Multiple bHLH/MYB-based protein complexes regulate proanthocyanidin biosynthesis in the herbage of Lotus spp.

Autor: Escaray FJ; Instituto de Biología Molecular de Plantas (IBMCP) Universitat Politécnica de València - C.S.I.C, Ciudad Politécnica de la Innovación, Edificio 8E, Ingeniero Fausto Elio, s/n, 46022, Valencia, Spain., Valeri MC; Institute of Biosciences and BioResources (IBBR), Consiglio Nazionale Delle Ricerche, Via Madonna Alta, 130, 06128, Perugia, Italy., Damiani F; Institute of Biosciences and BioResources (IBBR), Consiglio Nazionale Delle Ricerche, Via Madonna Alta, 130, 06128, Perugia, Italy., Ruiz OA; Unidad de Biotecnología 1, Instituto Tecnológico de Chascomús (INTECh), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Avenida Intendente Marino KM 8.2, 7130, Chascomús, Buenos Aires, Argentina., Carrasco P; Biotecmed, Department of Biochemistry and Molecular Biology, University of València, 46100, Burjassot, Valencia, Spain., Paolocci F; Institute of Biosciences and BioResources (IBBR), Consiglio Nazionale Delle Ricerche, Via Madonna Alta, 130, 06128, Perugia, Italy. francesco.paolocci@ibbr.cnr.it.
Jazyk: angličtina
Zdroj: Planta [Planta] 2023 Dec 02; Vol. 259 (1), pp. 10. Date of Electronic Publication: 2023 Dec 02.
DOI: 10.1007/s00425-023-04281-2
Abstrakt: Main Conclusion: The complexes involving MYBPA2, TT2b, and TT8 proteins are the critical regulators of ANR and LAR genes to promote the biosynthesis of proanthocyanidins in the leaves of Lotus spp. The environmental impact and health of ruminants fed with forage legumes depend on the herbage's concentration and structure of proanthocyanidins (PAs). Unfortunately, the primary forage legumes (alfalfa and clover) do not contain substantial levels of PAs. No significant progress has been made to induce PAs to agronomically valuable levels in their edible organs by biotechnological approaches thus far. Building this trait requires a profound knowledge of PA regulators and their interplay in species naturally committed to accumulating these metabolites in the target organs. Against this background, we compared the shoot transcriptomes of two inter-fertile Lotus species, namely Lotus tenuis and Lotus corniculatus, polymorphic for this trait, to search for differentially expressed MYB and bHLH genes. We then tested the expression of the above-reported regulators in L. tenuis x L. corniculatus interspecific hybrids, several Lotus spp., and different L. corniculatus organs with contrasting PA levels. We identified a novel MYB activator and MYB-bHLH-based complexes that, when expressed in Nicotiana benthamiana, trans-activated the promoters of L. corniculatus anthocyanidin reductase and leucoanthocyanidin reductase 1 genes. The last are the two critical structural genes for the biosynthesis of PAs in Lotus spp. Competition between MYB activators for the transactivation of these promoters also emerged. Overall, by employing Lotus as a model genus, we refined the transcriptional network underlying PA biosynthesis in the herbage of legumes. These findings are crucial to engineering this trait in pasture legumes.
(© 2023. The Author(s).)
Databáze: MEDLINE
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