百人博士张文浩发现植物抗冻基因

　　

生物通报道，来自中国科学院植物研究所张文浩研究员在《Plant Physiology》上发表植物抗冻研究成果文章Nitric Reductase-Dependent Nitric Oxide Production Is Involved in Cold Acclimation and Freezing Tolerance in Arabidopsis，解析植物低温环境下的抗冻机制。

 

生长在温带的植物能通过感受零上的低温改变其生理生化过程，提高其抗冻性。许多信号分子（ABA, BR等）参与植物低温驯化过程。

 

张文浩研究组通过植物生理学、分子生物学和药理学的段，利用拟南芥野生型和一氧化氮（NO）合成相关突变体，研究了信号分子NO在植物低温驯化和抗冻中的作用。

 

 

图：低温驯化通过促进NIA1基因的表达，诱导硝酸还原酶介导的植物内源一氧化氮合成，增加脯氨酸的累积，提高植物的抗冻能力。

 

研究发现，低温驯化上调编码硝酸还原酶（NR）的NIA1基因表达，导致NR依赖性NO合成的增加。NO通过增加脯氨酸（Pro）的合成和抑制Pro的降解，促进Pro积累，从而提高植物的抗冻。该发现对认识植物一氧化氮功能和揭示植物低温驯化调控机制具有重要的理论意义。

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Nitric Reductase-Dependent Nitric Oxide Production Is Involved in Cold Acclimation and Freezing Tolerance in Arabidopsis

Nitric oxide (NO) is an important signaling molecule involved in many physiological processes in plants. We evaluated the role of NO in cold acclimation and freezing tolerance using Arabidopsis (Arabidopsis thaliana) wild type and mutants nia1nia2 (for nitrate reductase [NR]-defective double mutant) and Atnoa1/rif1 (for nitric oxide associated1/resistant to inhibition by fosmidomycin1) that exhibit defects in NR and reduced NO production, respectively. Cold acclimation induced an increase in endogenous NO production in wild-type and Atnoa1/rif1 leaves, while endogenous NO level in nia1nia2 leaves was lower than in wild-type ones and was little changed during cold acclimation. Cold acclimation stimulated NR activity and induced up-regulation of NIA1 gene expression. In contrast, cold acclimation reduced the quantity of NOA1/RIF1 protein and inhibited NO synthase (NOS) activity. These results indicate that up-regulation of NR-dependent NO synthesis underpins cold acclimation-induced NO production. Seedlings of nia1nia2 were less tolerant to freezing than wild-type plants. Pharmacological studies using NR inhibitor, NO scavenger, and NO donor showed that NR-dependent NO level was positively correlated with freezing tolerance. Furthermore, cold acclimation up- and down-regulated expression of P5CS1 and ProDH genes, respectively, resulting in enhanced accumulation of proline (Pro) in wild-type plants. The stimulation of Pro accumulation by cold acclimation was reduced by NR inhibitor and NO scavenger, while Pro accumulation by cold acclimation was not affected by the NOS inhibitor. In contrast to wild-type plants, cold acclimation up-regulated ProDH gene expression in nia1nia2 plants, leading to less accumulation in nia1nia2 plants than in wild-type plants. These findings demonstrate that NR-dependent NO production plays an important role in cold acclimation-induced increase in freezing tolerance by modulating Pro accumulation in Arabidopsis.

 

张文浩

博士，植物水分养分生物学研究组首席研究员，博士生导师。1986年毕业于内蒙古农业大学草原系，同年考入中国农科院1986年底被选为国家教委出国留学预备生， 1994年获得澳大利亚Flinders大学生物学博士学位，2004年作为海外知名学者加入到植物所，成立了植物养分水分生物学创新研究组。曾主持和参加了多项澳大利亚研究委员会（Australian Research Council）的项目，在水分跨膜运输、韧皮部卸出机理及调控、作物铝毒害和抗铝毒害、作物对低磷适应、植物钙信号转导等研究领域做了一系列的原创性工作。 以第一作者和通讯作者身份在Plant Journal，Plant Physiology，Plant Cell & Environment, Planta等该领域权威刊物上发表论文十余篇。 同时还定期为《Plant Physiology》, 《Plant Cell & Environment》,《Journal of Experimental Botany》,《Physiologia Plantarum》 等国际杂志审稿，还被澳大利亚研究委员会（Australian Research Council）聘请为国际评审专家，评议该委员会的课题申请。2004年入选中科院“****”。