Cell-cell adhesion in plant grafting is facilitated by β-1,4-glucanases.

Michitaka Notaguchi, Ken-Ichi Kurotani, Yoshikatsu Sato, Ryo Tabata, Yaichi Kawakatsu, Koji Okayasu, Yu Sawai, Ryo Okada, Masashi Asahina, Yasunori Ichihashi, Ken Shirasu, Takamasa Suzuki, Masaki Niwa, Tetsuya Higashiyama

Plant grafting is conducted for fruit and vegetable propagation, whereby a piece of living tissue is attached to another through cell-cell adhesion. However, graft compatibility limits combinations to closely related species, and the mechanism is poorly understood. We found that Nicotiana is capable of graft adhesion with a diverse range of angiosperms. Comparative transcriptomic analyses on graft combinations indicated that a subclade of β-1,4-glucanases secreted into the extracellular region facilitates cell wall reconstruction near the graft interface. Grafting was promoted by overexpression of the β-1,4-glucanase. Using Nicotiana stem as an interscion, we produced tomato fruits on rootstocks from other plant families. These findings demonstrate that the process of cell-cell adhesion is a potential target to enhance plant grafting techniques.