining results showed that callose deposition was significantly increased in the HMP1T1, HMP52T, and HIPP22T mutants, while callose deposition was significantly decreased in HIPP3T. These findings suggest that HMP1, HMP52, and HIPP22 of Arabidopsis thaliana may act as negative regulators of plant immunity, whereas the HIPP3 gene may function as a positive regulator. This study provides an experimental basis for further functional analysis of HIPP genes in citrus–CLas interactions and plant immunity.

Copper (Cu) is an essential trace element that plays a vital role in various physiological processes in plants. Due to its significance, copper oxide (CuO) nanoparticles (NPs) are increasingly being incorporated into fertilizers as an alternative to traditional forms. However, there is a limited understanding of how CuO NP spraying and light conditions affect plants, particularly leafy vegetables grown hydroponically indoors. This study aimed to evaluate the impact of different LED lighting spectra and CuO NP spraying on the growth and antioxidant potential of Swiss chard (Beta vulgaris var. cicla, ‘Barese’). The plants were cultivated in hydroponic systems using two types of lighting: a red and blue spectrum (R90%:B10%) and a white, red, and blue spectrum (W65%:R30%:B5%), with an intensity of 250 ± 5 μmol m^-2 s^-1. The plants were sprayed with an aqueous suspension of CuO NPs at a concentration of 30 ppm (size 40 nm). Various growth parameters—such as fresh weight, dry weight, and leaf area—were measured, along with antioxidant indices. The results indicated that CuO NPs positively influenced plant growth under white, red, and blue (WRB) illumination, but had no effect under red and blue (RB) illumination. Cu accumulation was higher under RB illumination, yet it remained within safe limits. In terms of antioxidant capacity, RB illumination enhanced DPPH, ABTS, and FRAP values compared to WRB; however, significant effects of CuO NPs were only observed for DPPH (with RB) and FRAP (with WRB). CuO NPs did not significantly impact the total phenolic content, although this content was higher under WRB illumination. This study found varying effects of CuO NPs on antioxidant enzymes: ascorbate peroxidase, monodehydroascorbate reductase (MDHAR), and superoxide dismutase increased under RB illumination, while glutathione reductase, MDHAR, dehydroascorbate reductase, and catalase increased under WRB. In conclusion, the findings suggest that CuO NPs positively influence the growth of Swiss chard and enhance its antioxidant system, particularly under WRB LED illumination.

Introduction

Xylella fastidiosa (Xf) is a Gram-negative bacterium (Janse & Obradovic, 2010: https://www.jstor.org/stable/41998754) that affects numerous plant species, including olive trees, and causes Olive Quick Decline Syndrome (OQDS) . Xf obstructs water and nutrient transport by colonizing the xylem vessels, leading to canopy desiccation and plant death. Despite severe damage, olive trees often produce basal shoots, or suckers, which represent a survival mechanism with a peculiar behavior in Xf-positive plants (Camposeo et al., 2022: https://doi.org/10.3390/agronomy12122917; Martelli, 2016: https://doi.org/10.1007/s12600-015-0498-6).

Goals

The most common reason for the development of suckers is the abandonment of fields, which favors the natural growth processes of the olive tree. These shoots may also represent a survival mechanism as the damaged tree tries to resist by producing suckers. This study aims to determine whether olive tree suckers exhibit enhanced defense mechanisms against Xf by analyzing sucker samples of different ages from three cultivars: Cellina di Nardò, Ogliarola, and Leccino.

Methodology

Four suckers from at least five plants per cvs were collected. Samples were cut from the sucker bases using a sterilized scissors. Approximately 1 g of tissue per sample was homogenized in extraction bags (BIOREBA, Switzerland) with 5 mL of CTAB buffer using a semi-automatic homogenizer (Homex 6, BIOREBA). DNA extraction followed the EPPO Bulletin (2004) (doi:10.1111/epp.12575), employing chloroform for protein removal and ethanol for precipitation. Real-time PCR was performed following Harper et al. (2010) (https://doi.org/10.1094/PHYTO-06-10-0168), and bacterial concentration, expressed as CFU/mL, was estimated according to D’Attoma et al. (2019) (https://doi.org/10.3390/pathogens8040272).

Results

Xf-incidence in suckers of Cellina di Nardò less than 5 years old was approximately 70%, with bacterial loads varying between 10³ to 10⁶ CFU/mL. These values slightly differed from those of the Ogliarola, in which more than two-thirds of the samples were negative in less than 5-year-old-suckers, while Xf-incidence reach 90% in older ones. The bacterial load in Ogliarola is also similar to Cellina, between 10³ and 10⁷ CFU/mL. Conversely, for Leccino, the younger shoots were mainly negative, while those older than 5 years were mostly positive with a bacterial count between 10⁴ and 10⁶ CFU/mL.

Conclusion

The findings highlight age-related and cultivar-dependent variability in Xf susceptibility among olive suckers. Younger suckers generally exhibited lower infection rates, suggesting a form of temporary resistance, but infection seems to progress as expected in older ones. Further research should explore additional factors, such as endophyte presence, to elucidate their potential role in sucker resistance.