Characterization of Anatomical and Physiological Effects of Variegation Mutation on Grapevine

Abstract

Variegation is a common trait in plants that characteristically displays white or off-colored plant tissue. In grapevine, leaf variegation is expressed as white and pale green leaf tissue resulting in plants that are stunted in growth and hindered in development. In this study, several experiments were performed to investigate the impact of this mutation has on the anatomy of grape leaves and physiology of the plant. Histological staining of variegated and nonvariegated leaf tissue transections showed alterations to the leaf palisade mesophyll structure that affected leaf tissue width. An assay quantifying leaf pigments was performed to compare chlorophyll and carotenoid concentrations in leaves between variegated and wild-type seedlings, which showed that variegated leaf samples had reduced chlorophyll and carotenoid concentration. Through fluorescence imaging, we determined that photochemical efficiency of photosystem II (PSII) is reduced in variegated seedlings. By growing variegated and wild-type plants under high, medium, and low light intensities that variegated plants exposed to higher light intensity reduces the phenotypic expression of the variegation trait. Also, we found variegated plants to have significant reductions in growth traits such as plant height, leaf number, branch number, and dry weight compared with wild-type phenotype plants. Overall, our experiments revealed the variegation mutation altered normal leaf development causing significant effects to grapevine physiology.

Genetic Analyses for Leaf Variegation in Hybrid Grape Populations (Vitis spp.) Reveals Two Loci, Lvar1 and Lvar2

“…1F). In general, the variegation trait was highly expressed in the first few mature leaves and becomes less pronounced further in development (Olson and Clark 2021). Some variegated plants showed strong expression in all leaves throughout development.…”

“…Identifying the locus or loci controlling variegation would be especially useful for identifying parents that may be sources, and heterozygous carriers, of the trait to make more informative decisions in designing crosses. Because of the presence of variegation in the breeding program, understanding its association with other traits (in the heterozygous state), and its impact on plant growth and pleiotropic effects are important (Olson and Clark 2021).…”

Meiotic behavior of two grapevine somatic mutants with ornamental potential

“…Studies carried out in spontaneous or induced variegated grapevine mutants are mainly characterized by the description of the morphological and anatomical characteristics of the mutant plants (Antcliff and Webster, 1962;Sharma and Mukherjee, 1973). However, few of these studies were carried out to understand the genetic basis of the variegation (Reisch and Watson, 1984;Filler et al, 1994, Olson et al, 2021. Even though this information contributed to a better characterization of variegated grapevines, the regularity of the meiotic process or the percentage of pollen fertility were not investigated to evaluate if the mutation producing the variegated trait could have or not affected the meiosis or pollen fertility.…”

Mutation mapping of a variegated EMS tomato reveals an FtsH-like protein precursor potentially causing patches of four phenotype classes in the leaves with distinctive internal morphology

“…In principle, the main stage of the plastid differentiation stage is thylakoid formation which, if it fails to form a thylakoid membrane, leads to failure of the chloroplast conformation [ 13 , 14 , 33 , 68 ]. Plastids in leaf cells that fail to produce thylakoid structure during leaf development typically result in variegated patterns [ 13 , 68 , 69 ].…”