A modern ampelography: A genetic basis for leaf shape and venation patterning in grape

Authors: CHITWOOD, DANIEL - University Of California; RANJAN, AASHISH - University Of California; MARTINEZ, CIERA - University Of California; HEADLAND, LAUREN - University Of California; THIEM, THINH - University Of California; KUMAR, RAVI - University Of California; COVINGTON, MICHAEL - University Of California; HATCHER, TOMMY - University Of California; NAYLOR, DANIEL - University Of California; ZIMMERMAN, SHARON - University Of California; DOWNS, NORA - University Of California; RAYMUNDO, NATALY - University Of California; Buckler, Edward - Ed; MALOOF, JULIN - University Of California; Aradhya, Mallikarjuna; Prins, Bernard - Bernie; LI, LIN - Biostat Solutions, Inc; MYLES, SEAN - Nova Scotia Agricultural College; SINHA, NEELIMA - University Of California

Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/25/2013
Publication Date: 11/27/2013
Publication URL: http://www.plantphysiol.org/content/164/1/259.full.pdf+html
Citation: Chitwood, D.H., Ranjan, A., Martinez, C.C., Headland, L.R., Thiem, T., Kumar, R., Covington, M.F., Hatcher, T, Naylor, D.T., Zimmerman, S., Downs, N., Raymundo, N., Buckler IV, E.S., Maloof, J.N., Aradhya, M.K., Prins, B.H., Li, L., Myles, S., Sinha, N.R. 2013. A modern ampelography: A genetic basis for leaf shape and venation patterning in grape. Plant Physiology. 164(1):259-272.

Interpretive Summary: The growth of leaves are a key way plant species adapt to the environment each year, as they strive to collect light, compete with neighboring plants, avoid pathogens and insects, and allocate resources. Domesticated grape shows tremendous variation in leaf growth that has been studied for centuries. This study quantitatively evaluates leaf development and shape for the entire USDA germplasm of domesticated grape. It highlights that a substantial portion of the variation in leaf morphology is under strong genetic control, and that there are substantial opportunities to genetic map the controllers of this variation. Many hypotheses have been proposed about the adaptive nature of grape leaves for various environments, and this study shows that future genetic and breeding studies will be able to evaluate these hypotheses and put the most useful into application.

Technical Abstract: Terroir, the unique interaction between genotype, environment, and culture, is highly refined in domesticated grape (Vitis vinifera). Toward cultivating terroir, the science of ampelography tried to distinguish thousands of grape cultivars without the aid of genetics. This led to sophisticated phenotypic analyses of natural variation in grape leaves, which within a palmate-lobed framework exhibit diverse patterns of blade outgrowth, hirsuteness, and venation patterning. Here, we provide a morphometric analysis of more than 1,200 grape accessions. Elliptical Fourier descriptors provide a global analysis of leaf outlines and lobe positioning, while a Procrustes analysis quantitatively describes venation patterning. Correlation with previous ampelography suggests an important genetic component, which we confirm with estimates of heritability. We further use RNA-Seq of mutant varieties and perform a genome-wide association study to explore the genetic basis of leaf shape. Meta-analysis reveals a relationship between leaf morphology and hirsuteness, traits known to correlate with climate in the fossil record and extant species. Together, our data demonstrate a genetic basis for the intricate diversity present in grape leaves. We discuss the possibility of using grape leaves as a breeding target to preserve terroir in the face of anticipated climate change, a major problem facing viticulture.