Establishment of Agrobacterium-mediated genetic transformation and CRISPR/Cas9-guided gene editing in Elymus nutans

Elymus nutans, an allohexaploid (2n = 6x = 42) species with a StStHHYY genome, is a native perennial in the alpine grasslands of the Qinghai-Xizang Plateau, and has been widely used for artificial pasture and ecological restoration as a forage grass with highest yield on the plateau. Nevertheless, the lack of a stable transformation system has impeded further efforts to trait improvement of E. nutans. In the present study, we established a reliable Agrobacterium-mediated genetic transformation system for E. nutans, and successfully generated EnTCP4-edited plants using the CRISPR/Cas9 system. The editing efficiency achieved 19.23 % in E. nutans. Knocking out EnTCP4 significantly delayed flowering and enhanced water-deficit stress resistance. This research represents a significant breakthrough in the genetic transformation and gene editing of E. nutans, laying a technological foundation to gain insight into gene functions and molecular breeding in E. nutans.