Developmental and Genotypic Variation in Leaf Wax Content and Composition, and in Expression of Wax Biosynthetic Genes in Brassica oleracea var. capitata

Abstract

Cuticular waxes act as a protective barrier against environmental stresses. In the present study, we investigated developmental and genotypic variation in wax formation of cabbage lines, with a view to understand the related morphology, genetics and biochemistry. Our studies revealed that the relative expression levels of wax biosynthetic genes in the first-formed leaf of the highest-wax line remained constantly higher but were decreased in other genotypes with leaf aging. Similarly, the expression of most of the tested genes exhibited decrease from the inner leaves to the outer leaves of 5-month-old cabbage heads in the low-wax lines in contrast to the highest-wax line. In 10-week-old plants, expression of wax biosynthetic genes followed a quadratic function and was generally increased in the early developing leaves but substantially decreased at the older leaves. The waxy compounds in all cabbage lines were predominately C29-alkane, -secondary alcohol, and -ketone. Its deposition was increased with leaf age in 5-month-old plants. The high-wax lines had dense, prominent and larger crystals on the leaf surface compared to low-wax lines under scanning electron microscopy. Principal component analysis revealed that the higher expression of LTP2 genes in the lowest-wax line and the higher expression of CER3 gene in the highest-wax line were probably associated with the comparatively lower and higher wax content in those two lines, respectively. This study furthers our understanding of the relationships between the expression of wax biosynthetic genes and the wax deposition in cabbage lines.Highlight: In cabbage, expression of wax-biosynthetic genes was generally decreased in older and senescing leaves, while wax deposition was increased with leaf aging, and C29-hydrocarbon was predominant in the wax crystals.

Fine Mapping and Candidate Gene Identification for Wax Biosynthesis Locus, BoWax1 in Brassica oleracea L. var. capitata

“…Wax composition and content can vary according to species, ontogeny, and environment ( Jenks and Ashworth, 1999 ; Laila et al, 2016 ). As noted previously, the major components of wax are VLCFAs and their derivatives, including alkanes, aldehydes, primary and secondary alcohols, ketones, and esters ( Riederer and Müller, 2006 ; Bernard and Joubès, 2013 ).…”

Physio-morphological traits and drought stress responses in three wild Mediterranean taxa of Brassicaceae

“…The tomentose leaf surface could also be a main factor contributing to lowering cuticular transpiration when water supply was low. Under drought stress, instead, B. macrocarpa maintained the lowest leaf temperatures, possibly explained by a combination of leaf reflection due to higher presence of waxes on the epidermis that reduces also cuticular water loss (Holmes and Keiller 2002;Laila et al 2017) and the higher water content, confirmed by higher RWC and less negative Ψ L.…”

The role ofLathyrus sativusflower surface wax in short-range attraction and stimulant for nymph laying by an adult viviparous aphid

“…But, nonadecane was predominant alkane in seed coat surface waxes of BIO L 212 Ratan and Nirmal B-1 (Adhikary et al ., 2014); whereas palmitoleic acid, and palmitic acid and lauric acid were the most abundant free fatty acids in seed coat surface waxes of BIO L 212 Ratan and Nirmal B-1, respectively (Adhikary et al ., 2016). The present study revealed that the composition of n -alkanes and free fatty acids in surface waxes of plants might vary between plant species as well as within different cultivars of a plant species including various parts of a plant species (Piasentier et al ., 2000; Dodoš et al ., 2015; Wang et al ., 2015; Laila et al ., 2017).…”