Optimizing Regeneration Systems And Studies On Agrobacterium-mediated Transformation In Turfgrasses

In the present study, the factors which influenced plant regeneration from the mature seeds of Zoysia japonica 'Zenith', 'Songnan', 'Qingdao', Cynodon dactylon 'Jackpot', Agrostis palustris 'L-93', Festuca arundinacea 'Triple' and 'Starlet', Poe pratensis 'Fortuna' were evaluated to optimize plant regeneration system. The effect of four gelling agents , Phytagel (Sigma,St. Louis. USA), canageenen (co. zhongwei-SH., Shanghai), Agar A (Bio. Basic Inc., Canada) and Agar powder (China medicine (Group) Shanghai chemical reagent cooperation), on some turfgrasses embryogenic callus induction was compared systemically for the first time . The best gelling agent suitable for inducing embryogenic callus from each of the turfgrasses was confirmed. The effect of different concentrations of BA, KT, TDZ with 2 mg/L 2,4-D or dicamba on embryogenic callus induction form turfgrass was studied by the numbers , then the best combination of plant growth regulators was confirmed. In the meantime, the result that dicamba was not effective on the induction of callus from warm season turfgrasses was got. The highly regenerative embryogenic calli ( regeneration rate =90%) were induced from the mature seeds of Cynodon dactylon , and the regeneration rate was much higher than that in the only one report. The efficient Agrobacterium - mediated transformation system for Agrostis palustris and Zoysia japonica was established . With this system , transformation efficiency of Agrostis palustris and Zoysia japonica was 59% and 10-11%, which was far higher than the previous reports no matter what transformation methods they used. Putative transgenic plants of Agrostis palustris ,'Qingdao', 'Songnan' were got. The primary results were summarized as follows:1. In experiment 1,Phytagel was the best one of the four gelling agents to induce the embryogenic callus of Agrostis palustris, Poe pratensis, Cynodon dactylon. In the embryogenic callus induction of Zoysia japonica, four gelling agents have no significant differences except 'Qing dao'. Agar Powder is most efficient for callus induction from Festuca arundinacea.2. In experiment 2, 2,4-D was superior to dicamba for 'Zenith' callus induction. Low concentration of KT or TDZ obviously improved embryogenic callus induction of 'Zenith', however, higher concentrations inhibited callus formation. The optimized culture medium was MS +2 mg/L 2,4-D + 0.01 mg/L KT.