Determination and optimization of Bacillus subtilis traits required for its establishment, persistence and activities on plant roots

微生物对生物生态系统的健康至关重要。因此，使用植物有益的细菌作为有机添加剂来增加农业中的生长和病原体保护是当前过度使用化学品的有希望的替代方案。虽然这些产品中有许多已经上市，但其功效的不一致性是其在田间和温室中广泛使用的主要障碍。来自芽孢杆菌属的细菌，特别是枯草芽孢杆菌（subtilis）和韦莱斯芽孢杆菌（velezensis）种的细菌，在农业中生物解决方案的开发中具有中心意义。这些细菌具有许多植物生长促进（PGP）特性，例如直接刺激植物的新陈代谢，并帮助植物获得各种营养。大多数芽孢杆菌属物种分泌大量的抗微生物剂，并有利于植物对病原体感染的抗性，从而充当天然的生物杀虫剂和杀真菌剂。芽孢杆菌属物种还可以形成抗性内生孢子，这是产品配制的理想休眠状态。 关于有益的芽孢杆菌和植物之间相互作用的基本问题仍然没有答案，这减缓了我们制定持续有效产品的能力。在这项研究计划中，我们将探索三个基本问题，以更好地了解芽孢杆菌物种和植物之间的复杂相互作用。首先，我们将确定什么是调节根上芽孢杆菌休眠的环境条件。在同一目标下，我们还将评估芽孢杆菌孢子是否仍能对植物产生有益影响。其次，我们将确定什么是芽孢杆菌细胞组分，这是至关重要的建立和持久性的根在没有和存在竞争菌株。最后，我们将评估芽孢杆菌有益活性在植物根部表达的程度，以及如何在自然条件下增强其活性。这项研究计划将导致一个基本的理解在植物的相互作用的B。枯草芽孢杆菌和植物，为今后开发、使用和配制这种生物生长促进剂和农药提供关键信息。这些知识非常重要，因为它们是发展和建立可持续农业系统所必需的。

Microorganisms are essential for the good health of biotic ecosystems. Thus, use of plant-beneficial bacteria as organic amendments for increase growth and pathogen protection in agriculture is a promising alternative to the current over-usage of chemicals. While many of these products are already on the market, inconsistence in their efficacy is a major hurdle to their widespread usage in fields and greenhouses. Bacteria from the Bacillus genera, and in particular of the subtilis and velezensis species, are of central interest in the development of biological solutions in agriculture. These bacteria possess many plant growth-promoting (PGP) traits, such as direct stimulation of the metabolism of the plant, and aid for the plant to acquire diverse nutrients. Most Bacillus species secrete an arsenal of antimicrobials and favor the plant resistance's toward pathogen infections, thus acting as natural, biological pesticides and fungicides. Bacillus species can also form resistant endospores, a dormant state ideal for product formulation. Fundamental questions about the interaction between beneficial Bacillus and plants are still unanswered, which slows down our capacity to formulate consistently efficient products. In this research program, we will explore three fundamental questions with the aim of better understanding the complex interactions between Bacillus species and plants. First, we will determine what are the environmental conditions that modulate dormancy of Bacillus on roots. In the same objective, we will also evaluate if Bacillus spores can still exert beneficial effects on plants. Secondly, we will identify what are Bacillus cellular components that are critical for the establishment and persistence on roots in absence and in presence of competing strains. Finally, we will evaluate to what extent Bacillus beneficial activities are expressed when it is on plant roots, and how to potentiate their activities in natural conditions. This research program will lead to a fundamental comprehension of in planta interactions of B. subtilis and plants, providing key information for the future development, usage and formulation of this biological growth promoter and pesticide. These knowledge are very important, since they are necessary to develop and implant sustainable agricultural systems.