Glycinebetaine enhances the tolerance of tomato plants to high temperature during germination of seeds and growth of seedlings
Shufen Li1, Feng Li1, Jianwei Wang1, Wen Zhang1, Qingwei Meng1, Tony HH Chen2, Norio Murata3 and Xinghong Yang1*
1College of Life Science, State Key Laboratory of Crop Biology, Shandong Key Laboratory of Crop Biology, Shandong Agricultural University, Taian 271018, People’s Republic of China.
2Department of Horticulture, ALS 4017, Oregon State University, Corvallis, OR 97331, USA.
3National Institute for Basic Biology, Okazaki 444-8585, Japan .
*Corresponding author: Tel: (+86538 8246167); E-mail address: firstname.lastname@example.org
Tomato (Lycopersicon esculentum cv. ‘Moneymaker’) was transformed with a codA gene, from Arthrobacter globiformis, for choline oxidase that had been modified to allow targeting to both chloroplasts and the cytosol. After incubation at temperatures from 25 oC to 55 oC for 90 min during imbibition, codA-transgenic seeds germinated faster and at higher frequency than wild-type seeds. After the exposure of imbibed seeds to 40o/30 oC (12 h/12 h) or 34o/34 oC (16 h/8 h), transgenic seeds germinated faster and developed more vigorous seedlings than wild-type seeds. We compared the expression of genes for a mitochondrial small heat-shock protein (MT-sHSP), heat-shock protein 70 (HSP70), and heat shock cognate 70 (HSC70) between wild-type and transgenic seeds after heat stress at 34 oC. Levels of expression of all three genes were higher in transgenic seeds than in wild-type seeds during heat stress, and the accumulation of HSP70 was more prominent in codA-transgenic seeds than in wild-type seeds. Our results suggest that GB, either applied exogenously or accumulated in vivo in codA-transgenic seeds, enhanced the expression of heat-shock genes and improved the tolerance to high temperature of tomato seeds during germination.
Key-words: Glycinebetaine; heat-shock protein; high temperature; seed germination; tomato