Molecular cloning and expression analysis of Bro-GS-elong and Bro-myro from Brassica oleracea

The elongation factor GSL-Elong and myrosinase, which are essential for sulforaphane biosynthesis, were cloned for the first time from broccoli (Brassica oleracea var. italica) and were designated as Bro-GS-elong and Bro-myro. Sequence analysis of Bro-GS-elong and Bro-myro revealed that its full length cDNA was 1787 bp long and included a 1464 bp open reading frame encoding and 1846 bp long and included a 1647 bp open reading frame encoding, respectively. Bro-GS-elong and Bro-myro seem to be existed as members of multigene families in the broccoli genome and to be influenced by abiotic stresses and plant development. Bro-myro was preferentially expressed in reproductive organs, but the transcript levels of Bro-GS-elong were surpassed in vegetative organs. Both Bro-GS-elong and Bro-myro were strongly expressed at the period of sprouting, this result appeared to imply that Bro-GS-elong and Bro-myro may perform an important function in the early development on the quickly growing tissues and organs. The highest transcript levels of Bro-GS-elong and Bro-myro by MeJA treatment implied that glucosinolate- myrosinase system was primarily activated by jasmonates signaling. The results provide the basis for the glucosinolate-myrosinase system and the biotechnological manipulation of sulforaphane, a useful functional substance, in B. oleracea var. italica.