Transcriptomic analysis reveals mechanism of light-sensitive albinism in tea plant Camellia sinensis ‘Huangjinju’

Abstract

Background Camellia sinensis ‘Huangjinju’ is an albino tea variety developed recently in China. Young leaves of ‘Huangjinju’ demonstrate bright yellow when cultivated under natural sunlight, but regreens under reduced light intensity. To elucidate the physiological and molecular mechanisms of this light-sensitive albinism, we compared leaf pigmentation, metabolites, cellular ultrastructure and transcriptome between plants cultured under natural sunlight and shade. Results Shading treatment doubled the chlorophyll concentration and regreened albino leaves; carotenoid also increased by 30%. Electron microscopy analyses showed that chloroplast not only increased in number but also in size with a complete set of components. In addition, regreened leaves also had a significantly higher concentration of polyphenols and catechins than albino leaves. At transcriptomic level, a total of 507 genes were differentially expressed in response to light condition changes. The most enriched pathways include light harvest protein complex, response to stimuli, oxidation-reduction process, generation of precursor metabolites and energy response. Conclusion The integrated strategy in this study allows a mechanistic understanding of leaf albinism in light-sensitive tea plants and suggested the regulation of gene networks involved in pigmentation and protein processing. Results from this study provide valuable information to this area and can benefit the domestication and artificial breeding to develop new albino tea varieties.

Screening the Key Region of Sunlight Regulating the Flavonoid Profiles of Young Shoots in Tea Plants (Camellia sinensis L.) Based on a Field Experiment

“…It was reported that shade treatment promoted the accumulation of catechin compounds in the young shoots of the light-sensitive tea cultivar ‘Huangjinya’ [ 36 ]. A similar phenomenon was also observed in the greening tea leaves of the albino cultivar ‘Huangjinju’ under shade treatment, which had higher contents of catechins than the albino tea leaves [ 37 ]. Differing from regular tea cultivars, the enhanced biosynthesis of flavonoids in the shade-grown albino tea leaves was attributed to the differential biosynthetic mechanism of the flavonoids [ 35 ].…”

Response to the Cold Stress Signaling of the Tea Plant (Camellia sinensis) Elicited by Chitosan Oligosaccharide

“…In the present study, PsbR was up-regulated, which was consistent with the action of chitosan heptamer response in wheat seedling [49]. Besides, Chlorophyll a/b-binding protein can participate in light uptake, transfer energy to the reaction centers of the photosystem I and photosystem II, and regulate the excitation energy distribution to maintain the structure of the thylakoid membrane [50], and all of 23 chlorophyll a/b-binding protein genes were also up-regulated, which can imply the recovery of photosynthesis activities by COS treatment under cold stress [51]. These results indicate that COS may enhance photosynthesis via the upregulation of related proteins to improve the cold resistance of tea plant.…”

Enhancement of Photosynthetic Capacity in Spongy Mesophyll Cells in White Leaves of Actinidia kolomikta

“… Wang et al (2020) reported that light-harvesting chlorophyll a/b-binding protein (LHC) was closely linked to aberrant chloroplast development in yellow-leaf tea plants. Under the shade, upregulation of chlorophyll a/b-binding protein genes in yellow leaves played an important role in the recovery of photosynthesis activities ( Jiang et al, 2020 ). Furthermore, some genes regulated RuBisCO activity also involved in carbon assimilation, for example, Chloroplast Nucleoids DNA-binding Protease ( CND41 ) and RuBisCO activase ( RCA ).…”