STTR Phase I: Biocontrol of Pythium pathogens in hydroponic greenhouses

这一小型企业创新研究(SBIR)第一阶段项目的更广泛影响/商业潜力是开发一种有针对性的生物杀虫剂，用于控制水培温室绿叶蔬菜生产中的腐霉病原体。新鲜的番茄、黄瓜、辣椒、生菜和菠菜的市场生产正在转向水培温室作业，因为这些作业在利用土地、水和肥料方面比传统作业更有效率。尽管有这些优势，腐霉病原体仍然是它们经济生存能力的主要威胁。在这些操作中，如果腐霉病原体意外地引入循环水中，可能会导致作物完全损失，因为病原体在水中迅速传播，并感染根部，导致根腐病和叶片变黄。在生菜中，根腐病损害了养分的吸收，减缓了植物的生长速度。必须延长作物轮作周期以生产相同数量的产品，并可能需要对循环水进行紫外线(UV)照射以减少疾病损失。植物根的完整性降低可能会使水中的病原菌通过植物维管系统迁移到叶子中，并可能导致疾病。已经报告了一例被大肠杆菌污染的生菜病例。因此，有必要开发一种基于有机的方法来解决这一疾病问题。拟议的项目将汇集腐霉病原体的集合，反映不同水培设施中这些病原体的遗传多样性。这些分离物的收集将考虑几个参数：1.地理多样性，2.作物种类(芝麻、罗勒、大麻、生菜和菠菜)，3.生产系统，例如深水筏水培、垂直水培系统和小规模的家庭经营。该项目将评估10株假单胞菌，这些假单胞菌对较少的腐霉分离物中的所有腐霉菌株都表现出接触依赖的杀灭作用，以确定这些生防剂最有效的组合。生物信息学方法将被用来确定与杀戮表型有关的基因。将在测序的菌株中进行有针对性的基因删除，并将使用突变菌株的毒力分析来评估特定基因的作用。这一战略预计将确定寄主特定杀死腐霉物种的遗传基础，并提供证据证明这些微生物不是人类或植物的病原体。这一裁决反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase 1 project is to develop a targeted biological pesticide for the control of pythium pathogens in the hydroponic greenhouse production of leafy greens. Fresh market production of tomatoes, cucumbers, peppers, lettuce, and spinach is shifting to hydroponic greenhouse operations because these operations are more efficient in their use of land, water, and fertilizer than conventional operations. Despite these advantages, pythium pathogens are a major threat to their economic viability. The accidental introduction of pythium pathogens into the recirculating water in these operations can result in complete crop losses as the pathogen spreads rapidly through the water and infects the roots causing root rots and leaf yellowing. In lettuce, root rots impair nutrient absorption and slow plant growth rates. Crop rotation cycles must be extended to produce the same amount of product, and ultraviolet (UV) irradiation of the recirculating water may be needed to mitigate disease losses. The reduced integrity of plant roots may enable pathogenic bacteria in the water to migrate via the plant vascular system into the leaves and potentially cause disease. One such case of E. coli-contaminated lettuce has already reported. Thus, there is a need for the development of an organic-based approach for this disease problem. The proposed project will assemble a collection of pythium pathogens that reflects the genetic diversity of these pathogens in different hydroponic facilities. This collection of isolates will take into account several parameters: 1. geographic diversity, 2. crop species (arugula, basil, cannabis, lettuce, and spinach), and 3. production system e.g., deep water raft hydroponics, vertical hydroponic systems and small scale, family-owned operations. This project will evaluate 10 Pseudomonad strains that have exhibited contact-dependent killing of all pythium strains from a smaller collection of pythium isolates to identify the most potent combinations of these biocontrol agents. A bioinformatics approach will be used to identify the genes responsible for the killing phenotype. Targeted gene deletions will be made in a sequenced strain and virulence assays of the mutated strains will be used to assess the role of specific genes. This strategy is expected to identify the genetic basis for host-specific killing of pythium species and provide evidence that these microbes are not pathogens of humans or plants.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.