• Journal of Photoscience
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• 제9권2호
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• pp.329-331
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• 2002

There is a difference in the inhibitory effects to supplemental UVB (wavelengths 280 to 320 nm) among Japanese rice (Oryza sativa L.), the cultivar Norin I is less resistant while the cultivar Sasanishiki is resistant. UVB induces photodamage in DNA. Cyclobutane pyrimidine dimer (CPD) is a major UV-induced DNA lesion. Photorepair, which is mediated by photolyase, is the major pathway in plants for repairing CPD. We have analyzed CPD induction and repair in Sasanishiki and its close relative Norin I using alkaline agarose gel electrophoresis. Norin I is deficient in CPD photoreactivation and excision, thus UV sensitivity correlates with deficient dimer repair [I]. The photorepair deficiency in Norin I results from a functionally altered photolyase with a photoflash analysis [2]. In this paper, we examined the UVB-sensitivity of several other UV-sensitive and -resistant cultivars and found that the CPD photolyase activity was deficient in UV-sensitive ones. It was also evident that there was a variation in the deduced amino acid sequences of CPD photolyases of the UV-sensitive and -resistant cultivars, whereas each deduced amino acid sequence of the UV-sensitive cultivars and of the UV-resistant ones was the same. These results suggest that the difference in the CPD photolyases of UV-sensitive and -resistant rice might be due to the structural alteration of CPD photolyase.

• Journal of Photoscience
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• 제9권2호
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• pp.162-165
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• 2002

Rice is widely cultivated in various regions throughout Asia. Over a five-year period, we investigated the effects of supplemental UVB radiation on the growth and yield of Japanese rice cultivars in the field. The findings of that study indicated that supplemental UVB radiation has inhibitory effects on the growth and grain development. Furthermore, we investigated the sensitivity to UVB radiation of rice cultivars of 5 Asian rice ecotypes, and found that rice cultivars vary widely in UVB sensitivity. The aim of our study is improving UVB resistance in plants by bioengineering or breeding programs. In order to make it, there is need to find the molecular origin of the sensitivity to UVB. Cyclobutane pyrimidine dimer (CPD) is major UV-induced DNA lesions. Plants possess two mechanisms to cope with such DNA damage. The first is the accumulation of UV-absorbing compounds. Our previous data showed that the steady-state CPD levels in leaves of rice grown under chronic radiation in any culture were not so greatly influenced by the increased UV-absorbing compounds content, although there was a significant positive correlation between the CPD levels induced by challenge UVB exposure and the UV-absorbing compounds content. The other is the repair of DNA damage. Photorepair is the major pathway in plants for repairing CPD. We found that the sensitivity to UVB could seriously correlate with the low ability in CPD photorepair in rice plants. These results suggest that photo lyase might be an excellent candidate for restoration by way of selective breeding or engineering in rice.

• 한국식물생명공학회:학술대회논문집
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• 한국식물생명공학회 2004년도 생명공학 실용화를 위한 비젼
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• pp.29-34
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• 2004

Reduction in stratospheric ozone layer increases the amount of ultraviolet-B radiation (UVB: 280-320 nm) that reaches the earth ’ s surface. UVB radiationcan damage plants, resulting in decrease in growth and productivity. UVB-augmentation studies have indicated that the sensitivity to UVB radiation in plants varies among the species and cultivars. However. there are no definitive answers for the mechanisms of UVB-resistance in higher plants and for bioengineering design and development of UVB-tolerant plants. We have been studying physiological and biochemical aspects of the effects of UVB radiation on growth and yield of rice COryza sativa LJ. aiming to clarify the mechanism of resistance to UVB radiationin rice. At this meeting. weintroduce our research as followed: (1) supplementary UVB radiation has inhibitory effects on the growth. yield and grain development of rice; (2) UVB sensitivity of rice varies widely among cultivars; (3) among Japanese rice cultivars. Sasanishiki. a leading variety in northeast Japan. is more resistant to UVB. while Norin 1. a progenitor of Sasanishiki. is less resistant; (4)UV-sensitive Norin 1 cultivar is deficient in photorepair of UVB-induced cyclobutane pyrimidine dimer (CPD). and this deficiency results from one amino acid residue alteration of CPD photolyase. These results suggest that spontaneously occurring mutation in CPD photolyase gene could lead to difference in UVB sensitivity in rice. and that CPD photolyase might be a useful target for improving UVB-sensitivity in rice by selective breeding or bioengineering of UVB-tolerant rice.

• 생물환경조절학회지
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• 제10권3호
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• pp.197-206
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• 2001

오존층 파괴에 의해 지표면에 도달하는 자외선, 특히 UV-B(ultraviolet-B radiation, 280∼320nm)의 방사량이 증가하고 있다. UV-B는 유전자의 직접적인 손상, 호르몬 분해, 광합성 억제 등 생리·생화학적 대사기구에 영향을 미쳐 육상 생태계와 안정된 식량 확보에 큰 위협이 되고 있다. 그러나 식물은 UV-B에 대한 방어 기능을 갖고 있으며 형태적 적응, 광 회복 기능, UV-흡수물질의 생합성 촉진 등을 통해 UV-B로부터 생체를 보호한다.