Preliminary Research On Regeneration And Transformation Of Broussonetia Papyrifera (L.) Vent

Broussonetia papyrifera (L.) Vent (common name: paper mulberry), an artificial tree belonging to family Moraceae, is an economically important species with salinity tolerance and drought hardiness. In China, Broussonetia papyrifera is used to make paper, however, up to now, there are no publications on the tissue culture using leaf or petiole explants or molecular engineering techniques in this species.As we all know, high salinity is one of the major abiotic stresses which constraints crop plant growth, development and productivity in many places in the world. To improve the tolerance of plants to high salinity has been an important goal for a long time. It has been shown previously that overexpression of AtNHX1 in Arabidopsis (a vacular Na~+/H~+ antiporter gene) conferred a higher salt tolerance.In this project, we standardized a single-step, high-frequency regeneration protocol for this woody plant using leaf and petiole explants derived from in vitro plantlets. Then by means of Agrobacterium mediated transformation, we introduced the salt tolerant AtNHXl gene into Paper Mulberry. At present, we have acquired some transgenic salt-tolerant Paper Mulberry plants of different lines. The presence of the inserted target gene has been checked by PCR. Further study on salt-tolerant experiments is undergoing.Meanwhile, we constructed a plant expression vector pBI121 (swpa2), which contains the salt tolerant AtNHXl gene. In the further research, we'd like to investigate the difference between the SWPA2 promoter and the 35S promoter.