STTR Phase I: Biocontrol of Pythium pathogens in hydroponic greenhouses

这项小型企业创新研究（SBIR）第一阶段项目的更广泛影响/商业潜力是开发一种靶向生物农药，用于控制绿叶蔬菜水培温室生产中的病原菌。西红柿、黄瓜、辣椒、生菜和菠菜的新鲜市场生产正在转向水培温室操作，因为这些操作在土地、水和肥料的利用方面比传统操作更有效。尽管有这些优势，但病原菌对它们的经济生存能力构成了主要威胁。在这些操作中，偶然将病原菌引入循环水中可能导致作物完全损失，因为病原菌通过水迅速传播并感染根部，导致根部腐烂和叶片变黄。在生菜中，根部腐烂损害营养吸收，减慢植株生长速度。作物轮作周期必须延长，以生产相同数量的产品，可能需要对循环水进行紫外线照射，以减轻病害损失。植物根系完整性的降低可能使水中的致病菌通过植物维管系统迁移到叶片中，并可能引起疾病。已经报道了一例大肠杆菌污染生菜的案例。因此，有必要发展一种以有机为基础的方法来解决这一疾病问题。该项目将收集反映不同水培设施中这些病原体遗传多样性的病原菌。这种分离株的收集将考虑几个参数：1。2.地理多样性；作物种类（芝麻菜、罗勒、大麻、生菜和菠菜）；生产系统，如深水木筏水培，垂直水培系统和小规模，家庭经营。该项目将评估10种假单胞菌菌株，这些菌株对一小部分分离的python菌株表现出接触依赖性杀伤，以确定这些生物防治剂的最有效组合。生物信息学方法将用于鉴定负责杀伤表型的基因。将在测序菌株中进行靶向基因缺失，突变菌株的毒力测定将用于评估特定基因的作用。这一策略有望确定寄主特异性杀死毕氏菌的遗传基础，并提供证据证明这些微生物不是人类或植物的病原体。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.