Singh Richard R, Nobleza Neriza, Demeestere Kristof, Kyndt Tina
Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
Research Group Environmental Organic Chemistry and Technology (EnVOC), Department of Green Chemistry and Technology, Ghent University, Ghent, Belgium.
Front Plant Sci. 2020 Oct 22;11:591715. doi: 10.3389/fpls.2020.591715. eCollection 2020.
Ascorbate oxidase (AO) is an enzyme involved in catalyzing the oxidation of apoplastic ascorbic acid (AA) to dehydroascorbic acid (DHA). In this research, the potential of AO spraying to induce systemic resistance was demonstrated in the interaction between sugar beet root and cyst nematode and the mechanism was elucidated. Plant bioassays showed that roots of AO-sprayed plants were infested by a significantly lower number of females and cysts when compared with mock-sprayed control plants. Hormone measurements showed an elevated level of jasmonic acid (JA) salicylic acid (SA) and ethylene (ET) in the roots of AO-sprayed plants, with a dynamic temporal pattern of activation. Experiments with chemical inhibitors showed that AO-induced systemic resistance is partially dependent on the JA, ET and SA pathways. Biochemical analyses revealed a primed accumulation of hydrogen peroxide (HO), and phenylalanine ammonia lyase (PAL) activity in the roots of AO-sprayed plants upon infection by cyst nematodes. In conclusion, our data shows that AO works as an effective systemic defense priming agent in sugar beet against cyst nematode infection, through activation of multiple basal plant defense pathways.
抗坏血酸氧化酶（AO）是一种参与催化质外体抗坏血酸（AA）氧化为脱氢抗坏血酸（DHA）的酶。在本研究中，AO喷雾诱导系统抗性的潜力在甜菜根与孢囊线虫的相互作用中得到了证实，并阐明了其机制。植物生物测定表明，与模拟喷雾处理的对照植物相比，AO喷雾处理植物的根被侵染的雌虫和孢囊数量显著减少。激素测定表明，AO喷雾处理植物的根中茉莉酸（JA）、水杨酸（SA）和乙烯（ET）水平升高，且具有动态的激活时间模式。化学抑制剂实验表明，AO诱导的系统抗性部分依赖于JA、ET和SA途径。生化分析揭示，在被孢囊线虫侵染后，AO喷雾处理植物的根中过氧化氢（HO）和苯丙氨酸解氨酶（PAL）活性出现了预激发积累。总之，我们的数据表明，AO通过激活多种植物基础防御途径，作为一种有效的系统防御激发剂，在甜菜中抵御孢囊线虫感染。
