Ascorbate oxidase: The unexpected involvement of a %26apos;wasteful enzyme%26apos; in the symbioses with nitrogen-fixing bacteria and arbuscular mycorrhizal fungi

作者：Balestrini Raffaella; Ott Thomas; Guether Mike; Bonfante Paola; Udvardi Michael K; De Tullio Mario C^*

来源：Plant Physiology and Biochemistry, 2012, 59: 71-79.

DOI：10.1016/j.plaphy.2012.07.006

• Ascorbate
• Ascorbate oxidase
• Oxygen
• Plant-microorganism interaction
• Root nodules
• Arbuscular mycorrhizal fungi
• Signaling

Ascorbate oxidase (AO, EC 1.10.3.3) catalyzes the oxidation of ascorbate (AsA) to yield water. AO overexpressing plants are prone to ozone and salt stresses, whereas lower expression apparently confers resistance to unfavorable environmental conditions. Previous studies have suggested a role for AO as a regulator of oxygen content in photosynthetic tissues. For the first time we show here that the expression of a Lotus japonicus AO gene is induced in the symbiotic interaction with both nitrogen-fixing bacteria and arbuscular mycorrhizal (AM) fungi. In this framework, high AO expression is viewed as a possible strategy to down-regulate oxygen diffusion in root nodules, and a component of AM symbiosis. A general model of AO function in plants is discussed.

• 出版日期2012-10