Miranda Jiménez, Carlos

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Miranda Jiménez

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Carlos

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Agronomía, Biotecnología y Alimentación

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IMAB. Research Institute for Multidisciplinary Applied Biology

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Now showing 1 - 2 of 2
  • PublicationOpen Access
    Assessment of flesh browning diversity in apple germplasm collections phenotyped by image analysis
    (ISHS, 2023) Miranda Jiménez, Carlos; Irisarri, Patricia; Arellano Zapatero, Julia; Bielsa González, Francisco Javier; Valencia Leoz, Ana; Urrestarazu Vidart, Jorge; Pina, Ana; Santesteban García, Gonzaga; Castel, L.; Errea, Pilar; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute for Multidisciplinary Research in Applied Biology - IMAB
    Enzymatic flesh browning (EB) is one of the major problems affecting the quality and limiting the shelf life of minimally processed fruit. Traditionally, EB has been measured objectively using colourimeters. However, colourimeters are not suitable for phenotyping large quantities of fruit samples as they measure just one small area of a sample at a time, which hampers the acquisition of representative measurements and renders them time-consuming and costly. Previous research has shown that image analysis of digital photographs could be a viable alternative to obtain colour information of the entire surface of samples for large scale phenotyping, but to date there are no references for its practical application. The aim of this work was to assess the diversity in EB in a large set of cultivars phenotyped using digital photographs and a high-throughput analytical system based on image analysis developed by our team. A set of 143 cultivars from 104 genotypes, including modern references (16 cultivars) and traditional Spanish cultivars from UPNA (67 cultivars) and CITA (60 cultivars) germplasm collections was analysed in 2020 and 2021. The traditional cultivars were part of the core collection, which optimizes the representativeness of the genetic variation of apples preserved in Spanish collections. EB was evaluated in 10 fruits per cultivar and photographed at regular intervals from just after cutting to one hour later. A wide range of EB intensities was observed, with up to 20-fold differences between cultivars, which could be classified into five levels using two indices. The time at which EB was evaluated (30 or 60 min after slicing) had little influence on the classification. Traditional cultivars with low or very low EB were found to be comparable to those of references with less EB. The results show the potential of traditional germplasm to diversify the varietal offer and introduce new traits in apple breeding.
  • PublicationOpen Access
    Comparative enzymatic browning transcriptome analysis of three apple cultivars unravels a conserved regulatory network related to stress responses
    (BMC, 2025-04-12) Bielsa González, Francisco Javier; Grimplet, Jérôme; Irisarri, Patricia; Miranda Jiménez, Carlos; Errea, Pilar; Pina, Ana; Agronomía, Biotecnología y Alimentación; Agronomia, Bioteknologia eta Elikadura; Institute for Multidisciplinary Research in Applied Biology - IMAB
    Enzymatic browning (EB) endangers the adaptation of apple fruit cultivars to new markets, affecting organoleptic properties and producing economic losses. Polyphenol oxidases and polyphenol compounds play a key role in EB development in apple. However, the regulation of apple response to EB remains to be uncovered. In this study, three apple cultivars with different EB phenotypes ranging from low to high browning in apple pulp were used to study transcriptomic changes over time after fresh cutting (0, 30 and 60 min). This study allowed the identification of 1448 differentially expressed genes (DEGs), revealing both shared and genotype-specific responses, particularly in the affected metabolic pathways associated with EB. At 60 min (T60 vsT0), 77 DEGs were shared by all genotypes, suggesting a conserved regulatory network. This network included genes encoding for protein families such as calcium-binding proteins, heat-shock proteins, redox-responsive transcription factors, WRKY family transcription factors, zinc finger family proteins and disease resistance proteins among others. A co-expressed gene cluster, identified through Weighed Gene Co-Expression Network Analysis (WGCNA), was found to correlate with EB and included 323 genes enriched in several biological terms according to Gene Ontology analysis. Moreover, a more detailed analysis of identified WGCNA gene cluster regulatory sequences allowed the detection of cis-regulatory elements belonging to CAMTA, WRKY and WUSCHEL transcription factor families. The identification of these sequences alongside with an abundant and diverse amount of overexpressed transcription factors from various families (WRKY, ERF, GRAS, GATA, etc.) point out to a highly regulated stress-response that is strictly connected to innate plant immunity. These findings provide valuable insights into the molecular mechanism involved in apple fresh-cut browning and offer new potential targets for EB regulation.