부산대학교 도서관

Acquired thermotolerance in plants refers to the ability to cope with lethal high temperatures and it reflects an actual tolerance mechanism that occurs naturally in plants. Tomato ( Solanum lycopersicum syn. Lycopersicon esculentum L.) is sensitive to high temperature at all stages of its growth and development. Considering the important role of the heat shock protein gene (s HSP24.4 gene) in imparting tolerance to high temperature stress in the cells and tissues, we isolated small HSP24.4 ( MasHSP24.4) cDNA from wild banana ( Musa accuminata) and introduced it into the cultivated tomato cv. PKM1 by using Agrobacterium tumefaciens-mediated genetic transformation. Stable integration and expression of the transgene in the tomato genome was demonstrated by Southern, Northern and Western blot analyses. There was no adverse effect of transgene expression on overall growth and development of the transgenic plants. The genetic analysis of the transgenic T2 lines showed that the transgene segregated in a Mendelian ratio. We compared the survival of T2 transgenic lines compared to the control plants after exposure to different levels of high temperature. The gene MasHSP24.4 was expressed in root, shoot and stem tissues under 45 °C treatment and conferred tolerance to high-temperature stress as shown by increased seed germination, healthy vegetative growth and normal fruit and seed setting. The transgenic tomato plants showed significantly better growth performance in the recovery phase following the stress. This thermotolerance appeared to be solely due to overexpression of the s HSP24.4 gene. Thus, the transgenic tomato plants developed during the present investigations can be grown at high temperatures. [ABSTRACT FROM AUTHOR]