Overexpression of NtHAL3 genes confers increased levels of proline biosynthesis and the enhancement of salt tolerance in cultured tobacco cells.
نویسندگان
چکیده
The Hal3 protein of Saccharomyces cerevisiae inhibits the activity of PPZ1 type-1 protein phosphatases and functions as a regulator of salt tolerance and cell cycle control. In plants, two HAL3 homologue genes in Arabidopsis thaliana, AtHAL3a and AtHAl3b, have been isolated and the function of AtHAL3a has been investigated through the use of transgenic plants. Expressions of both AtHAL3 genes are induced by salt stress. AtHAL3a overexpressing transgenic plants exhibit improved salt and sorbitol tolerance. In vitro studies have demonstrated that AtHAL3 protein possessed 4'-phosphopantothenoylcysteine decarboxylase activity. This result suggests that the molecular function of plant HAL3 genes is different from that of yeast HAL3. To understand the function of plant HAL3 genes in salt tolerance more clearly, three tobacco HAL3 genes, NtHAL3a, NtHAL3b, and NtHAL3c, from Nicotiana tabacum were identified. NtHAL3 genes were constitutively expressed in all organs and under all conditions of stress examined. Overexpression of NtHAL3a improved salt, osmotic, and lithium tolerance in cultured tobacco cells. NtHAL3 genes could complement the temperature-sensitive mutation in the E. coli dfp gene encoding 4'-phosphopantothenoyl-cysteine decarboxylase in the coenzyme A biosynthetic pathway. Cells overexpressing NtHAL3a had an increased intracellular ratio of proline. Taken together, these results suggest that NtHAL3 proteins are involved in the coenzyme A biosynthetic pathway in tobacco cells.
منابع مشابه
Stereo-Specific Transcript Regulation of the Polyamine Biosynthesis Genes by Enantiomers of Ornithine in Tobacco Cell Culture
Background: Ornithine (Orn) plays an essential role in the metabolism of plant cells through incorporation in polyamines biosynthesis, the urea cycle and nitrogen metabolism. Physiological response of the plant cells to its two enantiomers have not been widely investigated yet.Objectives: This study aimed to evaluate effect of ornithine enantiomers on exp...
متن کاملEffects of exogenous ornithine enantiomers on tobacco cells under salinity conditions
Ornithine is a non-proteinogenic amino acid, which plays an essential role in the metabolism of plants. Regard to the chirality of the molecule, physiological response of the plant cells to its two enantiomers have not been widely investigated yet. In the present study, suspension-cultured tobacco cells were treated with 1 mM of D- and Lenantiomers of ornithine in normal conditions as well as u...
متن کاملInfluence of Si Supplementation on Growth and Some Physiological and Biochemical Parameters in Salt-Stressed Tobacco (Nicotiana rustica L.) Plants
Tobacco is a salt-sensitive glycophyte crop species. In this work effect of silicone (Si) supplementation (1 mM as Na2SiO3) was studied in Nicotiana rustica L. cv. Basmas grown hydroponically in growth chamber under control, low (25 mM) and high (75 mM) NaCl concentration for two weeks. Dry matter production of leaves was depressed by salinity level as low as 25 mM and higher salt concentration...
متن کاملResponses of Transgenic Tobacco (Nicotiana plambaginifolia) Over-Expressing P5CS Gene Underin vitroSalt Stress
Salinity is a major limiting factor for plant growth and development. To evaluate the impact of P5CS gene expression under in vitro salt stress condition, transgenic tobacco (Nicotiana plumbaginifolia) carrying P5CS gene and non-transgenic plants were treated with 0, 100, 150, 200 or 250 mM NaCl for 28 days. Proline content, lipid peroxidation and the activity of some antioxidant enzymes after ...
متن کاملDifferential Changes of Proline Content and Activities of Antioxidant Enzymes Results in Varied Salt-Tolerance in Canola Genotypes
Saline soils and saline irrigation waters present potential hazards to canola production. Therefore, in this study in order to find indicators for salt tolerance, the changes of proline content and the activities of antioxidant enzymes were investigated in two canola genotypes (H308, H420) under various salt concentrations (0, 50, 100, 150 and 200 mM). Results showed that compared to the contr...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Journal of experimental botany
دوره 55 396 شماره
صفحات -
تاریخ انتشار 2004