Genetic analysis of the raffinose oligosaccharide pathway in lentil seeds

Two lentil (Lens culinaris) cultivars, Syrian Local Large (SLL) and PANT-L- 406 (PL), have been used to study the genetics of the raffinose family of o ligosaccharides (RFO) and a related compound, ciceritol, which is a galacto syl cyclitol, The RFO and ciceritol are the major soluble alpha-galactoside s in lentil seeds. Crosses were made between the two lentil lines and the p atterns of inheritance for the total alpha-galactoside content and for indi vidual RFO compounds (raffinose, stachyose, verbascose) and ciceritol were determined in the embryos and seed coats from single seeds of the reciproca l F(1)s, the F(2)s and ten F-3 families. The inheritance patterns for each of the alpha-galactosides were complex and much of this complexity was attr ibuted to an interaction between the embryo and its surrounding testa. A cl ear-cut segregation pattern was observed for verbascose, This was the resul t of PL embryos having very low, or no, verbascose. The F-2 embryos had a s egregation ratio of 3 high to 1 low level for this compound, suggesting tha t within this cross a low verbascose content was determined by a single rec essive gene. There was good evidence from the F-2 and F-3 generations of a negative correlation between low levels of verbascose and high levels of ci ceritol, which suggests a metabolic link between the RFO pathway and the pa thway leading to ciceritol. The data are discussed in terms of defining str ategies for genetically manipulating the alpha-galactoside composition in l entil seeds, such that their negative effects on nutrition may be overcome without reducing significantly their positive role in abiotic stress resist ance.