Proteomic Analysis Reveals the Leaf Color Regulation Mechanism in Chimera Hosta “Gold Standard” Leaves

Abstract

Leaf color change of variegated leaves from chimera species is regulated by fine-tuned molecular mechanisms. Hosta "Gold Standard" is a typical chimera Hosta species with golden-green variegated leaves, which is an ideal material to investigate the molecular mechanisms of leaf variegation. In this study, the margin and center regions of young and mature leaves from Hosta "Gold Standard", as well as the leaves from plants after excess nitrogen fertilization were studied using physiological and comparative proteomic approaches. We identified 31 differentially expressed proteins in various regions and development stages of variegated leaves. Some of them may be related to the leaf color regulation in Hosta "Gold Standard". For example, cytosolic glutamine synthetase (GS1), heat shock protein 70 (Hsp70), and chloroplastic elongation factor G (cpEF-G) were involved in pigment-related nitrogen synthesis as well as protein synthesis and processing. By integrating the proteomics data with physiological results, we revealed the metabolic patterns of nitrogen metabolism, photosynthesis, energy supply, as well as chloroplast protein synthesis, import and processing in various leaf regions at different development stages. Additionally, chloroplast-localized proteoforms involved in nitrogen metabolism, photosynthesis and protein processing implied that post-translational modifications were crucial for leaf color regulation. These results provide new clues toward understanding the mechanisms of leaf color regulation in variegated leaves.

Comparative Proteomic Analysis by iTRAQ Reveals that Plastid Pigment Metabolism Contributes to Leaf Color Changes in Tobacco (Nicotiana tabacum) during Curing

“…Chlorophyll was found to be the most abundant plastid pigment in tobacco leaves at 0 h, but the ratio of carotenoid/chlorophyll of different samples was all larger than or equal to 1.30 during 48-72 h. In addition, the ratios between xanthophylls and β-carotene of different samples were all larger than or equal to 1.71 during 0-72 h. Thus, the tobacco leaves showed a green phenotype at 0 h and a yellow phenotype at 48 h and 72 h. Pigment metabolism and their relative contents were responsible for the formation of the yellow phenotype, which was consistent with previous reports [11,30,39]. The data were expressed as the color values of lightness L*, greenness a*, and yellowness b* [2,11,27]. In this study, the change in color was quantified as the increment in the values of L*, a*, and b*, which is associated with the pigment degradation and the increase in the relative concentrations of the carotenoid and the phenotypic change in tobacco leaves during curing.…”

“…Proteomics analysis provides a broad perspective on the process of leaf color change, which prompts us not only to pay attention to the pigment metabolism pathway but also to further screen some key proteins related to the pigment metabolism and color change in tobacco leaves during curing [27][28][29]. Quantitative proteome analysis revealed that hundreds of DEPs were identified in all leaf samples during curing.…”

“…The color change is determined by a dynamic shift in pigment composition and their contents in plants, which is associated with the regulation of differentially expressed proteins (DEPs). Proteins involved in photosynthesis, glyoxylate metabolism, carbon and nitrogen metabolism, anthocyanin biosynthesis, protein processing, and redox homeostasis are crucial for color regulation in plants [8,[27][28][29]. Moreover, leaf color change is a complex programmed process that is closely related to pigment metabolism and is regulated by fine-tuned molecular mechanisms [8,27,30].…”

Comparative Proteomic and Physiological Analysis Reveals the Variation Mechanisms of Leaf Coloration and Carbon Fixation in a Xantha Mutant of Ginkgo biloba L.

“…These proteins function directly in the electron transport and carbon fixation pathways (Figure 6, Table 1). Several studies have reported that some photosystem proteins in xantha mutants are deficient or present at low levels [40,41]. However, we observed that three different protein species, Rieske iron–sulphur protein precursor (PetC, spot 3024), oxygen-evolving enhancer protein 2 (OEC, spot 1052), and ferredoxin NADP reductase (FNR, spot 6151 and spot 6152), which originate from the cytochrome b6f complex PSII and PSI, respectively, were increased in YL (Figure 6).…”

Cytologic, Genetic, and Proteomic Analysis of a Yellow Leaf Mutant of Sesame (Sesamum indicumL.),Siyl-1

“…This method has been currently used in the study of environment stress on plants, regulation mechanism of leaf color, etc. [21–23]. Till date, there is no study reporting the use of proteomics in understanding sesame leaves color, but this method is a powerful approach to identify and isolate different proteins.…”