Genome-Wide Identification and Expression Analysis of R2R3-MYB Family Genes Associated with Petal Pigment Synthesis in Liriodendron

Abstract

The MYB transcription factor family is one of the largest families in plants, and its members have various biological functions. R2R3-MYB genes are involved in the synthesis of pigments that yield petal colors. Liriodendron plants are widely cultivated as ornamental trees owing to their peculiar leaves, tulip-like flowers, and colorful petals. However, the mechanism underlying petal coloring in this species is unknown, and minimal information about MYB genes in Liriodendron is available. Herein, this study aimed to discern gene(s) involved in petal coloration in Liriodendron via genome-wide identification, HPLC, and RT-qPCR assays. In total, 204 LcMYB superfamily genes were identified in the Liriodendron chinense genome, and 85 R2R3-MYB genes were mapped onto 19 chromosomes. Chromosome 4 contained the most (10) R2R3-MYB genes, and chromosomes 14 and 16 contained the fewest (only one). MEME analysis showed that R2R3-MYB proteins in L. chinense were highly conserved and that their exon-intron structures varied. The HPLC results showed that three major carotenoids were uniformly distributed in the petals of L. chinense, while lycopene and β-carotene were concentrated in the orange band region in the petals of Liriodendron tulipifera. Furthermore, the expression profiles via RT-qPCR assays revealed that four R2R3-MYB genes were expressed at the highest levels at the S3P/S4P stage in L. tulipifera. This result combined with the HPLC results showed that these four R2R3-MYB genes might participate in carotenoid synthesis in the petals of L. tulipifera. This work laid a cornerstone for further functional characterization of R2R3-MYB genes in Liriodendron plants.

Genome-Wide Comparative Analysis of the R2R3-MYB Gene Family in Five Solanaceae Species and Identification of Members Regulating Carotenoid Biosynthesis in Wolfberry

“…To date, members of the R2R3-MYB gene family have been identified and analyzed in different land plant species, including four Solanaceae species: tomato, potato, pepper, and eggplant. The number and composition of the R2R3-MYB gene family differ in different plants [29,34,35]. Ancient polyploidy events (also known as WGDs) and additional recent lineage-specific WGDs have presumably caused varying numbers of R2R3-MYB genes within land plants [46].…”

“…An increasing number of R2R3-MYB genes were recently identified in various plant species, including Arabidopsis (Arabidopsis thaliana), tomato (Solanum lycopersicum), pepper (Capsicum annuum), potato (Solanum tuberosum), plum (Prunus salicina), Chinese Bayberry (Morella rubra), tea (Camellia sinensis), Liriodendron, pineapple (Ananas comosus), Chinese pistache (Pistacia chinensis), and ginkgo (Ginkgo biloba) [28][29][30][31][32][33][34][35][36][37][38]. However, there are no reports about the R2R3-MYB gene family in wolfberry.…”

Identification and Expression Analysis of R2R3-MYB Family Genes Associated with Salt Tolerance in Cyclocarya paliurus

“…As one of the largest transcription factors in plants, MYB TFs possess a conserved DNA-binding domain constituted by one to four conserved repeats, whereas MYB superfamily genes can be divided into four types by reason of different incomplete MYB tandem repeat numbers [ 8 , 10 ]. MYB family genes have been identified in a large number of plants and the number varies among plants, such as Liriodendron chinense (204 MYB genes) [ 11 ], Avicennia marina (185 MYB genes) [ 12 ], Casuarina equisetifolia (182 MYB genes), and peach ( Prunus persica ) (155 MYB genes) [ 13 , 14 ]. Meanwhile, specific functions of MYB TFs including regulating development [ 15 , 16 , 17 ] and secondary metabolism [ 18 ], hormone signal transduction, and responding to abiotic stress have also been studied [ 19 , 20 ].…”

Genome-Wide Identification and Expression Analysis of SnRK2 Gene Family in Dormant Vegetative Buds of Liriodendron chinense in Response to Abscisic Acid, Chilling, and Photoperiod

“…Five ( Lchi13910 , Lchi00543 , Lchi25623 , Lchi12999 , and Lchi01348 ) SnRK2 family genes were discovered and confirmed using the L. chinense genome database and NCBI database ( ) (accessed on 5 June 2022) [ 44 , 45 , 46 ].…”

“…We used assembly/2630420, accessed on 5 June 2022, to determine the genome position and protein sequences of all L. chinense SnRK2 genes, and we assessed the distribution positions of SnRK2 genes on scaffold or chromosome. SnRK2 genes were found on the chromosomes of L. chinense using MapGene2Chromosome (MG2C; v2.0/) (accessed on 5 June 2022) [ 44 , 45 , 46 ].…”