|Budget Amount *help
¥3,700,000 (Direct Cost : ¥3,700,000)
Fiscal Year 2005 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 2004 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 2003 : ¥2,100,000 (Direct Cost : ¥2,100,000)
First, we investigated photosynthesis abilities of several wild species of genus Oryza. According to the results, O.australiensis, which has EE genome, showed the higher efficiency than a cultivated species, O.sativa, which has AA genome. Nevertheless, the DNA sequence of Rubisco activase gene that activates Rubisco, which is considered as a limiting factor for photosynthesis rates, was insignificantly similar to the one of O.sativa (their homology was 98%).
Next, O.sativa L.cv.Nipponbare was transformed with rice Rubisco activase gene driven by Cab promoter via Agrobacterium. We obtained several dozen transgenic plants. However, their Rubisco activase contents were much lower than that of the wild type probably because of the severe co-suppressions. Therefore we have not created over-expressing transgenic plants of Rubisco activase.
Meanwhile, we also obtained antisense Rubisco activase introduced transgenic rice plants. Our research showed that 20 - 25% of regular Rubisco activase contents could keep the normal photosynthesis rate under a stable high light condition, but it would not enough if they were under variable light conditions.
Now we are continuing some plans to utilize other species, such as barley, corn, spinach, bean, or another promoter, CAMV35S, instead of Cab promoter and to introduce them into rice plants.