Production and transcriptional regulation of proanthocyanidin biosynthesis in forage legumes

Abstract

Proanthocyanidins (PA), also known as condensed tannins, contribute to important forage legumes traits including disease resistance and forage quality. PA in forage plants has both positive and negative effects on feed digestibility and animal performance. The analytical methods and their applicability in measuring the contents of PA in forage plants are essential to studies on their nutritional effects. In spite of important breakthroughs in our understanding of the PA biosynthesis, important questions still remain to be answered such as the PA polymerization and transport. Recent advances in the understanding of transcription factor-mediated gene regulation mechanisms in anthocyanin and PA biosynthetic pathway in model plants suggest new approaches for the metabolic engineering of PA in forage plants. The present review will attempt to present the state-of-the-art of research in these areas and provide an update on the production and metabolic engineering of PA in forage plants. We hope that this will contribute to a better understanding of the ways in which PA production to manipulate the content of PA for beneficial effects in forage plants.

The R2R3-MYB TT2b and the bHLH TT8 genes are the major regulators of proanthocyanidin biosynthesis in the leaves of Lotus species

“…PA accumulation in legume species is a complex, multigenic trait, with several, and likely species-specific, MYB factors that act within the MBW complex either as activators or repressors (Paolocci et al 2011;Albert 2015;Zhou et al 2015). Yet, the MBW complex is a gene network regulated by developmental signals and environmental determinants (Xie et al 2016).…”

“…(Yoshida et al 2010a;Verdier et al 2012;Hancock et al 2012). Nevertheless, studies in A. thaliana and other model species have shown that the accumulation of flavonoids is finely orchestrated by numerous regulatory genes, with MYB members of the MBW complex that act either as activators or repressor (Xu et al 2015;Zhou et al 2015).…”

Benefits of Condensed Tannins in Forage Legumes Fed to Ruminants: Importance of Structure, Concentration, and Diet Composition

“…The benefits of CTs have been demonstrated in only support the primary plant metabolism (Haslam, 1981). It is now well established that CT synthesis is under genetic control (Szczyglowski and Stougaard, 2008;Scioneaux et al, 2011;Cheynier et al, 2013;Escaray et al, 2014) and that expression depends on the plant species and plant parts (Larkin et al, 1997;Gebrehiwot et al, 2002;Abeynayake et al, 2012;Ferreyra et al, 2012;Hancock et al, 2012;Verdier et al, 2012;Cheynier et al, 2013;Harding et al, 2013;Mouradov and Spangenberg, 2014;Pérez-Díaz et al, 2014;Zhou et al, 2015;Zhu et al, 2015;Chezem and Clay, 2016).…”

Genome-Wide Identification and Comparative Analysis of MYB Transcription Factor Family in Musa acuminata and Musa balbisiana

“…Members of these groups are involved in several processes related to plant development [44]. In G4, MYB proteins from banana (MaMYB76 and MbMYB49) clustered with AtMYB04 (Figure 4), which is involved in flavonoid biosynthesis [50,51]. Similarly, AtMYB5 (shared clade with MaMYB17 and MbMYB135 in G5) is involved in regulating PA biosynthesis [52][53][54].…”