RRC ID 68949
Author Kim S, Song H, Hur Y.
Title Intron-retained radish (Raphanus sativus L.) RsMYB1 transcripts found in colored-taproot lines enhance anthocyanin accumulation in transgenic Arabidopsis plants.
Journal Plant Cell Rep
Abstract KEY MESSAGE:Overexpression of the naturally occurring intron-retained (IR) forms of radish RsMYB1 and RsTT8 transcripts in Arabidopsis causes a substantial increase in anthocyanin accumulation. The production of anthocyanins in plants is tightly controlled by the MYB-bHLH-WD40 (MBW) complex. In this study, analysis of four radish (Raphanus sativus L.) inbred lines with different colored taproots revealed that regulatory genes of anthocyanin biosynthesis, RsMYB1 and RsTT8, produce three transcripts, one completely spliced and two intron retention (IR1 and IR2) forms. Transcripts RsMYB1-IR1 and RsMYB1-IR2 retained the 1st (380 nt) and 2nd (149 nt) introns, respectively; RsTT8-IR1 retained the 4th intron (113 nt); RsTT8-IR2 retained both the 3rd (128 nt) and 4th introns. Levels of most IR forms were substantially low in radish samples, but the RsTT8-IR2 level was higher than RsTT8 in red skin/red flesh (RsRf) root. Since all IR forms contained a stop codon within the intron, they were predicted to encode truncated proteins with defective interaction domains, resulting in the inability to form the MBW complex in vivo. However, tobacco leaves transiently co-expressing RsMYB1-IRs and RsTT8-IRs showed substantially higher anthocyanin accumulation than those co-expressing their spliced forms. Consistently, co-expression of constructs encoding truncated proteins with spliced or IR forms of their interaction partner in tobacco leaves did not result in anthocyanin accumulation. Compared with RsMYB1, the overexpression of RsMYB1-IRs in Arabidopsis pap1 mutant increased anthocyanin accumulation by > sevenfold and upregulated the expression of Arabidopsis flavonoid biosynthesis genes including AtTT8. Our results suggest that the stable co-expression of RsMYB1-IRs in fruit trees and vegetable crops could be used to increase their anthocyanin contents.
Volume 40(9)
Pages 1735-1749
Published 2021-9-1
DOI 10.1007/s00299-021-02735-z
PII 10.1007/s00299-021-02735-z
PMID 34308490
MeSH Alternative Splicing Anthocyanins / metabolism* Arabidopsis / genetics Arabidopsis / metabolism* Gene Expression Regulation, Plant Introns Pigmentation / genetics Plant Leaves / genetics Plant Proteins / genetics* Plant Proteins / metabolism Plant Roots / genetics Plant Roots / metabolism Plants, Genetically Modified / genetics Plants, Genetically Modified / metabolism* Raphanus / genetics* Tobacco / genetics
IF 3.825
Arabidopsis / Cultured plant cells, genes pst16228