Condensed Tannins in White Clover ( Trifolium repens ) Foliar Tissues Expressing the Transcription Factor TaMYB14-1 Bind to Forage Protein and Reduce Ammonia and Methane Emissions in vitro .

Autor:	Roldan MB; Grasslands Research Centre, AgResearch Ltd, Palmerston North, New Zealand., Cousins G; PGG Wrightson Seeds Ltd, Palmerston North, New Zealand., Muetzel S; Grasslands Research Centre, AgResearch Ltd, Palmerston North, New Zealand., Zeller WE; ARS-USDA, US Dairy Forage Research Center, Madison, WI, United States., Fraser K; Grasslands Research Centre, AgResearch Ltd, Palmerston North, New Zealand.; Riddet Institute, Massey University, Palmerston North, New Zealand., Salminen JP; Natural Chemistry Research Group, University of Turku, Turku, Finland., Blanc A; PGG Wrightson Seeds Ltd, Palmerston North, New Zealand.; AgroParis Tech, Paris, France., Kaur R; PGG Wrightson Seeds Ltd, Palmerston North, New Zealand., Richardson K; Grasslands Research Centre, AgResearch Ltd, Palmerston North, New Zealand., Maher D; Grasslands Research Centre, AgResearch Ltd, Palmerston North, New Zealand., Jahufer Z; Grasslands Research Centre, AgResearch Ltd, Palmerston North, New Zealand., Woodfield DR; PGG Wrightson Seeds Ltd, Palmerston North, New Zealand., Caradus JR; Grasslanz Technology Ltd, Palmerston North, New Zealand., Voisey CR; Grasslands Research Centre, AgResearch Ltd, Palmerston North, New Zealand.
Jazyk:	angličtina
Zdroj:	Frontiers in plant science [Front Plant Sci] 2022 Jan 06; Vol. 12, pp. 777354. Date of Electronic Publication: 2022 Jan 06 (Print Publication: 2021).
DOI:	10.3389/fpls.2021.777354
Abstrakt:	Grazing ruminants contribute to global climate change through enteric methane and nitrous oxide emissions. However, animal consumption of the plant polyphenolics, proanthocyanidins, or condensed tannins (CTs) can decrease both methane emissions and urine nitrogen levels, leading to reduced nitrous oxide emissions, and concomitantly increase animal health and production. CTs are largely absent in the foliage of important temperate pasture legumes, such as white clover ( Trifolium repens ), but found in flowers and seed coats. Attempts at enhancing levels of CT expression in white clover leaves by mutagenesis and breeding have not been successful. However, the transformation of white clover with the TaMYB14-1 transcription factor from Trifolium arvense has resulted in the production of CTs in leaves up to 1.2% of dry matter (DM). In this study, two generations of breeding elevated foliar CTs to >2% of DM. The CTs consisted predominantly of prodelphinidins (PD, 75-93%) and procyanidins (PC, 17-25%) and had a mean degree of polymerization (mDP) of approximately 10 flavan-3-ol subunits. In vitro studies showed that foliar CTs were bound to bovine serum albumin and white clover proteins at pH 6.5 and were released at pH 2.-2.5. Using rumen in vitro assays, white clover leaves containing soluble CTs of 1.6-2.4% of DM significantly reduced methane production by 19% ( p ≤0.01) and ammonia production by 60% ( p ≤ 0.01) relative to non-transformed wild type (WT) controls after 6 h of incubation. These results provide valuable information for further studies using CT expressing white clover leaves for bloat prevention and reduced greenhouse gas emissions in vivo . Competing Interests: JC is employed by Grasslanz Technology Ltd., who owns the patent for the TaMYB14 transcription factor. DW was the primary breeder involved with the development of the cultivar “Grasslands Mainstay” and is employed by PGG Wrightson Seeds Ltd., who will have the exclusive license from Grasslanz Technology Ltd for use of TaMYB14 in white clover. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. (Copyright © 2022 Roldan, Cousins, Muetzel, Zeller, Fraser, Salminen, Blanc, Kaur, Richardson, Maher, Jahufer, Woodfield, Caradus and Voisey.)
Databáze:	MEDLINE
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