A Quantitative Genetic Basis for Leaf Morphology in a Set of Precisely Defined Tomato Introgression Lines

Abstract

Introgression lines (ILs), in which genetic material from wild tomato species is introgressed into a domesticated background, have been used extensively in tomato (Solanum lycopersicum) improvement. Here, we genotype an IL population derived from the wild desert tomato Solanum pennellii at ultrahigh density, providing the exact gene content harbored by each line. To take advantage of this information, we determine IL phenotypes for a suite of vegetative traits, ranging from leaf complexity, shape, and size to cellular traits, such as stomatal density and epidermal cell phenotypes. Elliptical Fourier descriptors on leaflet outlines provide a global analysis of highly heritable, intricate aspects of leaf morphology. We also demonstrate constraints between leaflet size and leaf complexity, pavement cell size, and stomatal density and show independent segregation of traits previously assumed to be genetically coregulated. Meta-analysis of previously measured traits in the ILs shows an unexpected relationship between leaf morphology and fruit sugar levels, which RNA-Seq data suggest may be attributable to genetically coregulated changes in fruit morphology or the impact of leaf shape on photosynthesis. Together, our results both improve upon the utility of an important genetic resource and attest to a complex, genetic basis for differences in leaf morphology between natural populations.

Quantitative Genetic Analysis Indicates Natural Selection on Leaf Phenotypes Across Wild Tomato Species (Solanumsect.Lycopersicon; Solanaceae)

“…esculentum (Slyc). Previous studies using this IL population have identified numerous QTL (Lippman et al 2007) for traits ranging from fruit metabolite concentrations (Schauer et al 2006), yield , reproductive isolation , and leaf traits (Holtan and Hake 2003;Chitwood et al 2013). With these data, we confirm evidence in support of adaptive evolution of leaf traits, examine the physiological and ecological significance of trait variation in several clearly adaptive traits, and identify potential molecular developmental mechanisms responsible for this trait variation.…”

A feedback insensitive isopropylmalate synthase affects acylsugar composition in cultivated and wild tomato

“…The introgressed segments appear as solid bars in which the boundary edge of each segment is indicated by inclusive (+) and exclusive (2) flanking markers. Numbers at the bottom denote the genomic positions according to a previous publication (Chitwood et al, 2013). D, ProSlIPMS3:GFP-GUS plants show GFP expression in the apical cells of type I/IV trichomes.…”

Multiscale quantification of morphodynamics: MorphoLeaf, software for 2-D shape analysis

“…Discretisation of shape based on evenly spaced marks along the contour and averaging these marks over many leaves allows the proper description and quantification of simple entire leaves (Langlade et al, 2005;Bensmihen et al, 2008;Weight et al, 2008;Feng et al, 2009). Likewise, landmark-independent Fourierbased analysis of the contour is useful to quantify the general shape of the leaf (Chitwood et al, 2012(Chitwood et al, , 2013(Chitwood et al, , 2014. However, because these approaches result in smooth, averaged contours, neither of them is appropriate to accurately capture characteristic structures with a variable position such as teeth or lobes (Chitwood et al, 2012(Chitwood et al, , 2013.…”