Abstract: The present invention provides transgenic zoysiagrass plant cells transformed with a modified oat phytochrome A gene (S598A) in which the serine-598 codon was replaced with an alanine codon, which, when expressed, significantly suppresses shade avoidance reactions, such as dwarfish internodes and petioles, short leaves, increased branching, and dark-green leaf color. Said transgenic zoysiagrass shows a robust appearance and is expected to show enhanced resistance to biotic and abiotic stresses. Also provided are a recombinant DNA construct comprising the S598A gene which, when expressed, induces drastic suppression of shade avoidance reactions, transgenic plants produced by this method, and propagating seeds obtained from said transgenic plants.

Abstract: The present invention provides transgenic zoysiagrass plant cells transformed with a modified oat phytochrome A gene (S598A) in which the serine-598 codon was replaced with an alanine codon, which, when expressed, significantly suppresses shade avoidance reactions, such as dwarfish internodes and petioles, short leaves, increased branching, and dark-green leaf color. Said transgenic zoysiagrass shows a robust appearance and is expected to show enhanced resistance to biotic and abiotic stresses. Also provided are a recombinant DNA construct comprising the S598A gene which, when expressed, induces drastic suppression of shade avoidance reactions, transgenic plants produced by this method, and propagating seeds obtained from said transgenic plants.

Abstract: The present invention provides an efficient genetic transformation system for the zoysiagrass plant (Zoysia japonica Steud.). Also provided are optimized media compositions and culture conditions for the zoysiagrass transformation. The reliable transformation system for zoysiagrass was developed by optimizing several factors that significantly affect calli growth and plant regeneration. Callus type and co-cultivation period absolutely influenced the transformation efficiency. Concentrations of 2,4-D, CaCl2 and acetosyringone were also critical factors. The best result was achieved when type 3 calli were co-cultivated on a 2,4-D-free co-cultivation medium for 6 days. Removal of calcium and addition of 50 mg/liter acetosyringone during co-cultivation drastically enhanced the efficiency. The invention also provides a bialaphos-resistant zoysiagrass plant, which can be used in golf courses and athletic fields to save the maintenance cost.

Abstract: The present invention provides an efficient genetic transformation system for the zoysiagrass plant (Zoysia japonica Steud.). Also provided are optimized media compositions and culture conditions for the zoysiagrass transformation. The reliable transformation system for zoysiagrass was developed by optimizing several factors that significantly affect calli growth and plant regeneration. Callus type and co-cultivation period absolutely influenced the transformation efficiency. Concentrations of 2,4-D, CaCl2 and acetosyringone were also critical factors. The best result was achieved when type 3 calli were co-cultivated on a 2,4-D-free co-cultivation medium for 6 days. Removal of calcium and addition of 50 mg/liter acetosyringone during co-cultivation drastically enhanced the efficiency. The invention also provides a bialaphos-resistant zoysiagrass plant, which can be used in golf courses and athletic fields to save the maintenance cost.

Abstract: Fully differentiated higher plants may be regenerated from undifferentiated plant tissues, such as callus, derived from mature seeds, immature embryos, stems, roots, or leaves. The present invention provides a plant regeneration method from mature seed-derived calli. The regeneration procedure may include the induction of calli on the MS media containing 2 mg/L 2,4-dichlorophenoxyacetic acid and 0.2 mg/L 6-benzylaminopurine, 4 mg/L thiamine-HCl, and 100 mg/L &agr;-ketoglutaric acid. The plant regeneration efficiency is the highest when calli are grown on the MS media supplemented with 3% maltose and 1 mg/L 6-benzylaminopurine or 1 mg/L thidiazuron (TDZ). The invention can be utilized to introduce a gene or genes of agronomically important values into the zoysiagrass or possibly closely related turfgrass species.