Role of Vitamin B6 as an antioxidant during plant-microbe interactions

建议摘要-2500病原体侵袭后最快速的植物防御反应之一是所谓的氧化猝发，它构成了试图入侵的部位产生的活性氧物种(ROS)。维生素B6(VB6)是多种代谢酶的必需辅因子，是一种有效的抗氧化剂，在植物的发育过程和逆境反应中发挥重要作用。然而，对其在植物对土传病原菌侵染的抗病反应中的作用却知之甚少。杂草(Brachypodium disachyon，Bd)是牧草基因组学和基因发现的模式系统，越来越多地被用作谷类病害的模式植物。立枯丝核菌(Rhizoctonia solani AG-8)引起小麦和大麦丝核菌根腐病和出苗前倒伏病(又名赤斑病)，这两种病害是世界各地谷物产区的两种主要限产病害。所有已知的小麦和大麦品种，包括那些对锈病和其他病原菌具有抗性的品种，都对立枯丝核菌AG-8敏感，缺乏对丝核菌的控制是广泛采用直播的主要障碍。Brachypodium品系被土传植物病原菌R.solani AG-8侵染，并表现出与作物寄主(小麦)相似的症状。因此，本研究对青霉VB6增强系进行了研究。茄尼相互作用有望提高我们对抗病的认识，从而产生抗病品系。在本研究中，我们通过对Bd品系中VB6生物合成基因的功能分析，探讨了VB6在水稻纹枯病菌防御反应中的作用。该提案将深入了解VB6在植物对病原体的反应中的作用及其作为抗氧化剂的作用，并了解VB6在保护病原体免受氧化胁迫中的作用。方法：将建立高表达(OX)VB6基因的BD转基因系，并进行一系列实验，以提供证据，证明OX系中维生素B6含量的增加可以提高对氧化应激的耐受性，并且比WT系对立枯病菌感染或百草枯(ROS诱导剂)更不敏感。此外，我们还将探索转录组和代谢组水平的整个细胞过程是如何受到影响的，因为预期VB6基因增强或减少的BD株系的初级代谢将发生广泛变化。预期意义：在过量表达VB6编码基因的Bd植物中发现对纹枯病菌抗性的数量变异将有助于选择抗病品系。这一代作物结合了生物可利用的VB6维生素水平的提高和对真菌病原体引起的氧化应激的耐受性等更好的通用特征，是改善营养和粮食安全的宝贵工具。HQP培训：5名研究生和1名PDF将接受“组学”学科、生物信息学和植物-微生物相互作用方面的培训。O

Summary of ProSummary of Proposal-2500 One of the most rapid plant defense reactions after pathogen attack is the so-called oxidative burst, which constitutes the production of reactive oxygen species (ROS) at the site of attempted invasion. Vitamin B6 (VB6), an essential cofactor for numerous metabolic enzymes, is a potent antioxidant and plays important roles in developmental process and plant stress responses. However, little is known about its function in plant disease resistance response against soilborne pathogen infections. Brachypodium distachyon (Bd) is now established as the model system for grass genomics and gene discovery and is increasingly used as the model for cereal disease. Rhizoctonia solani AG-8 causes rhizoctonia root rot and pre-emergence damping-off (aka barepatch) of wheat and barely, two major yield-limiting diseases in cereal production regions worldwide. All known cultivars of wheat and barley, including those having resistance to rusts and other pathogens, are susceptible to R. solani AG-8 and lack of control of Rhizoctonia poses a major barrier to the widespread adoption of direct seeding. Brachypodium lines are infected by the soilborne plant pathogen R. solani AG-8, and develop similar symptoms to the crop host (wheat). Thus, the study of enhanced VB6 lines of Brachyodium-R. solani interactions holds promise to improve our understanding of disease resistance and hence generation of R. solani resistant lines. In the present proposal we explore the involvement of VB6 in defense response against the R. solani through functional analysis of VB6 biosynthetic genes in Bd lines. The proposal will provide insight into the effect of the VB6 on plant response to pathogens and its role as an antioxidant, and also to understand the role of VB6 in the protection of the pathogen against oxidative stress. Approach: Bd transgenic lines overexpressing (OX) VB6 genes followed by a series of experiments will be generated in order to provide evidence that enhanced vitamin B6 content in OX lines have increased tolerance to oxidative stress and are less susceptible than WT lines to R. solani infections or to paraquat (ROS inducer). Also, we will explore how whole-cellular processes at the transcriptome and metabolome levels are affected since broad changes of the primary metabolism of Bd lines with enhanced or reduced VB6 genes are anticipated. Expected significance: Finding quantitative variation in resistance to R. solani in Bd plants overexpressing VB6 encoding genes would allow selection of resistant lines. The generation of crops combining enhanced levels of bioavailable VB6 vitamers and better generic traits such as tolerance to oxidative stress caused by fungal pathogens represent a valuable tool to improve nutrition and food security. HQP training: 5 graduate students and a PDF will be trained in `omics' disciplines, bioinformatics and plant-microbe interactions. O