Peanut LEAFY COTYLEDON1-type genes participate in regulating the embryo development and accumulation of the storage lipids

Abstract

Abstract LEAFY COTYLEDON1 (LEC1) belongs to a member of nuclear factor Y (NF-Y) transcription factors, which has been identified as a key regulator of embryo development. In present study, two LEC1-type genes from Arachis hypogeae were identified and designated as AhNF-YB1 and AhNF-YB10 which belong to subgenome A and subgenome B, respectively. The functions of AhNF-YB1 and AhNF-YB10 were investigated by complementary analysis of their defective phenotypes in Arabidopsis lec1-2 mutant and their ectopic expressions in wild-type Arabidopsis. The results indicated that both AhNF-YB1 and AhNF-YB10 take part in regulating embryogenesis, embryo development, and reserves deposition in cotyledon, and they have partial function redundancy. A bit differently, AhNF-YB10 could complement almost all defective phenotypes of lec1-2, in the embryonic morphology and the length of hypocotyl, while AhNF-YB1 only in part. And 30%-40% seeds of the AhNF-YB1 transformants showed the decreasing germination ratio and longevity. Therefore, the appropriate spatio-tempoeal expression of these genes is necessary for embryo morphogenesis at early development stage and is responsible for seeds maturation at mid-late development stage. On the other hand, overexpression of AhNF-YB1 or AhNF-YB10 at the middle to late stages of seed development in Arabidopsis could improve the weight, the oil content, and fatty acid component of transgenic seeds. In the meanwhile, the expression levels of some genes associated with fatty acid synthesis and embryogenesis in developing AhNF-YB10-overexpression seeds were significantly enhanced. This study will provide the theoratic basis for oilseed crops breeding of high yields and high oil content.