Li Zhou, Jing Wen, Peng Yan, Zhang Xin Quan, Ma Xiao, Huang Lin Kai, Yan Yan-Hong
Department of Grassland Science, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, China.
PLoS One. 2015 Apr 2;10(3):e0120708. doi: 10.1371/journal.pone.0120708. eCollection 2015.
The objective of this research was to analyse whether ameliorating drought stress through exogenously applied spermine (Spm) was related to carbohydrate metabolism, dehydrins accumulation and the transcription of genes encoding dehydrins in two white clovers (drought-susceptible cv. 'Ladino' and drought-resistant cv. 'Haifa') under controlled drying conditions for 10 days. The results show that the application of Spm effectively alleviates negative effects caused by drought stress in both cultivars. Exogenous Spm led to accumulation of more water-soluble carbohydrates (WSC), sucrose, fructose and sorbitol in both cultivars under drought stress, and also significantly elevated glucose content in leaves of drought-resistant cv. 'Haifa', but had no effect on drought-susceptible cv. 'Ladino'. Accordingly, the key enzyme activities of sucrose and sorbitol metabolism changed along with the application of Spm under drought stress. Spm induced a significant increase in sucrose phosphate synthase (SPS) or sorbitol dehydrogenase (SDH) activity, but decrease in sucrose synthetase (SS) activity when two cultivars were subjected to drought. In addition, the improved accumulation of dehydrins induced by exogenous Spm coincided with three genes expression which was responsible for dehydrins synthesis. But Spm-induced transcript level of dehydrin genes increased earlier in cv. 'Ladino' than that in cv. 'Haifa'. Thus, these results suggest that ameliorating drought stress through exogenously applied Spm may be associated with increased carbohydrate accumulation and dehydrins synthesis. There are differences between drought-susceptible and -resistant white clover cultivars related to Spm regulation of WSC metabolism and dehydrins expression.
本研究的目的是分析在控制干燥条件下持续10天，通过外源施用精胺（Spm）改善干旱胁迫是否与两种白三叶（干旱敏感品种‘拉迪诺’和抗旱品种‘海法’）的碳水化合物代谢、脱水素积累以及编码脱水素的基因转录有关。结果表明，施用Spm可有效减轻两个品种干旱胁迫造成的负面影响。外源Spm使两个品种在干旱胁迫下积累了更多的水溶性碳水化合物（WSC）、蔗糖、果糖和山梨醇，同时显著提高了抗旱品种‘海法’叶片中的葡萄糖含量，但对干旱敏感品种‘拉迪诺’没有影响。因此，在干旱胁迫下，蔗糖和山梨醇代谢的关键酶活性随Spm的施用而变化。当两个品种遭受干旱时，Spm使蔗糖磷酸合酶（SPS）或山梨醇脱氢酶（SDH）活性显著增加，但使蔗糖合成酶（SS）活性降低。此外，外源Spm诱导的脱水素积累增加与负责脱水素合成的三个基因的表达一致。但Spm诱导的脱水素基因转录水平在‘拉迪诺’品种中比在‘海法’品种中更早升高。因此，这些结果表明，通过外源施用Spm改善干旱胁迫可能与碳水化合物积累增加和脱水素合成有关。干旱敏感和抗旱白三叶品种在Spm对WSC代谢和脱水素表达的调控方面存在差异。
