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Švara A, De Storme N, Carpentier S, Keulemans W, De Coninck B. Phenotyping, genetics, and "-omics" approaches to unravel and introgress enhanced resistance against apple scab ( Venturia inaequalis) in apple cultivars ( Malus × domestica). HORTICULTURE RESEARCH 2024; 11:uhae002. [PMID: 38371632 PMCID: PMC10873587 DOI: 10.1093/hr/uhae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 12/27/2023] [Indexed: 02/20/2024]
Abstract
Apple scab disease, caused by the fungus Venturia inaequalis, endangers commercial apple production globally. It is predominantly managed by frequent fungicide sprays that can harm the environment and promote the development of fungicide-resistant strains. Cultivation of scab-resistant cultivars harboring diverse qualitative Rvi resistance loci and quantitative trait loci associated with scab resistance could reduce the chemical footprint. A comprehensive understanding of the host-pathogen interaction is, however, needed to efficiently breed cultivars with enhanced resistance against a variety of pathogenic strains. Breeding efforts should not only encompass pyramiding of Rvi loci and their corresponding resistance alleles that directly or indirectly recognize pathogen effectors, but should also integrate genes that contribute to effective downstream defense mechanisms. This review provides an overview of the phenotypic and genetic aspects of apple scab resistance, and currently known corresponding defense mechanisms. Implementation of recent "-omics" approaches has provided insights into the complex network of physiological, molecular, and signaling processes that occur before and upon scab infection, thereby revealing the importance of both constitutive and induced defense mechanisms. Based on the current knowledge, we outline advances toward more efficient introgression of enhanced scab resistance into novel apple cultivars by conventional breeding or genetic modification techniques. However, additional studies integrating different "-omics" approaches combined with functional studies will be necessary to unravel effective defense mechanisms as well as key regulatory genes underpinning scab resistance in apple. This crucial information will set the stage for successful knowledge-based breeding for enhanced scab resistance.
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Affiliation(s)
- Anže Švara
- Laboratory for Plant Genetics and Crop Improvement, Division of Crop Biotechnics, KU Leuven Plant Institute, Willem de Croylaan 42, 3001 Leuven, Belgium
- KU Leuven Plant Institute, KU Leuven 3001 Leuven, Belgium
| | - Nico De Storme
- Laboratory for Plant Genetics and Crop Improvement, Division of Crop Biotechnics, KU Leuven Plant Institute, Willem de Croylaan 42, 3001 Leuven, Belgium
- KU Leuven Plant Institute, KU Leuven 3001 Leuven, Belgium
| | - Sebastien Carpentier
- Laboratory of Tropical Crop Improvement, Division of Crop Biotechnics, KU Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium
- Genetic resources, Bioversity International, Willem de Croylaan 42, 3001 Leuven, Belgium
- KU Leuven Plant Institute, KU Leuven 3001 Leuven, Belgium
| | - Wannes Keulemans
- Laboratory for Plant Genetics and Crop Improvement, Division of Crop Biotechnics, KU Leuven Plant Institute, Willem de Croylaan 42, 3001 Leuven, Belgium
- KU Leuven Plant Institute, KU Leuven 3001 Leuven, Belgium
| | - Barbara De Coninck
- Laboratory of Plant Health and Protection, Division of Crop Biotechnics, KU Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium
- Laboratory for Plant Genetics and Crop Improvement, Division of Crop Biotechnics, KU Leuven Plant Institute, Willem de Croylaan 42, 3001 Leuven, Belgium
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Comparative transcriptomics unravels new genes imparting scab resistance in apple (Malus x domestica Borkh.). Funct Integr Genomics 2022; 22:1315-1330. [PMID: 35931837 DOI: 10.1007/s10142-022-00889-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 07/21/2022] [Accepted: 07/21/2022] [Indexed: 11/04/2022]
Abstract
Apple scab is caused by an ascomycete fungus, Venturia inaequalis (Cke.) Wint., which is one of the most severe disease of apple (Malus × Domestica Borkh.) worldwide. The disease results in 30-40% fruit loss annually and even complete loss in some places. Owing to the evolving susceptibility of resistant apple genotypes harboring R-genes to new variants of V. inaequalis, a comparative transcriptome analysis using Illumina (HiSeq) platform of three scab-resistant (Florina, Prima, and White Dotted Red) and three susceptible (Ambri, Vista Bella, and Red Delicious) apple genotypes was carried out to mine new scab resistance genes. The study led to the identification of 822 differentially expressed genes in the tested scab-resistant and scab-susceptible apple genotypes. The most upregulated genes uniformly expressed in resistant varieties compared to susceptible ones were those coding for 17.3 kDa class II heat shock protein-like, chaperone protein ClpB1, glutathione S-transferase L3-like protein, B3 domain-containing protein At3g18960-like, transcription factor bHLH7, zinc finger MYM-type protein 1-like, and nine uncharacterized proteins, besides three lncRNAs. The genes that were downregulated in susceptible and upregulated in resistant cultivars were those coding for non-specific lipid transfer protein GPI-anchored 1, rust resistance kinase Lr10-like, disease resistance protein RPS6-like, and many uncharacterized proteins. DESeq2 analysis too revealed 20 DEGs that were upregulated in scab-resistant cultivars. Furthermore, a total of 361 genes were significantly upregulated in scab-susceptible variety, while 461 were found downregulated (P value < 0.05 and Log2 (FC) > 1). The differentially expressed genes (DEGs) were related to various pathways, i.e., metabolic, protein processing, biosynthesis of secondary metabolites, plant hormone signal transduction, autophagy, ubiquitin-mediated proteolysis, plant-pathogen interaction, lipid metabolism, and protein modification pathways. Real-time expression of a set of selected twelve DEGs further validated the results obtained from RNA-seq. Overall, these findings lay the foundation for investigating the genetic basis of apple scab resistance and defense pathways that might have a plausible role in governing scab resistance in apple against V. inaequalis.
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Mir S, Sakina A, Masoodi KZ, Bhat KM, Padder BA, Murtaza I, Nazir N, Bhat ZA, Wani SH, Shikari AB. Mapping of quantitative trait loci for scab resistance in apple (Malus × domestica) variety, Shireen. Mol Biol Rep 2022; 49:5555-5566. [PMID: 35579736 DOI: 10.1007/s11033-022-07488-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Accepted: 04/19/2022] [Indexed: 11/25/2022]
Abstract
BACKGROUND Scab caused by Venturia inaequalis (Cke.) Wint. is the most important fungal disease of apple. Fungicide application is a widely practiced method of disease control. However, the use of chemicals is costintensive, tedious, and ecologically unsafe. The development of genetic resistance and the breeding of resistant cultivars is the most reliable and safest option. One such source of scab resistance happens to be the variety 'Shireen', released from SKUAST-Kashmir. However, to date, the nature of resistance and its genetic control have not been characterized. Objective This research aimed to elucidate the genetic basis of scab resistance in Shireen. METHODS Genetic mapping of quantitative trait loci (QTL) for resistance to apple scab disease was performed using an F1 cross developed between the susceptible cultivar 'StarKrimson' and the resistant cultivar 'Shireen'. The population was evaluated for two consecutive years. Further, six candidate genes were analyzed via quantitative real-time PCR, to determine their expression level in response to the pathogen infestation. RESULTS Genotyping and disease phenotyping of populations led us to identify two quantitative trait loci (QTLs), namely qRVI.SS-LG2.2019 and qRVI.SS-LG8.2019 on chromosomes 2 and 8 with LOD-values of 7.67 and 4.99 respectively, and six potential CDGs for the polygenic resistance in 'Shireen'. The genomic region corresponding to the mapped QTLs in LG 2 and LG 8 of 'Shireen' was examined for candidate genes possibly related to scab resistance using in silico analysis. CONCLUSION The QTLs mapped in the genetic background of Shireen are the novel QTLs and may be transferred to desirable genetic backgrounds and provide opportunities for isolation and cloning of genes apart from their utility to achieve durable resistance to scab.
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Affiliation(s)
- Saba Mir
- Division of Plant Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K), Shalimar, Srinagar, J&K, 190025, India
| | - Aafreen Sakina
- Division of Plant Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K), Shalimar, Srinagar, J&K, 190025, India
| | - Khalid Z Masoodi
- Division of Plant Biotechnology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K), Shalimar, Srinagar, J&K, 190025, India
| | - Khalid M Bhat
- Division of Fruit Science, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K), Shalimar, Srinagar, J&K, 190025, India
| | - Bilal A Padder
- Division of Plant Pathology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K), Shalimar, Srinagar, J&K, 190025, India
| | - Imtiyaz Murtaza
- Division of Basic Sciences and Humanities, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K), Shalimar, Srinagar, J&K, 190025, India
| | - Nagina Nazir
- Division of Agricultural Statistics, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K), Shalimar, Srinagar, J&K, 190025, India
| | - Zahoor Ahmad Bhat
- Division of Plant Pathology, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K), Shalimar, Srinagar, J&K, 190025, India
| | - Shabir H Wani
- MRCFC, KhudwaniSher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K), Srinagar, J&K, 190025, India.
| | - Asif B Shikari
- MRCFC, KhudwaniSher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K), Srinagar, J&K, 190025, India.
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