Repressed Gene Expression of Photosynthetic Antenna Proteins Associated with Yellow Leaf Variation as Revealed by Bulked Segregant RNA-seq in Tea Plant Camellia sinensis

Abstract

The young leaves and shoots of albino tea cultivars are usually characterized as having a yellow or pale color, high amino acid, and low catechin. Increasing attention has been paid to albino tea cultivars in recent years because their tea generally shows high umami and reduced astringency. However, the genetic mechanism of yellow-leaf variation in albino tea cultivar has not been elucidated clearly. In this study, bulked segregant RNA-seq (BSR-seq) was performed on bulked yellow- and green-leaf hybrid progenies from a leaf color variation population. A total of 359 and 1134 differentially expressed genes (DEGs) were identified in the yellow and green hybrid bulked groups (Yf vs Gf) and parent plants (Yp vs Gp), respectively. The significantly smaller number of DEGs in Yf versus Gf than in Yp versus Gp indicated that individual differences could be reduced within the same hybrid progeny. Analysis of Gene Ontology and Kyoto Encyclopedia of Genes and Genomes revealed that the photosynthetic antenna protein was most significantly enriched in either the bulked groups or their parents. Interaction was found among light-harvesting chlorophyll a/b -binding proteins (LHC), heat shock proteins (HSPs), and enzymes involved in cuticle formation. Combined with the transcriptomic expression profile, results showed that the repressed genes encoding LHC were closely linked to aberrant chloroplast development in yellow-leaf tea plants. Furthermore, the photoprotection and light stress response possessed by genes involved in HSP protein interaction and cuticle formation were discussed. The expression profile of DEGs was verified via quantitative real-time PCR analysis of the bulked samples and other F1 individuals. In summary, using BSR-seq on a hybrid population eliminated certain disturbing effects of genetic background and individual discrepancy, thereby helping this study to intensively focus on the key genes controlling leaf color variation in yellow-leaf tea plants.

Genome‐wide identification of the light‐harvesting chlorophyll a/b binding (Lhc) family in Gossypium hirsutum reveals the influence of GhLhcb2.3 on chlorophyll a synthesis

“…Studies of light harvesting in plants revealed that Lhc family proteins are involved in regulation and distribution of excitation energy between PSI and PSII, in photoprotection as well as in response to various stresses (Singh et al ., 2014; Fristedt et al ., 2015; Gao et al ., 2018). Research on Lhc family proteins in algae, Arabidopsis thaliana and tea, revealed that these proteins play a vital role in plant light protection (Peers et al ., 2009; Adamiec et al ., 2015; Wang et al ., 2020). Therefore, there has been substantial research on Lhc genes, particularly Lhcb2 and Lhcb1 in Arabidopsis (Leoni et al ., 2013).…”

Transcriptomic and Metabolomic Analyses Provide Insights Into an Aberrant Tissue of Tea Plant (Camellia sinensis)

“…Qubit and Agilent 2100 were used to construct nine RNA library (three tissues × three biological replicates) after filtering of the raw data. The filtering standards included adapter sequence removal via Adapter Removal version 2, quality filtering via the sliding window method, and length filtering via removal of sequences shorter than 50 bp ( Wang et al, 2020 ).…”

Transcriptomic Analyses Reveal Leaf Colour Changes and L-theanine Accumulation in Variegated Tea

“…A missing assembly of the trimeric LHCII results in no granum formation in the seedling lethal gdc1 mutant (grana-de cient chloroplast 1) [40]. The repressed expression of genes encoding LHCII is correlated with albinism in tea [14]. Without the light-harvesting complex LHCB6, PSII cannot properly organize PSII complexes in the membrane [41], which affects the structure and function of the granum membranes of chloroplasts [42].…”

“…The leaf colour changes in albino tea are mainly affected by chloroplast biogenesis and pigment biosynthesis. Numerous genes and signal integrators participate in chloroplast biogenesis [13], suppression of the etioplast-chloroplast transition and damage to grana in the chloroplast [10]; repression of genes encoding LHC [14] and expression of genes during protein processing can cause the leaf colour to change in tea [15]. Leaf colour changes are also largely in uenced by avonoid and carotenoid biosynthesis [16], the phenylpropanoid biosynthesis pathway [17], and the shikimic acid pathway [18].…”