Analysis of a radiation-induced dwarf mutant of a warm-season turf grass reveals potential mechanisms involved in the dwarfing mutant

Abstract

Zoysia matrella [L.] Merr. is a widely cultivated warm-season turf grass in subtropical and tropical areas. Dwarf varieties of Z. matrella are attractive to growers because they often reduce lawn mowing frequencies. In this study, we describe a dwarf mutant of Z. matrella induced from the 60Co-γ-irradiated calluses. We conducted morphological test and physiological, biochemical and transcriptional analyses to reveal the dwarfing mechanism in the mutant. Phenotypically, the dwarf mutant showed shorter stems, wider leaves, lower canopy height, and a darker green color than the wild type (WT) control under the greenhouse conditions. Physiologically, we found that the phenotypic changes of the dwarf mutant were associated with the physiological responses in catalase, guaiacol peroxidase, superoxide dismutase, soluble protein, lignin, chlorophyll, and electric conductivity. Of the four endogenous hormones measured in leaves, both indole-3-acetic acid and abscisic acid contents were decreased in the mutant, whereas the contents of gibberellin and brassinosteroid showed no difference between the mutant and the WT control. A transcriptomic comparison between the dwarf mutant and the WT leaves revealed 360 differentially-expressed genes (DEGs), including 62 up-regulated and 298 down-regulated unigenes. The major DEGs related to auxin transportation (e.g., PIN-FORMED1) and cell wall development (i.e., CELLULOSE SYNTHASE1) and expansin homologous genes were all down-regulated, indicating their potential contribution to the phenotypic changes observed in the dwarf mutant. Overall, the results provide information to facilitate a better understanding of the dwarfing mechanism in grasses at physiological and transcript levels. In addition, the results suggest that manipulation of auxin biosynthetic pathway genes can be an effective approach for dwarfing breeding of turf grasses.

A Survey of Enhanced Cold Tolerance and Low-Temperature-Induced Anthocyanin Accumulation in a Novel Zoysia japonica Biotype

“…Whole transcriptome analysis based on next-generation sequencing technologies has developed as a useful approach for finding and identifying genes involved in abiotic stress resistance in recent years, drastically enhancing our understanding of the interaction between plant and environment. To date, the NCBI database holds 11 transcriptomic BioProjects for Zoysia species, including 8 for Z. japonica , 2 for Z. matrella [ 7 , 8 ], and 1 for Z. macrostachya [ 9 ]. Among the eight transcriptomic studies on Z. japonica , two focused on spike pigmentation [ 10 ], one on responses to pathogen invasion [ 11 ], and the others on responses to abiotic stresses, including aluminum, wounding [ 12 ], salt [ 13 , 14 ] and low-temperature [ 15 ].…”

Metabolomics and Hormone Level Analysis of Seashore paspalum Dwarf Mutant T51

“…The research on the mechanism of plant dwarfing mainly focuses on crops such as rice [21,22], wheat [23,24], maize [25,26], soybean [27,28] and cotton [29,30]. At present, the dwarfing mechanism of lawn grass, such as Zoysia matrella [31] and Kentucky Bluegrass [32], has been studied. However, there is no relevant report on the dwarfing mechanism of seashore paspalum.…”