Tung tree is an oil-bearing woody plant species in the Euphorbiaceae family. The oil extracted from tung tree seeds, called tung oil, is an excellent dry oil, which is resistant to heat, cold, acid, alkali and corrosion, and has insulating properties. However, the molecular breeding of this species has been hampered by the lack of an efficient genetic transformation system.

Supervised by Dr. ZHANG Lingling of Wuhan Botanical Garden and Prof. ZHANG Lin from the Central South University of Forestry and Technology, JIA Hongyu developed a modified method for tung tree, and transgenic hairy roots could be effectively induced from the stem of tung tree seedling.

With the method, approximately 67% of the tung tree seedlings produced transgenic hairy roots with an average number of 10.71 hairy roots per seedling, and of these roots, approximately 13.96 % were transgenic.

This study firstly develops a root transgenic system in tung tree, and it is suitable for the hairy root induction of two other oil-bearing plants of the Euphorbiaceae family, Ricinus communis and Vernicia montana. This development of transgenic root systems allows gene function study by overexpression and silencing techniques or gene editing tools such as CRISPR/Cas9.

In conclusion, this technique can provide a convenient platform for the mining and identification of functional genes in tung tree, and benefit to the rapid development of molecular breeding in tung tree in the future. Besides, this method will provide a technical reference for other plants that are difficult to establish genetic transformation systems.

Results were published in Plants entitled “The first report on transgenic hairy root induction from the stem of tung tree (Vernicia fordii)”.

This work was supported by the Special Foundation for National Science and Technology Basic Research Program of China, National Natural Science Foundation of China, and the Youth Innovation Promotion Association of the Chinese Academy of Sciences. JIA Hongyu was the first author, and Dr. ZHANG Lingling and Prof. ZHANG Lin were the corresponding authors.

Induction and identification of transgenic hairy roots in the stem of tung tree seedling (Image by JIA Hongyu)