摘要
脱落酸(Abscisic Acid,ABA)是一种重要的植物激素,在种子和芽休眠、器官大小控制、植物衰老和死亡等发育过程中发挥作用,同时调控植物的生物与非生物胁迫。为快速、准确地测定植物体内ABA的含量,本研究开发了一种新型的ABA免疫传感器。通过在电极表面修饰羧基化石墨烯(GR-COOH)及海藻酸钠(Sodium Alginate,SA)来增加抗体的固定量,从而提高传感器的检测性能。对GR-COOH、SA、ABA抗体的浓度进行了优化,根据ABA抗体和抗原的结合导致电极阻抗发生变化的原理,实现了ABA的检测。传感器在10 pmol/L~1μmol/L范围内与ABA浓度呈线性关系,实测的检测下限为10 pmol/L,具有较好的稳定性和选择性。进一步以感染柑橘黄龙病的脐橙为研究对象,通过制备的基于GR-COOH-SA复合材料的ABA免疫传感器检测了黄龙病菌侵染下脐橙叶片中ABA的含量变化。结果表明,脐橙感染黄龙病后,叶片中ABA的含量增加,从而表明ABA在植物的抗病反应中发挥重要作用。进一步研究了ABA合成途径中关键酶的基因CitZEP表达量的变化,植株感病后基因表达量升高,传感器测得的ABA含量升高与传感器的检测结果相符,表明基于GR-COOH-SA复合材料的ABA免疫传感器具有较好的实用性。
Abscisic acid(ABA)is an important plant hormone,which can control seed and bud dormancy,organ size control,senescence and death,and participate in both biological and abiotic stress,inhibit plant growth,and participate in plant disease resistance.In order to determine the content of ABA in plants quickly and accurately,a new type of ABA immunosensor was developed.To improve the detection performance of the sensor,the detection performance of the sensor was increased by modifying GR-COOH and SA on the electrode surface.The concentration of GR-COOH,SA,and ABA-Antibody were optimized,the optimal conditions for the three materials were 1.5 mg/ml,1.25 mg/ml and 0.5 mg/ml.The immunosensor was constructed based on the electrode impedance changes(△Z)due to the binding reaction of ABA antibody and antigen.It was found that the sensor showed linear relationship with ABA in the response range of 10 pmol/L~1μmol/L,R2was 0.99927,and the detection limit was about 10 pmol/L.The sensor also had good selectivity and stability.Using the electrochemical immunosensor,the content of ABA in navel orange leaf that have been successfully inoculated with citrus Huanglongbing by PCR was determined,and healthy plants were used as control.The test results showed that the impedance changes(△Z)of healthy leaves and diseased leaves were 72 and 823,respectively,which indicated that the level of ABA in the infected plants increased significantly.The sensor provides a tool for the detection of plant hormone levels under disease stress.The results showed that the content of ABA increased in the leaves of navel orange infected by citrus Huanglongbing,which indicated that ABA played an important role in plant disease resistance.Furthermore,the changes of gene expression of key enzymes CitZEP in ABA synthesis pathway were studied,The results showed that the expression of CitZEP increased in plants infected with Huanglongbing disease,and the results were consistent with the detection results of the sensor,which indicated that the sensor had good practicability.
作者
董宏图
周思蒙
王清涛
王成
罗斌
李爱学
DONG Hongtu;ZHOU Simeng;WANG Qingtao;WANG Cheng;LUO Bin;LI Aixue(Research Center of Information Technology,Beijing Academy of Agriculture and Foreatry Sciences,Beijing 100097,China;College of Landscape and Ecological Engineering,Hebei University of Engineering,Handan 056038,China)
基金
国家自然科学基金项目(21974012)。