벼 엽록체 small HSP의 과발현에 의한 형질전환 식물체의 내열성 증가 = Overexpression of Rice Chloroplast Small Heat Shock Protein Increases Thermotolerance in Transgenic Plants

다국어 초록 (Multilingual Abstract)

To investigate the function of chloroplast small heat shock protein (HSP), transgenic tobacco plants (Nicotiana tabacum L, cv. SR-1) that constitutively overexpress the rice chloroplast small HSP (Oshsp26) were generated. Effects of constitutive expression of the Oshsp26 on thermotolerance were investigated with the chlorophyll fluorescence. After 5-min incubation of leaf discs at high temperatures, an increase in the Fo level, indication of separation of LHCII from PSII, was mitigated by constitutive expression of the chloroplast small HSP. When tobacco plantlets grown in Petri dishes were incubated at 52℃ for 45 min and subsequently incubated at 25℃, leaf color of wild-type plant became gradually white and all plantlets were finally died. Under the conditions in which all the wild-type plants died, more than 80% of the transformants remained green and survived. It was also found that the levels of Oshsp26 protein accumulated in transgenic plants were correlated with the degree of thermotolerance. These results suggest that the chloroplast small HSP plays an important role in protecting photosynthetic machinery, as a results, increases thermotolerance of whole plant during heat stress.