Location: Plant Physiology and Genetics ResearchTitle: Phenotypic variations in leaf cuticular wax classes and constituents in a spring Camelina sativa diversity panel
Submitted to: Industrial Crops and Products
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/27/2017
Publication Date: 12/14/2017
Citation: Tomasi, P., Dyer, J.M., Jenks, M.A., Abdel-Haleem, H.A. 2017. Phenotypic variations in leaf cuticular wax classes and constituents in a spring Camelina sativa diversity panel. Industrial Crops and Products. 112:247-251.
Interpretive Summary: Camelina is a promising biofuel crop for marginal, semi-arid and arid regions, but it is necessary to develop new cultivars that can grow under water-limited conditions and still maintain comparably high yield and stability. Increasing the accumulation of leaf cuticular wax in Camelina could be one of the strategies to reduce nonstomatal water loss and thus resist abiotic stresses. Our analysis showed a wide range of phenotypic variation in leaf total wax, wax classes and constituents in a Camelina sativa diversity panel collected from different geographical regions. The detection of wide variations in leaf wax traits is the first step to understand wax biosynthetic pathways in Camelina, dissect its genetic network elements, identify candidate genes controlling these traits, and develop molecular markers for molecular breeding and genomic selection programs to increase drought resistance in Camelina. Our results indicated that among the wax constituents detected, primary alcohol homologues were dominant in all Camelina accessions, and were highly heritable traits. Secondly were the alkanes, which were also highly heritable in nature. Abundance of these wax constituents identifies them as good biomarkers for selection and breeding for drought resistance in Camelina through modifying cuticle composition and properties. High heritability values of these constituents suggest the feasibility of selecting for these traits during early generations of molecular breeding programs.
Technical Abstract: Among oilseed species, Camelina has received considerable attention as an oilseed crop that can be manipulated easily to meet important non-food bioenergy requirements, where it is relatively high in oil content and polyunsaturated fatty acids, and has a very short growing season with fairly good adaption to marginal lands and low input agricultural systems. To expand Camelina cultivation zones into more arid regions, it is important to develop new drought resistant cultivars that can grow under water-limited conditions. Increasing accumulated leaf cuticular wax in Camelina could be one of the strategies to reduce nonstomatal water loss and thus increase crop tolerance to drought. To extend our understanding of phenotypic variations in cuticular wax content and composition in Camelina sativa, we extracted and analyzed leaf wax constituents from a spring Camelina diversity panel containing 163 accessions. The diversity panel exhibited a wide range in total leaf wax contents, wax classes and constituents. Among primary alcohols, the dominant constituents were the C24, C26 and C28 homologues, while the C31 homologue was the most abundant alkane among all Camelina accessions. High heritability values of the primary alcohol class and its dominant constituent C24, C26 and C28 homologues, as well as the alkane class and abundant C29, C31, and C33 constituents, suggest the feasibility for selection of these traits during early generations of Camelina breeding programs. Positive correlation among leaf wax content, wax classes and their constituents suggests that modifying specific wax constituents could increase the wax loads, which in turn could enhance cuticle composition and properties. Quantitation of leaf wax traits in the Camelina diversity panel will underpin future analysis of the Camelina wax biosynthetic pathways, help dissect its genetic regulatory elements, identify candidate genes controlling these traits, and enable the development of molecular markers for molecular breeding programs aimed at increasing drought tolerance of Camelina.