Biology subjects

Carretero, Y.

Publications and source records attributed to Carretero, Y..

4 recordsLinked to original sources

bioRxiv2024

New QTLs involved in the control of stigma position in tomato

The tomato mating system was strongly affected by domestication events. Mutations disrupting self-incompatibility paralleled by changes retracting the stigma position (SP) within the staminal cone conferred strict autogamy and self-fertility to the cultivated forms. Although major genes affecting these changes have been identified, SP control in domesticated forms retaining a non-inserted or a heat-inducible SP needs elucidation. To widen the possibility of identifying SP genetic determinants, we analysed the trait in four populations (two germplasm collections, a multiparental recombinant inbred and a biparental progeny) under different environmental conditions (normal and heat stressed). Overall, 36 markers significantly associated with the trait were discovered. Several co-localizations were found, both among regions firstly reported in this work and among them and previously reported positions. This supported the reliability of the analysis. Three of such regions, in the long arms of chromosome 1, 8 and 11, were validated in an independent segregating population and candidate genes in confidence intervals were identified among transcription factors and hormone, stress and cell-wall-related genes. In conclusion, the work supported the hypothesis that the SP phenotype is controlled by different key-genes in tomato, paving the way to identifying novel players and novel mechanisms involved in the regulation of herkogamy. HighlightThe study of three germplasm collections in tomato allowed the identification new significant markers for the stigma position trait while confirmed several previously reported QTLs.

plant biology↗

bioRxiv2024

Characterization of a major QTL for sodium accumulation in tomato shoot

Soil salinity is a serious concern for tomato culture, affecting both yield and quality parameters. Although some genes involved in tomato salt tolerance have been identified, their genetic diversity has been rarely studied. In the present study, we assessed salt tolerance-related traits at juvenile and adult stages in a large core collection and identified salt tolerance QTLs by genome-wide association study (GWAS). The results suggested that a major QTL is involved in leaf sodium accumulation at both physiological stages. We were able to identify the underlying candidate gene, a well-known sodium transporter, called SlHKT1.2. We showed that an eQTL for the expression of this gene colocalized with the sodium content QTL. A polymorphism putatively responsible for its variation was identified in the gene promoter. Finally, to extend the applicability of these results, we carried out the same analysis on a test-cross panel composed of the core collection crossed with a distant line. The results indicated that the identified QTL retained its functional impact even in a hybrid genetic context: this paves the way for its use in breeding programs aimed at improving salinity tolerance in tomato cultivars. Summary statementThe genetic diversity of sodium accumulation in tomato shoot under salt stress is associated with an expression QTL of SlHKT1.2. This gene, already identified as involved in tomato salinity tolerance, has been differentially selected during domestication and is of interest for the development of salinity-tolerant varieties.

plant biology↗

bioRxiv2023

Integration of QTL and transcriptome approaches for the identification of genes involved in tomato response to nitrogen deficiency

Optimising plant nitrogen (N) usage and inhibiting N leaching loss in the soil-crop system is crucial to maintain crop yield and reduce environmental pollution. This study aimed at identifying quantitative trait loci (QTL) and differential expressed genes (DEGs) between two N treatments in order to list candidate genes related to nitrogen-related contrasting traits in tomato varieties. We characterised a genetic diversity core-collection (CC) and a multi-parental advanced generation intercross (MAGIC) tomato population grown in greenhouse under two nitrogen levels and assessed several N-related traits and mapped QTLs. Transcriptome response under the two N conditions was also investigated through RNA sequencing of fruit and leaves in four parents of the MAGIC population. Significant differences in response to N input reduction were observed at the phenotypic level for biomass and N-related traits. Twenty-seven (27) QTLs were detected for three target traits (Leaf N content, leaf Nitrogen Balance Index and petiole NO3- content), ten and six at low and high N condition, respectively; while 19 QTLs were identified for plasticity traits. At the transcriptome level, 4,752 and 2,405 DEGs were detected between the two N conditions in leaves and fruits, respectively, among which 3,628 (50.6%) in leaves and 1,717 (71.4%) in fruit were genotype specific. When considering all the genotypes, 1,677 DEGs were shared between organs or tissues. Finally, we integrated DEGs and QTLs analyses to identify the most promising candidate genes. The results highlighted a complex genetic architecture of N homeostasis in tomato and novel putative genes useful for breeding improved-NUE tomato. HighlightTomato response to nitrogen deficiency is genetically controlled by a few QTLs and impacts the expression of a large number of genes, among which some are good targets for breeding sober varieties.

plant biology↗

bioRxiv2020

Genetic basis of phenotypic plasticity and genotype x environment interaction in a multi-parental population

Deciphering the genetic basis of phenotypic plasticity and genotype x environment interaction (GxE) is of primary importance for plant breeding in the context of global climate change. Tomato is a widely cultivated crop that can grow in different geographical habitats and which evinces a great capacity of expressing phenotypic plasticity. We used a multi-parental advanced generation intercross (MAGIC) tomato population to explore GxE and plasticity for multiple traits measured in a multi-environment trial (MET) design comprising optimal cultural conditions and water deficit, salinity and heat stress over 12 environments. Substantial GxE was observed for all the traits measured. Different plasticity parameters were estimated through the Finlay-Wilkinson and factorial regression models and used together with the genotypic means for quantitative trait loci (QTL) mapping analyses. Mixed linear models were further used to investigate the presence of interactive QTLs (QEI). The results highlighted a complex genetic architecture of tomato plasticity and GxE. Candidate genes that might be involved in the occurrence of GxE were proposed, paving the way for functional characterization of stress response genes in tomato and breeding for climate-adapted crop. HighlightThe genetic architecture of tomato response to several abiotic stresses is deciphered. QTL for plasticity and QTL x Environment were identified in a highly recombinant MAGIC population.

plant biology↗