Transcriptome Analysis of Drought Resistance in Japanese Lawn Grass (Zoysia japonica Steud.)

With the intensification of global climate change, the increasing frequency and severity of extreme weather events seriously affected agroecosystems and human health. Zoysia japonica Steud. (Z. japonica) is a warm season turfgrass with outstanding drought tolerance; therefore, gaining insight into the breeding and ecological restoration of drought-tolerant lawn grass species is of great significance. This study aimed to investigate the adaptive strategies of drought-resistant z047 and z388 by integrating transcriptome analysis and experimental physiological measurements in a drought field. Physiological experiments have demonstrated that z047 plants exhibited a stronger water retention capacity, lower cell membrane damage, and higher above-ground biomass. In addition, the relative water content and permanent wilting coefficient of z047 plants were superior to wild type plants. Our results verified that there were 108 and 208 significantly differentially expressed genes (DEGs) (fold change (FC) ≥ 4, p < 0.01) screened from z047 plants under drought stress for 7 and 14 days, respectively. Moreover, remarkable upregulation of MAPKKK17 and MAPKKK16 genes involved in the MAPK signalling pathway may be closely related to their drought tolerance. Collectively, this study reveals the molecular and physiological synergistic mechanism of drought tolerance in Z. japonica, thus providing a theoretical basis for molecular breeding of drought-tolerant plant cultivars and ecological restoration in arid areas.