Proteome and Acetyl-Proteome Profiling of Camellia sinensis cv. 'Anjin Baicha' during Periodic Albinism Reveals Alterations in Photosynthetic and Secondary Metabolite Biosynthetic Pathways.

Yan-Xia Xu,Lian-Qi Zhou,Si-Yan Shen,Wei Chen,Chun-Lei Ma,Liang Chen,Yan-Yan Zhou

doi:10.3389/fpls.2017.02104

Abstract

Tea leaf color is not only important from an aesthetics standpoint but is also related to tea quality. To investigate the molecular mechanisms that determine tea leaf color, we examined Camellia sinensis cv. ‘Anji Baicha’ (an albino tea cultivar) by tandem mass tag isobaric labeling to generate a high-resolution proteome and acetyl-proteome atlas of three leaf developmental stages. We identified a total of 7,637 proteins and quantified 6,256; of these, 3,232 were classified as differentially accumulated proteins (DAPs). We also identified 3,161 lysine acetylation sites in 1,752 proteins and quantified 2,869 in 1,612 proteins. The acetylation levels at 468 sites were significantly altered across the three developmental stages during periodic albinism; the corresponding proteins were associated with a variety of biological processes. Interestingly, a large number of DAPs and acetylated proteins with increased/decreased acetylation were related to photosynthesis and secondary metabolite biosynthetic pathways, suggesting that the accumulation or acetylation level of these proteins regulates periodic albinism in ‘Anji Baicha.’ Additionally, overlap between succinylome and acetylome among three ‘Anji Baicha’ developmental stages were found. These data provide important insight into the mechanisms of leaf coloration in the tea plant. The mass spectrometry data have been deposited to Proteome X change via the PRIDE partner repository with the data set identifier PXD008134.

Highlights

The tea plant [Camellia sinensis (L.) O
Taking into account the change in pigmentation and secondary metabolite levels during periodic albinism in ‘Anji Baicha’ (Figure 2) and the results of the Kyoto Encyclopedia of Genes Genomes (KEGG) pathway analysis (Figure S3E), we examined the accumulation levels of proteins involved in photosynthesis and biosynthesis of mostly secondary metabolites in tea plant (Figures 3, 4 and Tables S2, S3)
We identified several proteins associated with theanine/flavonoid biosynthesis that were differentially accumulated during periodic albinism in ‘Anji Baicha’ (Figure 4 and Table S3), including four in the theanine biosynthesis pathway—i.e., glutamine synthetase (GS), glutamate synthase (GLS), glutamate dehydrogenase (GDH), and alanine transaminase (ALT)

Summary

Introduction

The tea plant [Camellia sinensis (L.) O. The quality of ‘Anji Baicha’ is higher when new shoots become albino due to their high amino acid and modest tea polyphenol contents. In Streptomyces roseosporus and Bacillus amyloliquefaciens, 1,143 and 3,268 lysine ASs were identified on 667 and 1,254 APs, respectively (Liao et al, 2014; Mo et al, 2015; Liu et al, 2016). We identified 3,161 lysine ASs on 1,752 APs, which is more than what has been previously reported in plants. The grape data were from the fruit; Arabidopsis data were from young seedling or mature leaves or isolated mitochondria; soybean and pea data were from immature seeds and purified mitochondria, respectively; and data from strawberry as well as those from the tea plant in our study were from the leaves. Our findings represent the first lysine acetylome map of tea plants

Methods

Results

Discussion

Conclusion