Assessment and Comparison of Ornamental Plant Disease Resistance and Plant Growth as Effected by Microbial Inoculants

Ornamental plants in their early stages reside largely in greenhouses, due to this, greenhouse pathogens, such as Botrytis cinerea, which causes gray mold, are detrimental to the plant population. This study had two aims. Aim 1 was to assess the disease resistance in Petunia x hybrida using the two ACC deaminase-producing bacteria Pseudomonas putida strain UW4 + and Pseudomonas fluorescens strain Wood3 and commercially available products, the second aim was to determine which genes were induced by treatment with Wood 3, UW4+ and the commercially available products. The biocontrol activity of Wood3 will be analyzed using a lab-grown strain and the commercial strain in VIAH1. Wood3 will also be compared against additional ACC deaminase producing bacteria, UW4+ and commercial biocontrol products including Root Shield, Trichoderma harzianum, and Actinovate, Streptomyces lydicus. The plants were inoculated twice with the beneficial treatments, once in a plug tray at 28 days, and once four days after transplant at 49 days followed by an inoculation of Botrytis cinerea at 56 days using 2 liter hand sprayers to mist the plants to run off. The plants were rated for disease progression on the flowers and overall disease progression for a two-week period. The expression of PhPr3 in petunia leaves 64 days after inoculation with these beneficial microbes was analyzed through qPCR on the PhPR3 gene. Overall beneficial microbe biocontrol treatment did aid the ornamental plant, petunia against the pathogen, Botrytis cinerea, however, more testing with a larger sample size is needed. Gene expression was inconclusive and the primers need more optimization for the target genes