Gene Expression of Secale cereale (Fall Rye) Grown in Petroleum Hydrocarbon (PHC) Impacted Soil With and Without Plant Growth-Promoting Rhizobacteria (PGPR), Pseudomonas putida

Phytoremediation employs plants to sequester, degrade, and transform contaminants. This remediation technology depends on sufficient plant growth, often not achievable with high contaminant concentrations. One way to improve plant growth on impacted soils is by using plant growth-promoting rhizobacteria (PGPR). PGPR are naturally occurring soil microbes that stimulate plant growth through variety of means. We examined what changes in gene expression occurred in a grass species Secale cereale treated with PGPR, Pseudomonas putida PGPR (UW4), grown in petroleum hydrocarbon (PHC) impacted soil. UW4 promoted plant growth on the PHC impacted soil. Using differential display polymerase chain reaction (ddPCR), six genes were identified based on their altered expression as an effect of PHC exposure and plant PGPR treatment. The changes in levels of expression of selected genes were measured using quantitative PCR (qPCR). There was upregulation of all six genes examined, two of which were statistically significant. In roots, two genes were upregulated significantly and one gene appeared to be downregulated.