Functional MYB transcription factor gene HtMYB2 is associated with anthocyanin biosynthesis in Helianthus tuberosus L

Abstract

Background: Tuber color is an important trait for Helianthus tuberosus L. (Jerusalem artichoke). Usually, purple tubers with high anthocyanin content are more nutritious than white tuber. But, the molecular mechanism underlying it is unknown. Results: In the current study, high-throughput RNA-sequencing was used to compare the transcriptomes between plants with tubers with red or white epidermis. Compared with the white-skinned tubers of cultivar QY3, anthocyanin biosynthesis structural genes had greater expression in the red-skinned tubers of cultivar QY1, indicating that the anthocyanin biosynthesis pathway was activated in 'QY1'; quantitative PCR confirmed this difference in expression. HtMYB2 (Unigene44371_All) was the only MYB transcription factor, homologous to the MYB transcription factor regulating anthocyanin biosynthesis, expressed in the red tuber epidermis of 'QY1'. The anthocyanin concentration in the root, stem, leaf, flower, and tuber epidermis of 'QY1' was higher than in 'QY3', especially tuber epidermis. Correspondingly, HtMYB2 had greater expression in these tissues of 'QY1' than in 'QY3'. The expression of HtMYB2 was associated with anthocyanin accumulation in the different tissues. Overexpression of HtMYB2 activated the anthocyanin biosynthesis pathway, accumulating the pigment in leaves of transgenic tobacco, supporting the model that HtMYB2 regulated anthocyanin biosynthesis. Further experiments found that HtMYB2 had the same coding sequence and genomic sequence in 'QY1' and 'QY3', but that there were several single nucleotide polymorphisms and one insertiondeletion (indel) mutation of 21 nucleotides in the promoter region between the two alleles. The deletion of three nucleotides "AAA" made the promoter of 'QY1' predicted to contain one more possible promoter region. A specific primer, based on the indel, could differentiate between cultivars with red or white tuber epidermis. The genetic variation in HtMYB2 was associated with the tuber skin color in a natural population. Conclusions: RNA-seq can successfully isolate the candidate gene (HTMYB2) controlling anthocyanin biosynthesis in purple epidermis of Jerusalem artichoke tuber. HTMYB2 can regulate anthocyanin biosynthesis in plants and is closely related to the formation of purple phenotype in tubers. This study should be useful in understanding the genetic mechanism underlying different tuber skin colors and in breeding new H. tuberosus cultivars with different tuber skin colors.

AcMYB1 Interacts With AcbHLH1 to Regulate Anthocyanin Biosynthesis in Aglaonema commutatum

“…Tobacco is one of the most widely studied model plants in verifying the functions of anthocyanin regulators (Vimolmangkang et al, 2013 ; Huang et al, 2016 ; Zhao et al, 2022 ). For example, HtMYB2 (Gao et al, 2020 ), EsMYB9 (Huang et al, 2017 ), AaMYB2 (Li et al, 2016 ), and IbMYB1a (An et al, 2015 ) were found to regulate tobacco anthocyanin biosynthesis to varying degrees. Similarly, in this study, overexpression of AcMYB1 in tobacco displayed striking changes in anthocyanin accumulation in both vegetative and reproductive tissues at various developmental stages ( Figures 6A–L ).…”

Functional R2R3-MYB Transcription Factor NsMYB1, Regulating Anthocyanin Biosynthesis, Was Relative To The Fruit Color Differentiation in Nitraria Sibirica Pall

“…The promoter sequences of NsMYB1 were isolated from RF and BF by Thermal asymmetric interlaced polymerase chain reaction (TAIL-PCR) [50]. The functional domain in NsMYB1 promoter sequences were analyzed based on BDPG (http://www.fruit y.org/seq tools/promoter.html) [51].…”

Characterization of Highbush Blueberry (Vaccinium corymbosum L.) Anthocyanin Biosynthesis Related MYBs and Functional Analysis of VcMYB Gene

“…Based on the genome data, Wang et al [31] identified a total of 229 MYB members that could be further divided into 23 subfamilies, but they did not focus on the anthocyanin biosynthesis related members; Zhao et al [17] identified 11 MYBs from blueberry fruits through homologous protein searching, using Arabidopsis, apple, grape and strawberry MYBs belonging to the MBW complex as queries. Recently, many ABRMs have been identified and functionally approved in various plant species, such as Arabidopsis [36], Helianthus tuberosus [37], monkeyflower [38], Eutrema salsugineum [39], Freesia hybrida [40], grape hyacinth [41], apple [42] and so on. In this study, for the exploration and characterization of blueberry ABRMs, we identified the blueberry ABRMs by homologous searches against the blueberry protein data provided by the highbush blueberry genome project using the reported ABRMs from some other plant species as queries, characterized their sequences, and investigated their corresponding genes' expression patterns in blueberry fruits at five different ripening stages, based on our previously obtained transcriptome data and quantitative real time PCR (qRT-PCR) analysis.…”