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Article|28 Feb 2022|OPEN
Stable QTL for malate levels in ripe fruit and their transferability across Vitis species
Noam Reshef1 , , Avinash Karn2 , David C. Manns3 , Anna Katharine Mansfield3 , Lance Cadle-Davidson4 , Bruce Reisch2 and Gavin L. Sacks,1
1Department of Food Science, Cornell University, Ithaca, NY 14853, USA
2Horticulture Section, School of Integrative Plant Science, Cornell University, Geneva, NY 14456, USA
3Department of Food Science, Cornell AgriTech, Geneva, NY 14456, USA
4USDA-ARS, Grape Genetics Research Unit, Geneva, NY 14456, USA
*Corresponding author. E-mail: nr444@cornell.edu

Horticulture Research 9,
Article number: uhac009 (2022)
doi: https://doi.org/10.1093/hr/uhac009
Views: 175

Received: 09 Jul 2021
Accepted: 21 Oct 2021
Published online: 28 Feb 2022

Abstract

Malate is a major contributor to the sourness of grape berries (Vitis spp.) and their products, such as wine. Excessive malate at maturity, commonly observed in wild Vitis grapes, is detrimental to grape and wine quality and complicates the introgression of valuable disease resistance and cold hardy genes through breeding. This study investigated an interspecific Vitis family that exhibited strong and stable variation in malate at ripeness for five years and tested the separate contribution of accumulation, degradation, and dilution to malate concentration in ripe fruit in the last year of study. Genotyping was performed using transferable rhAmpSeq haplotype markers, based on the Vitis collinear core genome. Three significant QTL for ripe fruit malate on chromosomes 1, 7, and 17, accounted for over two-fold and 6.9 g/L differences, and explained 40.6% of the phenotypic variation. QTL on chromosomes 7 and 17 were stable in all and in three out of five years, respectively. Variation in pre-veraison malate was the major contributor to variation in ripe fruit malate (39%), and based on two and five years of data, respectively, their associated QTL overlapped on chromosome 7, indicating a common genetic basis. However, use of transferable markers on a closely related Vitis family did not yield a common QTL across families. This suggests that diverse physiological mechanisms regulate the levels of this key metabolite in the Vitis genus, a conclusion supported by a review of over a dozen publications from the past decade, showing malate-associated genetic loci on all 19 chromosomes.