Functional Plant Biology Section, Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India.
Mol Biol Rep. 2012 Oct;39(10):9563-72. doi: 10.1007/s11033-012-1821-7. Epub 2012 Jun 28.
Seed priming is a well known pre-germination strategy that improves seed performance. However, biochemical and molecular mechanisms underlying priming mediated stress tolerance are little understood. Here, we report results of the study on growth, physiological characteristics and expression of stress responsive genes in salt primed sugarcane cv. Co 86032 plants in response to salt (NaCl, 150 mM) or iso-osmotic (-0.7 MPa) polyethylene glycol-PEG 8000 (20 % w/v) stress exposure for 15 days. Variable growth, osmolyte accumulation and antioxidant capacity was revealed among the primed and non-primed plants. The primed plants showed better tolerance to the salt or PEG stress, as revealed by better growth and lower membrane damage, through better antioxidant capacity as compared to the respective non-primed controls. Further, steady state transcript expression analysis revealed up regulation of sodium proton antiporter (NHX) while, down regulation of sucrose transporter (SUT1), delta ( 1 )-pyrolline-5-carboxylate synthetase (P5CS) and proline dehydrogenase (PDH) in primed plants on exposure to the stress as compared to the non-primed plants. Transcript abundance of catalase (CAT2) decreased by about 25 % in leaves of non-primed stressed plants, however, the expression was maintained in leaves of the stressed primed plants to that of non-stressed controls. Thus, the results indicated priming mediated salt and PEG stress tolerance through altered gene expression leading to improved antioxidant capacity in sugarcane.
种子引发是一种众所周知的预发芽策略，可提高种子性能。然而，引发介导的胁迫耐受性的生化和分子机制还知之甚少。在这里，我们报告了对盐（NaCl，150mM）或等渗（-0.7MPa）聚乙二醇-PEG8000（20％w/v）胁迫暴露15天后，盐引发甘蔗品种 Co86032 植物生长、生理特性和应激响应基因表达的研究结果。在引发和未引发的植物之间揭示了可变的生长、渗透物积累和抗氧化能力。与各自的未引发对照相比，引发的植物通过更好的抗氧化能力表现出对盐或 PEG 胁迫更好的耐受性，表现为更好的生长和更低的膜损伤。此外，稳态转录表达分析显示，在暴露于胁迫时，钠离子-质子反向转运蛋白（NHX）上调，而蔗糖转运蛋白（SUT1）、delta（1）-吡咯啉-5-羧酸合成酶（P5CS）和脯氨酸脱氢酶（PDH）下调在引发的植物中，而非引发的植物。未引发胁迫植物叶片中的过氧化氢酶（CAT2）表达量下降了约 25％，而胁迫引发植物叶片中的表达量保持在非胁迫对照水平。因此，结果表明，通过改变基因表达，引发介导了甘蔗的耐盐和耐 PEG 胁迫，从而提高了抗氧化能力。
