Correa-Aragunde Natalia, Lombardo Cristina, Lamattina Lorenzo
Instituto de Investigaciones Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata. CC 1245, 7600 Mar del Plata, Argentina.
Departamento de Biología, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata. CC 1245, 7600 Mar del Plata, Argentina.
New Phytol. 2008 Jul;179(2):386-396. doi: 10.1111/j.1469-8137.2008.02466.x.
Nitric oxide (NO) is a bioactive molecule involved in several growth and developmental processes in plants. These processes are mostly characterized by changes in primary and secondary metabolism. Here, the effect of NO on cellulose synthesis in tomato (Solanum lycopersicum) roots was studied. The phenotype of roots, cellulose content, the incorporation of 14C-glucose into cellulosic fraction and the expression of tomato cellulose synthase (CESA) transcripts in roots treated with the NO donor sodium nitroprusside (SNP) were analysed. Nitric oxide affected cellulose content in roots in a dose dependent manner. Low concentrations of SNP (pmoles of NO) increased cellulose content in roots while higher concentrations of SNP (nmoles of NO) had the opposite effect. This result correlated with assays of 14C-glucose incorporation into cellulose in roots. The effect of NO on 14C-glucose incorporation into cellulose was transient and reversible. Microscopic analysis of roots suggested that NO affected primary cell wall cellulose synthesis. Three tomato cellulose synthase (SICESA) transcripts were identified. Reverse transcriptase polymerase chain reaction experiments were carried out and indicated that SICESA1 and SICESA3 levels were affected by high NO concentrations. Together, these results support the hypothesis that variations in NO levels influence cellulose synthesis and content in roots.
一氧化氮（NO）是一种生物活性分子，参与植物的多种生长和发育过程。这些过程大多以初生和次生代谢的变化为特征。在此，研究了NO对番茄（Solanum lycopersicum）根系纤维素合成的影响。分析了用NO供体硝普钠（SNP）处理的根系的表型、纤维素含量、14C-葡萄糖掺入纤维素部分的情况以及番茄纤维素合酶（CESA）转录本在根系中的表达。一氧化氮以剂量依赖的方式影响根系中的纤维素含量。低浓度的SNP（皮摩尔级的NO）增加了根系中的纤维素含量，而高浓度的SNP（纳摩尔级的NO）则产生相反的效果。这一结果与根系中14C-葡萄糖掺入纤维素的测定结果相关。NO对14C-葡萄糖掺入纤维素的影响是短暂且可逆的。根系的显微镜分析表明，NO影响初生细胞壁纤维素的合成。鉴定出了三种番茄纤维素合酶（SICESA）转录本。进行了逆转录聚合酶链反应实验，结果表明高浓度的NO会影响SICESA1和SICESA3的水平。总之，这些结果支持了以下假设：NO水平的变化会影响根系中纤维素的合成和含量。
