Lotus tenuis x L. corniculatus interspecific hybridization as a means to breed bloat-safe pastures and gain insight into the genetic control of proanthocyanidin biosynthesis in legumes

BMC Plant Biology

Research Article

Pedro Carrasco¹  Francisco Marco²  Florencia M Babuin³  Oscar A Ruiz³  Fernando L Pieckenstain³  Francisco J Escaray³  Valentina Passeri⁴  Francesco Damiani⁴  Francesco Paolocci⁴ 

[1] Department of Biochemistry and Molecular Biology, Universitat de València, València, Spain;Department of Plant Biology, Universitat de València, València, Spain;IIB-INTECH/CONICET-UNSAM, Chascomús, Bs. As, Argentina;National Research Council, Institute of Biosciences and BioResources -Perugia (CNR-IBBR), Perugia, Italy;

关键词: Interspecific hybridization;    Lotus;    Proanthocyanidins (PAs);    TT2;    Forage legumes;    Nutritive value;   

DOI  :  10.1186/1471-2229-14-40

 received in 2013-07-25, accepted in 2014-01-17,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundProanthocyanidins (PAs) are secondary metabolites that strongly affect plant quality traits. The concentration and the structure of these metabolites influence the palatability and nutritional value of forage legumes. Hence, modulating PAs in the leaves of forage legumes is of paramount relevance for forage breeders worldwide. The lack of genetic variation in the leaf PA trait within the most important forage species and the difficulties in engineering this pathway via the ectopic expression of regulatory genes, prompted us to pursue alternative strategies to enhance this trait in forage legumes of agronomic interest. The Lotus genus includes forage species which accumulate PAs in edible organs and can thus be used as potential donor parents in breeding programs.ResultsWe recovered a wild, diploid and PA-rich population of L. corniculatus and crossed with L. tenuis. The former grows in an alkaline-salty area in Spain while the latter is a diploid species, grown extensively in South American pastures, which does not accumulate PAs in the herbage. The resulting interspecific hybrids displayed several traits of outstanding agronomic relevance such as rhizome production, PA levels in edible tissues sufficient to prevent ruminal bloating (around 5 mg of PAs/g DW), biomass production similar to the cultivated parent and potential for adaptability to marginal lands. We show that PA levels correlate with expression levels of the R2R3MYB transcription factor TT2 and, in turn, with those of the key structural genes of the epicatechin and catechin biosynthetic pathways leading to PA biosynthesis.ConclusionsThe L. tenuis x L. corniculatus hybrids, reported herein, represent the first example of the introgression of the PA trait in forage legumes to levels known to provide nutritional and health benefits to ruminants. Apart from PAs, the hybrids have additional traits which may prove useful to breed forage legumes with increased persistence and adaptability to marginal conditions. Finally, our study suggests the hybrids and their progeny are an invaluable tool to gain a leap forward in our understanding of the genetic control of PA biosynthesis and tolerance to stresses in legumes.

【 授权许可】

CC BY   
© Escaray et al.; licensee BioMed Central Ltd. 2014