Physiological Response of OsHSP26 Overexpressed Transgenic Poplar(Populus alba L.) on Temperature Stress

Abstract

The ability of plants to endure environmental stress factors, which are going to be moresevere due to global warming, is important especially for forest plants. Because obtain trait ofresistance to temperature using conventional breeding for woody plants is a time consumingway. In this study, chloroplast-localized OsHSP26 gene was overexpressed in Populus alba L. tobreed tolerant transgenic poplar to temperature stress. The plantlets of OsHSP26-overexpressedtransgenic poplar showed more heathy phenotypic response than wild-type plants under bothprolonged low- and high-temperature stress. While the SPAD value, which refers chlorophyllcontent, in wild-type plants decreased depending on the exposure time to the temperature stress,higher SPAD value were shown in the transgenic plants. The contents of total phenoliccompounds in the transgenic plants were lower than those of the wild-type plants, and notsignificantly changed except in the treatment of prolonged low-temperature. However, the totalflavonoids contents of the transgenic plants were dramatically increased under prolongedtemperature stress. The DPPH scavenging activities of the transgenic plants were higher thanthose of the wild-type plants under temperature stress. Consequently, it was revealed thatoverexpressing OsHSP26 allow for P. alba to be tolerant to temperature stress.