Methods for grafting Arabidopsis thaliana and Eutrema salsugineum

Grafting, an ancient agronomic technique, is an artificial mode of asexual reproduction in plants. Recently, grafting research has gradually shifted from modifying agronomic traits to the study of molecular mechanism. Grafting is an excellent tool to study long-range signaling processes in plants. And the grafting between species will help elucidate the molecular mechanisms underlying contrasting differences between different species. Arabidopsis thaliana is a salt-sensitive model glycophyte and Eutrema salsugineum (previously Thellungiella salsuginea, salt cress) is a salt-tolerant model halophyte. Successful grafting of these two model plants will help further study the physiological and molecular mechanisms underlying salt tolerance in plants. The aim of this study was to demonstrate two sterile micro-grafting methods for Arabidopsis and salt cress.

We developed the methods for sterile grafting between A. thaliana and E. salsugineum; this is the first report on inter-generic grafting between Arabidopsis and Eutrema. The method involves cut-in grafting under sterile conditions. The grafted plant part was placed in half strength Murashige and Skoog medium with 1% agar and 1% sugar, and then cultured vertically with 22 °C/18 °C short-day/night cycles. The plants were then transferred to half strength Hoagland nutrient solution for hydroponics. The reported method is simple and easy to operate. Self-grafted Arabidopsis-Arabidopsis and Eutrema-Eutrema plants were used as controls, which were obtained with an improved hypocotyl-cutting grafting method. Ion contents in grafted plants were detected by inductively coupled plasma optical emission spectroscopy. The results showed that the ion content in salt cress and Arabidopsis changed to different degrees after grafting.

The inter-species grafting technique described here makes it possible to study hybrid plants between Arabidopsis and Eutrema and will contribute to further understanding of long-distance communications in plants. This technique also provides a reference for improving plant varieties using grafting, such as gardening plants, as well as fruit and vegetable crops.