Biology subjects

Ebeler, S. E.

Publications and source records attributed to Ebeler, S. E..

3 recordsLinked to original sources

bioRxiv2026

Allelic variation at a terpene synthase locus shapes wine monoterpene composition and aroma

The genetic basis of wine monoterpene variation and its sensory consequences remain poorly understood. We investigated how allelic variation at a chromosome 10 linalool QTL harboring a terpene synthase cluster, including VviTPS54, influences wine aroma in a Riesling x Cabernet Sauvignon mapping population. Twenty-six wines from progeny selected for contrasting genotypes were subjected to HS-SPME-GC-MS profiling and descriptive sensory analysis. Genotypes carrying the high-linalool Riesling allele produced substantially elevated monoterpene levels dominated by (3S)-linalool. Berry and wine monoterpene profiles were significantly correlated, and berry monoterpene glycosides showed broad correlations with wine monoterpenes. High-monoterpene genotypes were more closely associated with Floral, Tropical Fruit, and Apricot/Peach attributes, though perception was modulated by matrix effects from berry pigmentation. These results demonstrate that allelic variation at a terpene synthase locus drives coordinated changes in wine monoterpene composition and linked sensory attributes, while underscoring the complexity of translating genetic variation into sensory outcomes.

genetics↗

bioRxiv2026

Haplotype-specific expression of a terpene synthase underlies linalool variation in the grapevine cultivar Riesling

Grapevine cultivars vary widely in monoterpenoid content, yet the genetic and regulatory mechanisms underlying this variation remain poorly characterized beyond highly aromatic Muscat types. We profiled free volatiles and monoterpenoid glycosides in a Riesling x Cabernet Sauvignon F1 mapping population, revealing extensive variation and transgressive segregation consistent with multigenic control. QTL mapping identified 59 significant loci associated with 47 volatile compounds and monoterpene glycosides, including two major QTLs explaining 33.8% and 32.4% of phenotypic variance in (3S)-linalool accumulation. Integration of haplotype-resolved transcriptomics with metabolite data, enabled by a chromosome-scale diploid Riesling genome assembly, resolved a (3S)-linalool/nerolidol synthase cluster on chromosome 10 and identified VviTPS54 as the strongest candidate underlying linalool variation. VviTPS54 exhibited haplotype-specific expression strongly correlated with (3S)-linalool accumulation across genotypes, while no QTL was detected at the VviDXS1 locus and VviDXS1 expression was not correlated with terpene levels, indicating that regulatory variation within terpene synthase clusters, rather than methylerythritol phosphate (MEP) pathway flux, drives monoterpenoid composition in this population. These results establish regulatory variation of terpene synthases as a key mechanism underlying monoterpenoid diversity in grapevine and demonstrate that resolving such variation requires haplotype-phased genome assemblies coupled with haplotype-resolved transcriptomics to detect allele-specific expression differences at complex, heterozygous loci.

plant biology↗

bioRxiv2021

Rootstocks influence the response of ripening grape berries to leafroll associated viruses

Grapevine leafroll-associated virus (GLRaV) infections are accompanied by symptoms with varying severity. Using a dedicated experimental vineyard, we studied the responses to GLRaVs in ripening berries from Cabernet franc grapevines grafted to different rootstocks and with zero, one, or pairs of leafroll infection(s). RNA sequencing data were mapped to a high-quality Cabernet franc genome reference assembled to carry out this study and integrated with hormone and metabolite abundance data. This study identified several molecular levers that participate in responses to GLRaVs, including those that are condition-dependent. This included describing common responses to GLRaVs that were reproduced in two consecutive years, in plants grafted to different rootstocks, and in more than one infection condition. Though different infections were inconsistently distinguishable from one another overall, the effects of infections in plants grafted to different rootstocks were distinct at each developmental stage. Conserved responses included the modulation of pathogen detecting genes, increases in abscisic acid signaling and cytoskeleton remodeling gene expression. The abundance of abscisic acid (ABA), related metabolites, ABA and hormone signaling-related gene expression, and the expression of several transcription factor families differentiated rootstocks overall. These data show that rootstock influences the effect of GLRaVs in ripening berries.

plant biology↗