欧亚国际

最近，来自欧洲的科学家利用WIWAM XY（Pathoviewer）高通量植物表型成像平台发表了题为Induced Resistance by Ascorbate Oxidation Involves Potentiating of the Phenylpropanoid Pathway and Improved Rice Tolerance to Parasitic Nematodes，文章发表于知名期刊Frontiers in Plant Science上。

SMO构建WIWAM XY（Pathoviewer）高通量植物表型成像平台

WIWAM植物表型成像系统由比利时SMO公司与GHent大学VIB研究所研制生产，整合了LED植物只能培养、自动化控制系统、叶绿素荧光成像测量分析、植物热成像分析、植物近红外成像分析、植物高光谱分析、植物多光谱分析、植物CT断层扫描分析、自动条码识别管理、RGB真3D成像等多项先进技术，以优化的方式实现大量植物样品以优化的方式实现大量植物样品——从拟南芥、水稻、玉米到各种其它植物的生理生态与形态结构成像分析，用于高通量植物表型成像分析测量、植物胁迫响应成像分析测量、植物生长分析测量、生态毒理学研究、性状识别及植物生理生态分析研究等。

PathoViewer是一款高通量植物表型成像平台（属于WIWAM XY系列），使用了高分辨率图像在可控条件下对植物进行表型成像。该系统配备有6MP-16 bit的相机系统以及各种光学滤波轮，有广泛用途，例如测量叶绿素荧光、红色荧光蛋白、绿色荧光蛋白、自荧光、RGB改进花青素反射指数以及叶绿素指数等。系统为自动系统，用于测量植物或植物部分的生物或非生物胁迫。

Pathoviewer 特点

Pathoviewer组合了RGB, 叶绿素荧光、花青素、NIR和GFP/RFP图像处理，对生物和非生物胁迫的影响进行成像。这些相机也可为研究人员采集植物科学相关信息，另外还可对表型特征可视化。下文将对测量的最重要参数进行讨论。

Pathoviewer能测量的最重要参数是Fv/FM值。该值通过叶绿素荧光获取，是指示测量植物光合性能的参数。荧光可用于测量PSII光合作用中的多种参数如线性电子流，CO2同化以及变化。 

抗坏血酸氧化诱导的抗性包括增强苯丙烷途径和提高水稻对寄生线虫的耐受性

随着人们对生态意识的提高，科学家们一直在探索减少使用化学杀虫剂来控制病虫害的新策略。触发植物内在防御系统是减少线虫等病原生物产量损失的有效策略之一。抗坏血酸氧化酶（AO）通过抗坏血酸氧化过程调节质外体抗坏血酸/脱氢抗坏血酸（DHA）的比例，在植物防御中发挥重要作用。抗坏血酸氧化可诱导水稻对寄生根结线虫（RKN）的系统抗性。本研究中，我们试图评估AO或DHA是否诱导对RKN M的耐药性（IR）。Graminicola涉及苯丙烷途径的激活，以及该IR表型是否对胁迫和非胁迫条件下水稻幼苗的生长具有潜在影响。我们的结果表明，AO/DHA-IR对这些寄生线虫的抗性依赖于苯丙氨酸解氨酶（PAL）的激活。然而，应用还原抗坏血酸（AA）并没有引起这种反应。通过qRT PCR进行的基因表达分析表明，OsPAL2和OsPAL4在喷洒AO/DHA的线虫感染根中高度表达，PAL活性测定证实，喷洒AO/DHA可触发植物在线虫感染时激活该酶。AO/DHA-IR对喷洒化学PAL抑制剂的植物无效，证实AO/DHA诱导的抗性取决于PAL活性。在AO/DHA喷施的植物中，植物生长的改善和线虫感染的降低被发现与枝叶的叶绿素荧光（Fv/Fm）、叶绿素指数（ChlIdx）和改良花青素反射指数的增加相关，证明其是良好的线虫侵染的地上指示参数。详细的生长分析证实，在线虫感染的条件下，AO/DHA处理的植物生长得到改善。综上所述，我们的结果表明，抗坏血酸氧化增强了基于苯丙烷的线虫感染反应，并导致处理后的水稻植株表现出耐性表型。

Induced Resistance by Ascorbate Oxidation Involves Potentiating of the Phenylpropanoid Pathway and Improved Rice Tolerance to Parasitic Nematodes 

ichard Raj Singh1,Jessil Ann Pajar1†,Kris Audenaert2 and Tina Kyndt1*

1Department of Biotechnology, Faculty of Biosescience Engineering, Ghent University, Ghent, Belgium

2Department of Plants and Crops, Ghent University, Ghent, Belgium

Anticipating an increased ecological awareness, scientists have been exploring new strategies to reduce the use of chemical pesticides to control pests and diseases. Triggering the intrinsic plant defense system is one of the promising strategies to reduce yield loss by pathogenic organisms, such as nematodes. Ascorbate oxidase (AO) enzyme plays an important role in plant defense by regulating the apoplastic ascorbate/dehydroascorbate (DHA) ratio via the ascorbate oxidation process. Ascorbate oxidation is known to induce systemic resistance in rice against parasitic root-knot nematodes (RKN). Here, we sought to evalsuate if AO- or DHA-induced resistance (IR) against RKN M. graminicola involves activation of the phenylpropanoid pathway and whether this IR phenotype has potential effects on growth of rice seedlings under stressed and unstressed conditions. Our results show that AO/DHA-IR against these parasitic nematodes is dependent on activation of phenylalanine ammonia lyase (PAL). However, application of reduced ascorbic acid (AA) did not induce this response. Gene expression analysis via qRT-PCR showed that OsPAL2 and OsPAL4 are highly expressed in AO/DHA-sprayed nematode-infected roots and PAL-activity measurements confirmed that AO/DHA spraying triggers the plants for primed activation of this enzyme upon nematode infection. AO/DHA-IR is not effective in plants sprayed with a chemical PAL inhibitor confirming that AO/DHA-induced resistance is dependent on PAL activity. Improved plant growth and low nematode infection in AO/DHA-sprayed plants was found to be correlated with an increase in shoot chlorophyll fluorescence (Fv/Fm), chlorophyll index (ChlIdx), and modified anthocyanin reflection index which were proven to be good above-ground parameters for nematode infestation. A detailed growth analysis confirmed the improved growth of AO/DHA-treated plants under nematode-infected conditions. Taken together, our results indicate that ascorbate oxidation enhances the phenylpropanoid-based response to nematode infection and leads to a tolerance phenotype in treated rice plants.