Thermotolerance of transgenic tobacco with altered expression of mitochondrial small heat shock proteins
Description
[Objectives]
Plants respond to heat stress by repressing the expression of mRNAs for most normal proteins that induce the synthesis of heat shock proteins (HSPs). Heat-stressed plant cells accumulate mitochondria-located small heat shock proteins (MT-sHSP) and the accumulation is synchronized with the thermotolerance of mitochondria. Under heat stress, mitochondrial metabolic pathways breakdown and function abnormally, thus diminishing cell viability. While Division researchers have already shown that tomato MT-sHSP has a molecular chaperone function in vitro, the goal of this study was to clarify the role of MT-sHSP in vivo during heat-shock response using MT-sHSP transgenic tobacco.
[Results]
Researchers introduced the tomato MT-sHSP gene into tobacco plants (Nicotiana tabacum L. cv. SR1) with sense and antisense constructs under the control of the CaMV 35S promoter, and then examined the thermotolerance of the seedlings. Sense plants overexpressed MT-sHSP even under normal growth temperatures, while antisense transformants accumulated less MT-sHSP than control plants under heat stressed conditions (Fig. 1). Irrespective of gene orientation, sense or antisense, transgenic plants exhibited a normal morphology and growth rate in the vegetative growth stage (Fig. 2). Thus, MT-sHSP does not have a pleiotropic effect on vegetative growth under normal conditions.
When the 4-week-old seedlings (T2 progeny) were exposed to sudden high temperature stress for two hours, sense plants exhibited thermotolerance and survived at 48°C, whereas control tobacco did not survive. On the other hand, antisense plants were susceptible to stress at 46°C, whereas control tobacco can survive under such conditions (Fig. 3). These results indicate that MT-sHSP plays a pivotal role in heat-shock response.
Figure, table
- Affiliation
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Japan International Research Center for Agricultural Sciences Okinawa Subtropical Station
- Classification
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Technical A
- Term of research
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FY2002 (FY1998-2002)
- Responsible researcher
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SHONO Mariko ( Okinawa Subtropical Station )
SANMIYA Kazutsuka ( Bio-oriented Technology Research Advancement Institution )
LIU Jian ( Shandong Teacher University, China )
SINGH Ishwar ( Indian Institute of Sugarcane Research, India )
DIN Jaral Ud ( Land Resources Research Institute, Pakistan )
SUZUKI Katsumi ( Okinawa Subtropical Station )
TSUKAGUCHI Tadashi ( Bio-oriented Technology Research Advancement Institution )
EGAWA Yoshinobu ( Okinawa Subtropical Station )
- ほか
- Publication, etc.
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Liu, J. and Shono, M. (1999) Characterization of mitochondria-located small heat shock protein from tomato (Lycopersicon esculentum). Plant and Cell Physiology, 40, 1297–1304.
- Japanese PDF
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2002_24_A3_ja.pdf696.67 KB
- English PDF
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2002_24_A4_en.pdf61.6 KB