Influences of <i>Agrobacterium rhizogenes</i> strains, plant genotypes, and tissue types on the induction of transgenic hairy roots in <i>Vitis</i> species

Abstract

In this study, we evaluated the influences of 3 Agrobactrium rhizogenes strains (15384, A4, and K599), 4 different tissue types (internodes, stem-cut and petiole-cut surfaces on in vitro plants, and young shoots excised from in vitro plants), and 14 Vitis species (Vitis cinerea, V. champinii, V. doaniana, V. ficifolia, V. flexuosa, V. girdiana, V. jacquemontii, V. labrusca, V. nesbittiana, V. novae-angliae, V. palmata, V. piasezkii, V. treleasii, and V. vinifera) on the induction of transgenic hairy roots. Our results revealed that both 15834 and A4, but not K599, were effective in inducing hairy roots in Vitis species and that different Vitis species and tissue types responded differently to hairy root induction. Among the 14 species evaluated, V. champinii, V. cinerea, V. labrusca, V. treleasii, and V. vinifera-1044 produced hairy roots within a 2-week observation period when the induction was carried out on in vitro plants. Compared with the tissues of stem-cut and petiole-cut surface, the internode tissue showed a higher efficiency for hairy root induction. We further revealed that when young shoots were excised from in vitro plants and used as inoculation material, the overall induction efficiency of hairy roots could be much improved. In addition, we also investigated the feasibility of producing composite plants with transgenic hairy roots and non-transgenic shoots. Although a number of such in vitro composite plants were established from inoculated young shoots, none of them were successfully maintained after being transplanted to pot soil.