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McCallum J, Laing W, Bulley S, Thomson S, Catanach A, Shaw M, Knaebel M, Tahir J, Deroles S, Timmerman-Vaughan G, Crowhurst R, Hilario E, Chisnall M, Lee R, Macknight R, Seal A. Molecular Characterisation of a Supergene Conditioning Super-High Vitamin C in Kiwifruit Hybrids. Plants (Basel) 2019; 8:E237. [PMID: 31336644 PMCID: PMC6681377 DOI: 10.3390/plants8070237] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 07/15/2019] [Accepted: 07/16/2019] [Indexed: 12/20/2022]
Abstract
During analysis of kiwifruit derived from hybrids between the high vitamin C (ascorbic acid; AsA) species Actinidia eriantha and A. chinensis, we observed bimodal segregation of fruit AsA concentration suggesting major gene segregation. To test this hypothesis, we performed whole-genome sequencing on pools of hybrid genotypes with either high or low AsA fruit. Pool-GWAS (genome-wide association study) revealed a single Quantitative Trait Locus (QTL) spanning more than 5 Mbp on chromosome 26, which we denote as qAsA26.1. A co-dominant PCR marker was used to validate this association in four diploid (A. chinensis × A. eriantha) × A. chinensis backcross families, showing that the A. eriantha allele at this locus increases fruit AsA levels by 250 mg/100 g fresh weight. Inspection of genome composition and recombination in other A. chinensis genetic maps confirmed that the qAsA26.1 region bears hallmarks of suppressed recombination. The molecular fingerprint of this locus was examined in leaves of backcross validation families by RNA sequencing (RNASEQ). This confirmed strong allelic expression bias across this region as well as differential expression of transcripts on other chromosomes. This evidence suggests that the region harbouring qAsA26.1 constitutes a supergene, which may condition multiple pleiotropic effects on metabolism.
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Affiliation(s)
- John McCallum
- New Cultivar Innovation, The New Zealand Institute for Plant & Food Research Limited, Private Bag 4704, Christchurch 8140, New Zealand.
- Biochemistry Department, University of Otago, Dunedin 9054, New Zealand.
| | - William Laing
- New Cultivar Innovation, The New Zealand Institute for Plant & Food Research Limited, Private Bag 11600, Palmerston North 4442, New Zealand
| | - Sean Bulley
- New Cultivar Innovation, The New Zealand Institute for Plant & Food Research Limited, Private Bag 11600, Palmerston North 4442, New Zealand
| | - Susan Thomson
- New Cultivar Innovation, The New Zealand Institute for Plant & Food Research Limited, Private Bag 4704, Christchurch 8140, New Zealand
| | - Andrew Catanach
- New Cultivar Innovation, The New Zealand Institute for Plant & Food Research Limited, Private Bag 4704, Christchurch 8140, New Zealand
| | - Martin Shaw
- New Cultivar Innovation, The New Zealand Institute for Plant & Food Research Limited, Private Bag 4704, Christchurch 8140, New Zealand
| | - Mareike Knaebel
- New Cultivar Innovation, The New Zealand Institute for Plant & Food Research Limited, Private Bag 11600, Palmerston North 4442, New Zealand
| | - Jibran Tahir
- New Cultivar Innovation, The New Zealand Institute for Plant & Food Research Limited, Private Bag 11600, Palmerston North 4442, New Zealand
| | - Simon Deroles
- New Cultivar Innovation, The New Zealand Institute for Plant & Food Research Limited, Private Bag 11600, Palmerston North 4442, New Zealand
| | - Gail Timmerman-Vaughan
- New Cultivar Innovation, The New Zealand Institute for Plant & Food Research Limited, Private Bag 4704, Christchurch 8140, New Zealand
| | - Ross Crowhurst
- New Cultivar Innovation, The New Zealand Institute for Plant & Food Research Limited, Private Bag 92169, Auckland Mail Centre, Auckland 1142, New Zealand
| | - Elena Hilario
- New Cultivar Innovation, The New Zealand Institute for Plant & Food Research Limited, Private Bag 92169, Auckland Mail Centre, Auckland 1142, New Zealand
| | - Matthew Chisnall
- Biochemistry Department, University of Otago, Dunedin 9054, New Zealand
| | - Robyn Lee
- Biochemistry Department, University of Otago, Dunedin 9054, New Zealand
| | - Richard Macknight
- Biochemistry Department, University of Otago, Dunedin 9054, New Zealand
| | - Alan Seal
- New Cultivar Innovation, The New Zealand Institute for Plant & Food Research Limited, 412 No 1 Road, RD 2 Te Puke 3182, New Zealand
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