Proteomic analysis of young leaves at three developmental stages in an albino tea cultivar

Abstract

BackgroundWhite leaf No.1 is a typical albino tea cultivar grown in China and it has received increased attention in recent years due to the fact that white leaves containing a high level of amino acids, which are very important components affecting the quality of tea drink. According to the color of its leaves, the development of this tea cultivar is divided into three stages: the pre-albinistic stage, the albinistic stage and the regreening stage. To understand the intricate mechanism of periodic albinism, a comparative proteomic approach based on two-dimensional electrophoresis (2-DE) and mass spectrometry was adopted first time to identify proteins that changed in abundance during the three developmental periods.ResultsThe 2-DE results showed that the expression level of 61 protein spots varied markedly during the three developmental stages. To analyze the functions of the significantly differentially expressed protein spots, 30 spots were excised from gels and analyzed by matrix-assisted laser desorption ionization-time of flight-tandem mass spectrometry. Of these, 26 spots were successfully identified. All identified protein spots were involved in metabolism of carbon, nitrogen and sulfur, photosynthesis, protein processing, stress defense and RNA processing, indicating these physiological processes may play crucial roles in the periodic albinism. Quantitative real-time RT-PCR analysis was used to assess the transcriptional level of differentially expressed proteins. In addition, the ultrastructural studies revealed that the etioplast-chloroplast transition in the leaf cell of White leaf No. 1 was inhibited and the grana in the chloroplast was destroyed at the albinistic stage.ConclusionsIn this work, the proteomic analysis revealed that some proteins may have important roles in the molecular events involved in periodic albinism of White leaf No. 1 and identificated many attractive candidates for further investigation. In addition, the ultrastructural studies revealed that the change in leaf color of White leaf No. 1 might be a consequence of suppression of the etioplast-chloroplast transition and damage to grana in the chloroplast induced by temperature. These results provide much useful information to improve our understanding of the mechanism of albinism in the albino tea cultivar.

Global Transcriptional Analysis Reveals the Complex Relationship between Tea Quality, Leaf Senescence and the Responses to Cold-Drought Combined Stress in Camellia sinensis

“…This compound was known to impose tea infusion a unique umami taste (Yamaguchi and Ninomiya, 2000). Theanine biosynthesis in tea plants had shown to be influenced by drought and cold stress (Li et al, 2011; Wang et al, 2016). By activating the theanine synthesis pathway, the excess ammonium can be stored in theanine and tea plants can avoid damage from the high concentration of ammonium under abiotic stress (Li et al, 2011).…”

“…Theanine biosynthesis in tea plants had shown to be influenced by drought and cold stress (Li et al, 2011; Wang et al, 2016). By activating the theanine synthesis pathway, the excess ammonium can be stored in theanine and tea plants can avoid damage from the high concentration of ammonium under abiotic stress (Li et al, 2011). Drought or drought-induced leaf senescence may facilitate the theanine biosynthesis in tea plants via up-regulating ADC and GOGAT to promote the accumulation of substrate ethylamine and glutamate, respectively.…”

Metabolic Flux Redirection and Transcriptomic Reprogramming in the Albino Tea Cultivar ‘Yu-Jin-Xiang’ with an Emphasis on Catechin Production

“…A group of albino Camellia sinensis cultivars, such as ‘Yu-Jin-Xiang’ (‘YJX’) and ‘Zhonghuang 2′, produce pale or yellow young leaves in early spring and turn green at later growing stages1234. These cultivars are highly desired by the tea industry because young pale (virescent) tea leaves can be used to produce a high quality green tea with an enhanced savory (“umami”) taste and reduced stringency, while mature green leaves can maintain plant growth and regular productivity in successive years.…”

“…These cultivars are highly desired by the tea industry because young pale (virescent) tea leaves can be used to produce a high quality green tea with an enhanced savory (“umami”) taste and reduced stringency, while mature green leaves can maintain plant growth and regular productivity in successive years. Compared with the mature leaves of an albino cultivar and those of common green cultivars, young albino or yellow leaves usually contain enhanced levels of the non-protein amino acid theanine and reduced levels of catechins, a group of flavan-3-ols found in tea at high levels124. These metabolites are crucial tea flavor determinants.…”

Effect of Seasons on Theanine Levels in Different Kenyan Commercially Released Tea Cultivars and Its Variation in Different Parts of the Tea Shoot

“…There is no much documented work that has been done on these cultivars seasonally. Theanine level variation in cultivars could also be due to enzymes responsible for theanine synthesis: glutamine synthetase, glutamine synthase, glutamate dehydrogenase, alanine transaminase alanine decarboxylase and theanine hydrolase which could be differentially expressed in different clones [28].…”