ZjSGR gene editing of Zoysia japonica using the CRISPR/Cas9 system

Zoysia grass (Zoysia japonica) is a common warm-season turfgrass and forage grass species with many excellent characteristics. However, early leaf de-greening occurs in northern parts of China in late autumn and early winter. This limiting factor restricts the wide usage of Zoysia japonica. ZjSGR, a senescence inducing gene isolated from Zoysia grass, plays a negative role in the Zoysia grass leaf color retention process. In this study, the CRISPR/Cas9 system was used to edit the ZjSGR gene of Zoysia japonica by particle bombardment transformation. One ZjSGR mutant plant was obtained after sequencing verification. The mutant plants which appeared dark green had a higher concentration of chlorophyll under natural conditions (28～30 ℃) compared to wild-type plants (P < 0.05). This study provides plant materials for further functional studies of the ZjSGR gene. The mutant plants are a valuable germplasm for the stay-green type Zoysia grass breeding program.