Browsing by Author "Stange, Claudia"

Now showing 1 - 4 of 4
  • No Thumbnail Available
    Item
    Carrot DcALFIN4 and DcALFIN7 Transcription Factors Boost Carotenoid Levels and Participate Differentially in Salt Stress Tolerance When Expressed in Arabidopsis thaliana and Actinidia deliciosa
    (2022) Felipe Quiroz-Iturra, Luis; Simpson, Kevin; Arias, Daniela; Silva, Cristobal; Gonzalez-Calquin, Christian; Amaza, Leticia; Handford, Michael; Stange, Claudia
    ALFIN-like transcription factors (ALs) are involved in several physiological processes such as seed germination, root development and abiotic stress responses in plants. In carrot (Daucus carota), the expression of DcPSY2, a gene encoding phytoene synthase required for carotenoid biosynthesis, is induced after salt and abscisic acid (ABA) treatment. Interestingly, the DcPSY2 promoter contains multiple ALFIN response elements. By in silico analysis, we identified two putative genes with the molecular characteristics of ALs, DcAL4 and DcAL7, in the carrot transcriptome. These genes encode nuclear proteins that transactivate reporter genes and bind to the carrot DcPSY2 promoter in yeast. The expression of both genes is induced in carrot under salt stress, especially DcAL4 which also responds to ABA treatment. Transgenic homozygous T3 Arabidopsis thaliana lines that stably express DcAL4 and DcAL7 show a higher survival rate with respect to control plants after chronic salt stress. Of note is that DcAL4 lines present a better performance in salt treatments, correlating with the expression level of DcAL4, AtPSY and AtDXR and an increase in carotenoid and chlorophyll contents. Likewise, DcAL4 transgenic kiwi (Actinidia deliciosa) lines show increased carotenoid and chlorophyll content and higher survival rate compared to control plants after chronic salt treatment. Therefore, DcAL4 and DcAL7 encode functional transcription factors, while ectopic expression of DcAL4 provides increased tolerance to salinity in Arabidopsis and Kiwi plants.
  • Thumbnail Image
    Item
    Decoding the Hayward kiwi (Actinidia deliciosa var Hayward) genome: transcriptomic responses to drought and salinity and AdhSAP4’s role in salinity stress responses
    (2025) Parra, Samuel; Núñez-Lillo, Gerardo; Tapia-Reyes, Patricio; Carrasco-Lozano, Emerson Clovis; Porcile, Vincenzo; Gonzalez-Calquin, Christian; Amaza, Leticia; Quiroz, Luis Felipe; Meneses Araya, Claudio Antonio; Handford, Michael; Norambuena, Lorena; Martínez, Juan Pablo; Stange, Claudia
    Abiotic stresses such as drought and salinity pose major limitations to crop productivity, particularly in sensitive species like the Hayward kiwi (Actinidia deliciosa var. Hayward). Stress-associated proteins (SAPs), defined by conserved A20/AN1 zinc finger domains, are emerging as key modulators of plant stress responses. Despite their relevance in model plants, their functional roles in kiwi remain unexplored. In this study we assembled a high-quality haploid reference genome for Hayward kiwi, annotating 42,797 protein-coding genes. RNA-Seq profiling of in vitro leaves exposed to drought (20% PEG-6000) and salinity (200 mM NaCl) at 6 and 24 hours identified differentially expressed genes (DEGs). The differential gene expression kinetics between drought and salinity suggest distinct adaptation mechanisms. Fourteen SAP genes were identified, with AdhSAP4 showing salt-induced expression and homology to rice OsSAP7. Nuclear localization of AdhSAP4-GFP was confirmed, and transgenic tobacco lines overexpressing AdhSAP4 exhibited heightened salt sensitivity, reduced growth, and chlorophyll loss. This study establishes a genomic and transcriptomic framework for kiwi stress biology and confirms AdhSAP4 as a negative regulator of salinity tolerance. The evolutionary conservation of SAP function highlights their potential as biotechnological targets for enhancing stress resilience in perennial crops like kiwi.
  • Thumbnail Image
    Item
    Identification of Lycopene epsilon cyclase (LCYE) gene mutants to potentially increase beta-carotene content in durum wheat (Triticum turgidum L.ssp. durum) through TILLING
    (2018) Richaud, Daniela; Stange, Claudia; Gadaleta, Agata; Colasuonno, Pasqualina; Parada, Roberto; Schwember Neira, Andrés R.
  • Thumbnail Image
    Item
    The N-homologue LRR domain adopts a folding which explains the TMV-Cg-induced HR-like response in sensitive tobacco plants
    (ELSEVIER SCIENCE INC, 2008) Stange, Claudia; Matus, Jose Tomas; Dominguez, Calixto; Perez Acle, Tomas; Arce Johnson, Patricio
    Following leaf infection with the tobacco mosaic virus (TMV), Nicotiana species that carry the disease resistance N gene develop a hypersensitive response (HR) that blocks the systemic movement of the virus. TMV-sensitive tobacco plants that lack the N gene develop classical disease symptoms following infection with most of the tobamoviruses. However, upon infection with TMV-Cg, these p, ants display a HR-like response that is unable to limit viral spread. We previously identified the NH gene in sensitive plants; this gene is homologous to the resistance N gene and both belong to the TIR/NBS/LRR family. Isolation and analysis of the NH transcript enabled the prediction of the amino acid sequence in which we detected a leucine-rich repeat domain, proposed to be involved in pathogen recognition. This domain is found in four of five classes of pathogen resistant proteins, in which sequence and structural changes may generate different specificities. In order to study the possible functional role of the LRR domain in the HR-like response, we developed a comparative three-dimensional model for the NH and N gene products, by means of functional and structural domains recognition, secondary structure prediction, domain assignment through profile Hidden Markov Models (HMM) and molecular dynamics (MD) simulations. Based on our results we postulate that the NH protein could adopt a LRR fold with a functional role in the HR-like response. Our two reliable LRR three-dimensional models (N-LRR, NH-LRR) can be used as structural frameworks for future experiments in which the structure-function relationships regarding the protein-protein interaction process may be revealed. Evolutionary aspects of the N and NH genes in Nicotiana species are also discussed. (c) 2007 Elsevier Inc. All rights reserved.