Effects Of The Introduced METR And Ipt Genes On Plant Growth & Development And Stress Resistance In Rice

Rice is one of the most important cereal crops. Ethylene and Cytokinin are very important for plant growth and development, which are related with response to environmental stimuli. In our previous studies, two genes respecially related to the above two hormones, mETR (a mutant gene of ethylene receptor gene ETR1 from Arabidopsis) and Ipt (one important gene which encoding the key enzyme in Cytokinin synthesis in Agrobacteria tumefaciens) were transferred into one rice cultivar. In present study, some selected transgenic rice lines containing the homozygous foreign gene(s) were used to investigate their characterizations, such as the resistance to biotic or abiotic environment, which are all related with plant hormones ethylene and Cytokinin. The main results are showed as followings.1. In the case of plant growth and development, some transgenic rice lines showed significant difference when comparing with those of wildtype, such as decrease of leave area, leaf weight and leaf weight per unit of leaf area, decrease of grain number per panicle; some ttansgenic rice lines showed significant difference, such as plant height of ripen stage, delayed heading stage and leaf senescence, increase of chlorophyll content in leaf.2. The results from analyses during abiotic stress showed that some transgenic rice lines were better on drought resistance. In details, some transgenic lines showed decrease of heading stage delaying, decrease of chlorophyll content losing. On the other hand, decrease of shoot number and root number dcreasing. Under salt stress, some of the transgenic lines grown better than wildtype. 3. In the case of biotic resistance, most of the transgenic rice lines showed more resistant than wildtype, in particular, with shorter disease spot, relative disease spot and disease speckles in bacterial leaf spot.