Exploiting the growth promotion and induced resistance properties of Trichoderma hamatum for improved crop productivity.

到2050年，全球人口预计将达到90亿，全球农业将面临不可持续的需求，以满足未来的粮食需求。传统上依赖于植物育种和能源密集型农业的作物产量的提高不太可能满足这些需求，因此，以前被认为不适合农业的边际土地将需要开垦。这些土地中的大部分将具有次优肥力和贫瘠的土壤，需要投入大量的合成化肥来支持可持续的作物生产。然而，化肥价格的大幅上涨意味着许多农民，特别是发展中国家的农民，负担不起这种管理做法。化肥的财政负担螺旋式上升，加上公众对合成化学添加剂对环境和健康的影响日益焦虑，这意味着迫切需要研究可持续作物生产的替代战略。木霉菌株产生多种次生代谢物和分泌蛋白质。研究表明，木霉菌能够激活广谱免疫，缓解盐碱、干旱等多种非生物胁迫，提高光合作用效率，增强养分吸收，显著提高作物氮素利用效率。这些重要的属性都有助于增强植物的生长特性，通常在接种后表现得很明显。许多木霉菌株具有促进生长、增强对非生物胁迫的耐受性和广谱增强系统免疫力等积极的农艺特性，这些特性是引人注目和独特的。要利用木霉激活的信号网络来建立这些对农业有益的性状，需要了解生物活性诱导分子和这些激活剂所针对的信号网络。基因组和分析技术的快速发展意味着，现在是开发木霉等土壤微生物惊人的化学多样性的好时机，目的是改善一系列农学上重要植物物种的PGP和ISR。埃克塞特进行的研究已经确定了一种新的自然产生的根际真菌木霉(Trichoderma Hamatum)菌株(GD12)，该菌株可以提高作物产量，并在没有昂贵的化肥和破坏环境的农用化学品的情况下广泛增强对病原体的免疫力。目前，植物促进生长和增强系统抗性现象的机制尚不清楚，这一建议为解决诱导生物活性的分子基础和这些生物活性靶向的植物反应途径奠定了基础。这些综合知识对于考虑将木霉PGP和ISR转化到农业领域是重要的，也是必要的。这一多学科的研究计划将结合遗传学、基因组学和代谢组学来解开木霉PGP/ISR生物活性物质，捕捉由生物活性物质诱导的植物转录重编程，并确定PGP、ISR信号网络的关键组成部分。我们将使用比较转录组学来研究受木霉菌感染激活的拟南芥和水稻中的信号通路。结合在植物激素信号转导中受损的木霉和拟南芥突变株系，我们将确定与PGP和ISR有关的候选信号成分/途径。我们将利用液-质联用法进行代谢谱比较，以表征生物活性并测试其在不同植物上的药效，以开发新的天然农用化学品。

With the human population projected to reach 9 billion by the year 2050, unsustainable demands will be placed on global agriculture to meet future food requirements. Improvements in crops yields that have traditionally relied on plant breeding and energy intensive agriculture are unlikely to meet these needs and therefore marginal land, previously considered unsuitable for agriculture, will need to be brought into cultivation. Much of this land will have sub-optimal fertility and nutrient-poor soils requiring substantial inputs of synthetic fertilizers to support sustainable crop production. However, significant increases in the price of fertilizers mean many farmers, particularly in developing countries, cannot afford such management practises. The spiraling financial burden of fertilizers, combined with growing public anxiety of the environmental and health impacts of synthetic chemical additives, means that alternative strategies for sustainable crop production need to be examined urgently. Trichoderma strains produce a diverse array of secondary metabolites and secreted proteins. Trichoderma isolates have been shown to activate broad spectrum immunity, ameliorate a wide range of abiotic stresses such as salinity and drought, improve photosynthetic efficiency, enhance nutrient uptake, and significantly increase nitrogen use efficiency in crops. These important attributes can all contribute to the enhanced plant growth characteristics often evident upon inoculation. The positive agronomic traits of growth promotion, enhanced tolerance to abiotic stress and broad spectrum enhanced systemic immunity afforded by many Trichoderma strains are striking and unique. The ability to exploit the signaling networks activated by Trichoderma to establish these agriculturally beneficial traits requires an understanding of both the bioactive inducing molecules and the signaling networks targeted by these activators. The rapid developments in genomic and analytical technologies means this is an opportune time to exploit the amazing chemical diversity of soil micro-organisms such as Trichoderma, with the objective of improving PGP and ISR on a range of agronomically important plant species. Research conducted at Exeter has identified a novel strain of the naturally occurring rhizosphere fungus Trichoderma hamatum (strain GD12) that improves crop productivity and imparts broad spectrum enhanced immunity to pathogens in the absence of costly fertilizers and environmentally damaging agrochemicals. At present, the mechanism underlying the plant-growth-promotion and enhanced systemic resistance phenomena are unknown and this proposal lays the foundations to address the molecular basis of the inducing bioactives and the plant response pathways targeted by these bioactives. This combined knowledge is important, and necessary to contemplate translating Trichoderma PGP and ISR into the agricultural arena. This multidisciplinary research programme will use a combination of genetics, genomics and metabolomics to unravel Trichoderma PGP/ISR bioactives, capture the plant transcriptional reprogramming induced by the bioactives and identify key components of the PGP, ISR signaling networks. We will use comparative transcriptomics to characterize signaling pathways in Arabidopsis and rice activated by Trichoderma inoculation. In combination with mutant Trichoderma and Arabidopsis lines compromised in phytohormone signaling we will identify candidate signaling components/pathways that contribute to PGP and ISR. We will undertake comparative metabolic profiling using liquid chromatography mass spectrometry to characterize the bioactives and test their efficacy on different plants with the objective of developing novel natural agrochemicals.