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

ProSummary of Proposal-2500病原体攻击后最快速的植物防御反应之一是所谓的氧化爆发，它构成了在试图入侵的部位产生活性氧（ROS）。维生素B6（VB 6）是多种代谢酶的重要辅助因子，是一种强有力的抗氧化剂，在植物发育过程和胁迫反应中起着重要作用。然而，关于它在植物抗土传病原菌侵染中的作用却知之甚少。二穗短柄草（Brachypodium distachyon，Bd）是禾本科植物基因组学和基因发现的模式系统，也越来越多地被用作禾本科植物病害的模式系统。立枯丝核菌（Rhizoctonia solani AG-8）引起小麦和大麦的立枯丝核菌根腐病和苗前立枯病（又称裸斑病），这是世界范围内谷物生产地区的两种主要产量限制性病害。所有已知的小麦和大麦品种，包括那些对锈病和其他病原体具有抗性的品种，都对R. solani AG-8和缺乏对丝核菌的控制构成了直接播种广泛采用的主要障碍。短柄草品系被土传植物病原菌R. solani AG-8，并发展出与作物宿主（小麦）相似的症状。因此，对Brachyodium-R. solani相互作用有望提高我们对抗病性的理解，从而提高R.抗茄病品系在目前的建议中，我们探讨了VB 6参与防御反应对R。通过对Bd株系中VB 6生物合成基因的功能分析，该提案将深入了解VB 6对植物对病原体的反应及其作为抗氧化剂的作用，并了解VB 6在保护病原体免受氧化胁迫中的作用。方法：将产生过表达（OX）VB 6基因的Bd转基因系，随后进行一系列实验，以提供证据证明OX系中维生素B6含量增加具有增加的对氧化应激的耐受性，并且比WT系对R. solani感染或百草枯（ROS诱导剂）。此外，我们将探讨如何在转录组和代谢组水平的全细胞过程的影响，因为广泛的变化，增强或减少VB 6基因的Bd线的初级代谢的预期。预期意义：发现对R.过量表达VB 6编码基因的Bd植物中的solani将允许选择抗性品系。结合生物可利用的VB 6维生素水平提高和更好的遗传性状，如对真菌病原体引起的氧化应激的耐受性的作物的产生代表了改善营养和粮食安全的有价值的工具。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