Isolation of development-related genes in somatic embryo radicle of carrot(Daucus carota L.) using modified cDNA RDA

Using modified cDNA RDA capitalizing on the high affinity of streptavidin f or biotin and magnetic-absorption-based separation, we have obtained four b ands of specifically expressed cDNA in the carrot somatic embryo deregulate d for 12 h, which were designated as NR-1, NR-2, NR-3 and NR-4, respectivel y. As revealed by homology analysis of their DNA sequences after cloning th em into pBS, remarkable homology was demonstrated in NR-2, NR-3 and NR-4 wi th the genes coding for LEA (late embryogenesis abundant protein), Dna J an d xyloglucan endo-trans-glycosylase in plants. On the other hand, NR-1 show ing no homology with any known sequence may have come from unknown genes. U sing P-32-labeled NR-1 as probe, hybridization with cDNA fragment populatio n has shown that we have actually cloned a new gene fragment related to rad icle development. As shown by further Southern hybridization, these genes m ay be present in carrot genome in the form of single or low copies.