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Nizan S, Amitzur A, Dahan-Meir T, Benichou JIC, Bar-Ziv A, Perl-Treves R. Mutagenesis of the melon Prv gene by CRISPR/Cas9 breaks papaya ringspot virus resistance and generates an autoimmune allele with constitutive defense responses. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4579-4596. [PMID: 37137337 PMCID: PMC10433930 DOI: 10.1093/jxb/erad156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 05/02/2023] [Indexed: 05/05/2023]
Abstract
The majority of plant disease resistance (R) genes encode nucleotide binding-leucine-rich repeat (NLR) proteins. In melon, two closely linked NLR genes, Fom-1 and Prv, were mapped and identified as candidate genes that control resistance to Fusarium oxysporum f.sp. melonis races 0 and 2, and to papaya ringspot virus (PRSV), respectively. In this study, we validated the function of Prv and showed that it is essential for providing resistance against PRSV infection. We generated CRISPR/Cas9 [clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein 9] mutants using Agrobacterium-mediated transformation of a PRSV-resistant melon genotype, and the T1 progeny proved susceptible to PRSV, showing strong disease symptoms and viral spread upon infection. Three alleles having 144, 154, and ~3 kb deletions, respectively, were obtained, all of which caused loss of resistance. Interestingly, one of the Prv mutant alleles, prvΔ154, encoding a truncated product, caused an extreme dwarf phenotype, accompanied by leaf lesions, high salicylic acid levels, and defense gene expression. The autoimmune phenotype observed at 25 °C proved to be temperature dependent, being suppressed at 32 °C. This is a first report on the successful application of CRISPR/Cas9 to confirm R gene function in melon. Such validation opens up new opportunities for molecular breeding of disease resistance in this important vegetable crop.
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Affiliation(s)
- Shahar Nizan
- The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Israel
| | - Arie Amitzur
- The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Israel
| | - Tal Dahan-Meir
- Plant and Environmental Sciences, Weizmann Institute of Science, Israel
| | | | - Amalia Bar-Ziv
- The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Israel
| | - Rafael Perl-Treves
- The Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Israel
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Noris E, Pegoraro M, Palzhoff S, Urrejola C, Wochner N, Kober S, Ruoff K, Matić S, Schnepf V, Weisshaar N, Wege C. Differential Effects of RNA-Dependent RNA Polymerase 6 (RDR6) Silencing on New and Old World Begomoviruses in Nicotiana benthamiana. Viruses 2023; 15:v15040919. [PMID: 37112899 PMCID: PMC10143181 DOI: 10.3390/v15040919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/28/2023] [Accepted: 03/30/2023] [Indexed: 04/29/2023] Open
Abstract
RNA-dependent RNA polymerases (RDRs) are key players in the antiviral defence mediated by RNA silencing in plants. RDR6 is one of the major components of the process, regulating the infection of certain RNA viruses. To better clarify its function against DNA viruses, we analyzed the effect of RDR6 inactivation (RDR6i) in N. benthamiana plants on two phloem-limited begomoviruses, the bipartite Abutilon mosaic virus (AbMV) and the monopartite tomato yellow leaf curl Sardinia virus (TYLCSV). We observed exacerbated symptoms and DNA accumulation for the New World virus AbMV in RDR6i plants, varying with the plant growth temperature (ranging from 16 °C to 33 °C). However, for the TYLCSV of Old World origin, RDR6 depletion only affected symptom expression at elevated temperatures and to a minor extent; it did not affect the viral titre. The accumulation of viral siRNA differed between the two begomoviruses, being increased in RDR6i plants infected by AbMV but decreased in those infected by TYLCSV compared to wild-type plants. In situ hybridization revealed a 6.5-fold increase in the number of AbMV-infected nuclei in RDR6i plants but without egress from the phloem tissues. These results support the concept that begomoviruses adopt different strategies to counteract plant defences and that TYLCSV evades the functions exerted by RDR6 in this host.
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Affiliation(s)
- Emanuela Noris
- Institute for Sustainable Plant Protection, National Research Council of Italy, Strada delle Cacce 73, 10135 Torino, Italy
| | - Mattia Pegoraro
- Institute for Sustainable Plant Protection, National Research Council of Italy, Strada delle Cacce 73, 10135 Torino, Italy
| | - Sandra Palzhoff
- Institute of Biomaterials and Biomolecular Systems, Molecular and Synthetic Plant Virology, University of Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - Catalina Urrejola
- Institute of Biomaterials and Biomolecular Systems, Molecular and Synthetic Plant Virology, University of Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - Nicolai Wochner
- Institute of Biomaterials and Biomolecular Systems, Molecular and Synthetic Plant Virology, University of Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - Sigi Kober
- Institute of Biomaterials and Biomolecular Systems, Molecular and Synthetic Plant Virology, University of Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - Kerstin Ruoff
- Institute of Biomaterials and Biomolecular Systems, Molecular and Synthetic Plant Virology, University of Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - Slavica Matić
- Institute for Sustainable Plant Protection, National Research Council of Italy, Strada delle Cacce 73, 10135 Torino, Italy
| | - Vera Schnepf
- Institute of Biomaterials and Biomolecular Systems, Molecular and Synthetic Plant Virology, University of Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - Nina Weisshaar
- Institute of Biomaterials and Biomolecular Systems, Molecular and Synthetic Plant Virology, University of Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
| | - Christina Wege
- Institute of Biomaterials and Biomolecular Systems, Molecular and Synthetic Plant Virology, University of Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany
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