Identification of molecular markers for Sw-5 gene of tomato spotted wilt virus resistance

Abstract

Tomato spotted wilt virus (TSWV) is one of the most destructive viral diseases that threaten worldwide tomato (Solanuum lycopersicum L. syn Lycopersicon esculentum Mill.) production. Use of host resistance appears to be the best way to control the disease. Marker assisted selection (MAS) has become very important and useful in the selection of TSWV resistance genes. The objective of this research was to identify Sw-5 gene-specific PCR-based molecular markers and gene-derived single nucleotide polymorphism (SNP) markers for MAS in tomato breeding. A gene-specific PCR-based marker and two gene-derived SNP markers specific for TSWV resistance Sw5-b allele were identified and validated in different tomato germplasm. It is expected that the present findings will be helpful in advancing the MAS for TSWV resistance in tomato.

Development of a Single-nucleotide Polymorphism Marker for the Sw-5b Gene Conferring Disease Resistance to Tomato spotted wilt virus in Tomato

“…Except for 'TY sense Q' and 'Titichal' that were already described by the provider to carry resistance to TSWV, 'Savera', 'TY tiny', 'Daylose' and 'Shinheuksu' were newly identified as cultivars carrying resistance to TSWV in this study. Previously, Shi et al (2011) also screened 14 tomato accessions and 10 commercial tomato cultivars for TSWVresistance and found that only three commercial cultivars ('Talladega', 'Sophya', and 'BHN-444') and one accession (LA3667) carried the Sw-5b allele for resistance to TSWV as shown in the Stevens cultivar, the original source of the Sw-5b allele for resistance to TSWV. In this study, completely different commercial cultivars from what Shi et al (2011) used were screened, and only six of them were determined to be TSWV-resistant.…”

“…The dominant PCR marker specific to Sw-5b with the primer pair Sw5b-f2/Sw5b-r2 (Table 2) was previously reported (Shi et al, 2011). Collected tomato cultivars were screened by PCR with this primer pair, including the TSWVsusceptible cultivars, Moneymaker and M82.…”

“…For the primer pairs Sw5b-f1/r1 and Sw5b-f2/r2 (Table 2), PCR amplification was conducted using procedures described by Shi et al (2011). PCR fragments were separated by gel electrophoresis with 1% agarose gel in 0.5 X TAE buffer and visualized under UV light using Dual UV transilluminator after staining with EcoDye TM DNA Staining Solution (Biofact Co., Daejeon, Korea).…”

“…For HRM analysis, the Sw5b-SNP primer pair and the SNP1 and SNP2 primer pairs reported in Shi et al (2011) (Table 2) were designed to amplify the DNA region carrying the target SNP. PCR was carried out in 20 μL reaction mixtures containing 10X h-Taq Reaction Buffer (25 mM MgCl 2 mix), 10 mM of each dNTP Mix, 10 pmol of each primer, 2.5 U/µL DNA polymerase, 20X EvaGreen TM (Solgent, Daejeon, Korea), 5X Band Doctor TM and 10ng of gDNA, using a CFX Connect TM Real-Time PCR Detection System (BIO-RAD, Hercules, USA).…”

“…In particular, for TSWV resistance conferred by the Sw-5b gene, diverse molecular markers such as RAPD (random amplified polymorphic DNA), RFLP, SCAR (sequence characterized amplified regions), CAPS, and INDEL markers have been reported (Dianese et al, 2010;Garland et al, 2005;Langella et al, 2004;Roselló et al, 2001;Śmiech et al, 2000;Stevens et al, 1995). Since the successful cloning of the Sw-5b gene, a gene-based marker and two SNPs specific to the Sw-5b allele for TSWV resistance have been reported (Shi et al, 2011). However, SNP analysis between resistant and susceptible alleles of the Sw-5b gene has not yet been intensively examined.…”