The β-1,4-glucanase gene EuEG1 overexpression improve in vitro micrografting of Eucommia ulmoides

Abstract The difficulty of adventitious root formation poses a major constraint to the Eucommia ulmoides tissue culture and genetic transformation. Micrografting can provide a new way for in vitro transplantation of genetic transformation. This study used transgenic rootless test-tube seedlings as scions and seedlings from seed as rootstocks for micrografting to avoid the problem of rooting of tissue culture seedlings and study the role of EuEG1 gene in the graft healing process. In this study, it has verified that EuEG1 gene can improve in vitro micrografting of Eucommia ulmoides. Research has found that the overexpression of EuEG1 in transgenic plants (TP) being used as scions for micrografting presented a significantly higher survival rate than the wild-type (WT) and empty vector (EV) regenerated seedling scions. Paraffin section observation showed that more callus tissue appeared at the junction of transgenic scions, and the connection with the rootstock was more complete, which is beneficial for wound healing. The results give new insights into Eucommia ulmoides in vitro micrografting, and indicate that EuEG1 gene can promote wound healing and improve the grafting survival rate.