Differential response to calcium-labelled (44Ca) uptake and allocation in two peach rootstocks in relation to transpiration under in vitro conditions

Calcium-labelled (44Ca) uptake and transport under in vitro GreenTray® temporary immersion bioreactor conditions have been studied related to aeration conditions. For this aim, Rootpac®-20 (RP-20) and Garnem® (G × N) were selected as two main rootstocks used in peach production. Two transpiration conditions, aerated and unaerated, were established for each plant material. 44Ca location, plant development and foliar stomata surface were measured after the in vitro culture period. The results showed that aeration improved Ca transport within the shoot, but it did not enhance Ca uptake by the roots. Regarding plant material, G × N presented a better Ca uptake capacity and concentration. The findings suggest that Ca uptake in the roots is a precise process that is influenced by transpiration. However, it was observed that transpiration and thus the water flux is not the only force promoting Ca uptake by roots. Furthermore, the transport of Ca to the shoot was primarily determined by transpiration, indicating that water flux plays a crucial role in the aboveground movement of Ca. The study also revealed distinct behaviors in Ca uptake and allocation between the different peach rootstocks, emphasizing the importance of considering these factors in the selection process of rootstocks. These findings contribute to our understanding of the mechanisms involved in Ca uptake and transport in peach rootstocks under in vitro conditions. They provide valuable insights for rootstock selection processes and highlight the need for further research in this area

Developing perennial wildflower strips for use in Mediterranean orchard systems

To support sustainable food production and the delivery of ecosystem services through ecological intensification, wildflower strips have become a popular strategy. Despite their success in temperate orchard systems, they remain understudied in Mediterranean ecosystems, which poses a significant barrier to uptake. In order to further promote their adoption, seed mixes must be optimised for commercial orchard systems and for the Mediterranean climate. Plant species should be selected for their consistent performance, whilst the availability of resources for ecosystem service providers determines the quality of the wildflower strip. In this study, the suitability of 12 native perennial forbs and two tussock-forming grass species for wildflower strips in commercial Citrus orchards was assessed over a 3-year period. Distinct resources for natural enemies according to the different plant growth stages were used an indicator of wildflower strip quality. The wildflower strips were managed under two different cutting strategies: (I) standard management, in which wildflower strips were cut once annually in February, and (II) active management, in which wildflower strips were cut two additional times each year. The establishment and success of the sown species were compared. The influence of wildflower strips and their management on plant species richness, community structure, and the provision of resources was compared with a control treatment, in which alleyways were managed conventionally by cutting any naturally occurring vegetation to a height of ≤5 cm, four to five times annual. For the first time, the performance of native perennial plant species has been assessed in Mediterranean orchard systems and a seed mix developed for targeting pest regulation services. The wildflower strips were successful in increasing plant species richness and the available resources expected to support natural enemies. However, only wildflower strips managed with cutting once annually enhanced vegetation cover relative to the control, whilst extending the flowering period. This study therefore provides crucial tools for the further development of sustainable approaches to food production in Mediterranean orchard systems

Editorial: New insights into mechanisms of epigenetic modifiers in plant growth and development. Volume II

As we have learned, chromatin modifications, including histone modifications and DNA methylation, play a key role in plant development (Ng and Bird, 1999). However, accumulated evidence shows that, besides chromatin biochemical modifications, other epigenetic regulations such as chromatin architecture also function at a pivot point to regulate plant development (Zhang et al., 2021). In this Research Topic, five research papers describe multiple developmental facets mediated by different epigenetic mechanisms besides histone modifications. These manuscripts report experimental evidence or summarize recent advances in epigenetic regulations of some important developmental genes or development-related mechanisms. This Research Topic allows readers to learn of the latest advances in epigenetic regulations on seed germination, flowering time control, miRNA biogenesis and stability, secondary meristem maintenance as well as histone deacetylase 9 mediated day-length dependent hypocotyl cell elongation

Bioinformatics approach for developing a minimum set of SNP markers for identification of temperate japonica rice varieties cultivated in Spain

The use of molecular markers for plant variety identification and protection is increasing. For this purpose, SNP markers have provided a reliable and stable tool for plant genotyping. The availability of small and low-cost SNP panels to accelerate the identification of the cultivated rice varieties should be beneficial for breeders, seed certification entities and rice industry. With the intention of providing of such a facility, we first developed a simple and easy-handle bioinformatics tool based on the widely used and freely available software R to generate small sets of SNPs that can discriminate varieties, by selecting markers from a larger genotyping dataset. By applying this algorithm to data from a previously genotyped collection of temperate japonica varieties from different countries, we identified a minimal set of 31 SNPs markers to distinguish 210 varieties. In addition, we used this algorithm to discriminate the 43 most cultivated in Spain rice varieties with minimal sets of 8 SNPs. We then developed and tested 22 Kompetitive Allele-Specific PCR (KASP) assays for the markers included in these panels, and obtained reliable genotype patterns for rice varieties identification. The complete 22 markers panel and the rice genotypes data could offer a useful and low-cost tool for rice breeders and industry to identify varieties and therefore to guarantee the quality of rice. The provided R-based algorithm can be applied to other genomic resources to develop core sets of discriminating markers

Comparative Analysis of Primary and Secondary Metabolites in the Peel of Eight Blood Orange Varieties

The global cultivation of blood oranges is experiencing an increase due to their remarkable nutritional properties. Blood orange by-products, especially the peel, have a high concentration of bioactive compounds with exceptional antioxidant potential, making them an ideal choice for incorporation into various food products. This study aimed to determine the morphological parameters and primary and secondary metabolite content of peel of eight blood orange varieties using 1H NMR and HPLC-ESI-DAD-MSn. “Tarocco Meli” had the highest weight (367.83 g), caliber (94.13 mm and 88.87 mm), peel thickness (6.73 mm), and peel weight (155.0 g). “Tarocco Rosso”, “Sanguinelli”, and “Tarocco Gallo” had the highest levels of total amino acids (25.57 g kg−1 DW), total organic acids (29.99 g kg−1 DW), and total sugars (68.56 g 100 g−1 DW), respectively. The peel of “Moro” had significantly higher concentrations of total anthocyanins, hydroxycinnamic acids, and flavones (650.67, 263.33, and 449.85 mg kg−1, respectively) compared to the other varieties. In conclusion, “Tarocco Meli” had the most interesting values for morphological parameters, “Tarocco Rosso”, “Sanguinelli”, and “Tarocco Gallo” for primary metabolites, and “Moro” for secondary metabolites. With the increasing interest in utilizing co-products, these findings could be useful in developing functional food products that meet consumer demands for healthier and more sustainable food choices

Detecting abandoned citrus crops using Sentinel-2 time series. A case study in the Comunitat Valenciana region (Spain)

Agricultural land abandonment (ALA) is becoming a growing phenomenon around the world that needs to be monitored and quantified. A massive abandonment of citrus orchards has been experienced in the last years in the Comunitat Valenciana (CV) region (Spain) driven by different socio-economic factors. Therefore, developing time and cost-efficient methods for monitoring ALA is a priority. Citrus are a perennial crop trees which make orchards have low spectral variation during the year. In the CV region, they are planted in relatively small parcels, thus creating a highly fragmented and heterogeneous landscape. This study proposes a machine learning-based classification framework that uses annual time series of spectral indices extracted from Sentinel-2 images to identify crop status at parcel level. The method is based on features extracted from the reconstructed OSAVI and NDMI time series used to train a Random Forest classifier. Then, a parcel-based classification is performed using the parcel boundaries and the probabilities of belonging to each category for the full pixels inside the boundaries. The research assessed the potential to identify three statuses of crops (non-productive, productive, and abandoned). Results on three different temporal and spatial datasets provided an overall accuracy ranging from 89 to 92 %, demonstrating the importance of multi-temporal data to identify the abandonment of perennial crops. Furthermore, we studied the ability of the model to be spatially and temporally transferred. Limitations to recall the abandoned parcels when using models trained in other areas or time periods are exposed, opening the way to model improvements

Un nuevo enfoque sostenible de gestión de plagas y enfermedades a través de la inducción de defensas de las plantas

Las plantas son capaces de activar defensas en respuesta al ataque de herbívoros. Estas defensas pueden ser directas o indirectas, y pueden aprovecharse para su integración en programas de gestión sostenible de plagas y enfermedades. En estudios realizados por el IVIA, se ha demostrado que la exposición de plantas de tomate, pimiento y cítricos a varios volátiles inducidos por herbivoría (HIPV’s) aumentan la sobreexpresión de genes defensivos en comparación con plantas no expuestas. De estos volátiles, se ha seleccionado el (Z)-3-hexenil propanoato [(Z)-3-HP] por su capacidad para activar diversas rutas defensivas en los tres cultivos. Además, se ha confirmado que la exposición a (Z)-3-HP aumenta la producción de compuestos derivados de ácidos grasos y la acumulación de compuestos de defensa específicos. Para su aplicación práctica, y en colaboración con el grupo del CEQA de la UPV, se diseñaron difusores poliméricos de liberación controlada que son capaces de emitir (Z)-3-HP a tasas constantes durante períodos prolongados y que ya han sido probados en condiciones de campo en los tres cultivos mencionados. Los resultados obtenidos sugieren que el uso de HIPV’s puede ser una estrategia prometedora para la gestión sostenible de plagas y enfermedades en agricultura

Ensayo de cultivares de alcachofa (Cynara scolymus l.) en dos ciclos de cultivo

La aparición en el mercado de nuevos cultivares de alcachofa reproducidos mediante semilla hace necesario el análisis de las características agronómicas de cada uno de ellos, así como la adaptación de estos materiales a nuestra zona de cultivo. En este trabajo estudiamos 10 cultivares de alcachofa procedentes de semilla por campaña, durante dos campañas, 2018-19 y 2019-20. De estos, 7 cultivares se repitieron en los dos ensayos y tres se cambiaron, por lo que finalmente analizamos un total de 13 cultivares diferentes. Como testigos empleamos Blanca de Tudela y Calicó, multiplicados por zueca, que son los cultivares empleados tradicionalmente por nuestros agricultores. También estudiamos la influencia que ejerce sobre su ciclo productivo la aplicación de ácido giberélico (AG3), ya que sabemos por trabajos previos que sin el empleo de dicha hormona se retrasa mucho la entrada en producción. Para este trabajo diseñamos un ensayo de bloques al azar con dos repeticiones por tratamiento con aplicación de ácido giberélico y otras dos repeticiones sin tratamiento como testigo

Induction of glandular trichomes to control whitefly-transmitted viruses in tomato crops: modulation by the natural enemy Nesidiocoris tenuis

Whitefly-transmitted viruses are one of the biggest threats to tomato growing worldwide. Strategies based on the introgression of resistance traits from wild relatives are promoted to control tomato pests and diseases. Recently, a trichome-based resistance characterizing the wild species Solanum pimpinellifolium was introgressed into a cultivated tomato. An advanced backcross line (BC5S2) exhibiting the presence of acylsugars-associated type IV trichomes, which are lacking in cultivated tomatoes, was effective at controlling whiteflies (Hemiptera: Aleyrodidae) and limiting the spread of whitefly-transmitted viruses. However, at early growth stages, type IV trichomes density and acylsugars production are limited; thus, protection against whiteflies and whitefly-transmitted viruses remains irrelevant. In this work, we demonstrate that young BC5S2 tomato plants feeding-punctured by the zoophytophagous predator Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) displayed an increase (above 50%) in type IV trichomes density. Acylsugars production was consistently increased in N. tenuis-punctured BC5S2 plants, which was more likely associated with upregulated expression of BCKD-E2 gene related to acylsugars biosynthesis. In addition, the infestation of BC5S2 plants with N. tenuis effectively induced the expression of defensive genes involved in the jasmonic acid signaling pathway, resulting in strong repellence to B. tabaci and attractiveness to N. tenuis. Thus, by pre-plant release of N. tenuis in tomato nurseries carried out in some integrated pest management programs, type IV trichome-expressing plants can be prepared to control whiteflies and whitefly-transmitted viruses at early growth stages. This study emphasizes the advantage of reinforcing constitutive resistance using defense inducers to guarantee robust protection against pests and transmitted viruses

In vivo rabbit embryo production and cryopreservation review. Application to ex situ conservation and rederivation

The development of reproductive technologies in this species is contributing decisively to the development of rabbit farming and the preservation of genetic resources. Obtaining embryos is an essential step to both genetic diffusion and the preservation of genetic resources from genetic erosion or natural disasters. In rabbits, it is common for embryos to be recovered post-mortem after ovarian hyperstimulation with gonadotrophins, although the quality and number of embryos are variable, affecting the embryo viability and offspring rate by the donor. In vivo embryo production within a conservation programme aims not only to obtain a large number of embryos, but also that they come from a greater number of male and female origins, in order to ensure an adequate representation of the original population. This is why both the quality and quantity of embryos obtained per donor rabbit and the rate of donors with offspring after embryo cryopreservation must be considered, as well as the response of the embryos to the chemical, physical and physiological stress to which they are subjected in the rederivation process and its postnatal repercussions on those that survive. Rederived rabbits from cryopreserved and transferred embryos showed phenotypic growth changes, which calls into question the neutrality of the technique and its usefulness in those cases in which a control population is required