Environment-Driven Adaptations of Leaf Cuticular Waxes Are Inheritable for Medicago ruthenica

Abstract

Cuticular waxes covering the plant surface play pivotal roles in helping plants adapt to changing environments. However, it is still not clear whether the responses of plant cuticular waxes to their growing environments are inheritable. We collected seeds of Medicago ruthenica (a perennial legume) populations from 30 growing sites in northern China and examined the variations of leaf cuticular waxes in a common garden experiment. Four wax genes, MrFAR3-1, MrFAR3-2, MrCER1, and MrKCS1, involved in biosynthesis of predominant wax classes (primary alcohol and alkane) and wax precursors, were isolated to test the contributions of genetic variations of the coding sequences (CDS) and the promoter sequences and epigenetic modifications. The plasticity responses of the cuticular waxes were further validated by two stress-modeling experiments (drought and enhancing ultraviolet B). Great variations in total wax coverage and abundance of wax classes or wax compounds were observed among M. ruthenica populations in a common garden experiment. Stress-modeling experiments further validated that M. ruthenica would alter leaf wax depositions under changed growing conditions. The transcriptional levels of the wax genes were positively or negatively correlated with amounts of cuticular waxes. However, the analysis of promoter methylation showed that the methylation level of the promoter region was not associated with their expressions. Although both promoter sequences and CDS showed a number of polymorphic sites, the promoters were not naturally selected and insignificant difference could be observed in the numbers and types of acting elements of the four wax genes among populations. In contrast, the CDS of the wax genes were naturally selected, with a number of missense mutations resulting in alterations of the amino acid as well as their isoelectric points and polarities, which could impact on enzyme function/activity. We conclude that long-term adaptation under certain environments would induce genetic mutation of wax biosynthesis genes, resulting in inheritable alterations of cuticular wax depositions.

Cuticular Wax Variability of Abies alba, A.×borisii‐regis and A. cephalonica from the Balkans: Chemophenetic and Ecological Aspects

“…[20] Plants are able to adjust the load and composition of cuticular waxes in accordance with changing environment and abiotic stress conditions, such as temperature fluctuations, drought, radiation level etc. [22] In the recent decades, wax compounds have received growing attention from the standpoint of chemophenetics. Their chemophenetic significance in conifer order Pinales at the familial and subfamilial level has been addressed in detail by Maffei et al [23] Moreover, they are often used as markers in studies on population variability and differentiation of several conifer species.…”

Exploring Genetic Diversity in Romanian Lycium Species: A Comparative Study of Wild and Cultivated Genotypes

“…The current study marks the initial phase of a broader project focused on genes related to resistance to abiotic and biotic stress, focusing here on cuticle thickness. This aspect is critically important due to cuticle significant influence on resistance to drought, insolation, and pests [66][67][68], as the cuticle is essential for plant survival in periods of severe drought [69] and pests and disease attack [70]. BODYGUARD genes in plants typically encode for proteins that are directly involved in defending the plant against various stresses, including the biosynthesis of cutin in Arabidopsis [69,71,72], mainly the α/β hydrolase protein [69,71,73].…”

Temperature has a major effect on the cuticular wax composition of bilberry (Vaccinium myrtillus L.) fruit

“…Stress modeling in addition to field and controlled studies have revealed that plants adjust their cuticular wax load and composition to adapt to changing environment and abiotic stress conditions, such as drought, temperature fluctuations, and radiation level ( Shepherd and Griffiths, 2006 ; Guo et al, 2015 , 2021 ; Gao et al, 2016 ). Drought stress has been shown to increase cuticular wax load and the content of alkanes in Arabidopsis ( Kim et al, 2007 ; Kosma et al, 2009 ), while enhanced UV-B radiation was shown to increase the content of alkanes and primary alcohols in cucumber ( Cucumis sativus ) cotyledon ( Fukuda et al, 2008 ).…”