Malate Content in Wild Vitis spp. Demonstrates a Range of Behaviors during Berry Maturation

Abstract

Wild <i>Vitis</i> spp. and their interspecific hybrids are known to have high malate concentrations at sugar maturity as compared to domesticated <i>Vitis vinifera</i>, but it is unknown if differences in malate at harvest among species arise from differences in malate accumulation or degradation. Over two years, fruit from <i>Vitis riparia</i> and <i>Vitis cinerea</i> accessions along with commercial <i>V. vinifera</i> and interspecific hybrid cultivars were collected at multiple time points. In contrast to the well-known biphasic behavior of malate in <i>V. vinifera</i> (preveraison accumulation, postveraison degradation), we observed a range of behaviors for malate in wild species. On average, <i>V. riparia</i> accessions had malate per berry comparable to <i>V. vinifera</i> just prior to veraison, but degraded malate to a much lesser extent. <i>V. cinerea</i> accessions had lower malate prior to veraison than other species but showed an increase in malate from pre- to postveraison. Variation in postveraison malate behavior appears related to diminished malate degradation in the mesocarp of wild <i>Vitis</i> spp. Our results indicate that studies of malate behavior in <i>Vitis</i> spp. and their hybrids should include both pre- and postveraison time points.