Field inoculations of nitrogen fixing endophytes on turfgrass

Abstract

Turfgrass is the number one irrigated crop in the United States. Lawn care regimes require high chemical fertilizer and water inputs. Endophytes, defined as microorganisms that live within plants, have the potential to decrease the high water and high fertilizer requirements of turfgrass. This study evaluated the inoculation of multiple mutualistic endophytes on a commonly planted turfgrass mix in field trials. Previous studies, in greenhouse and lab settings, found these same endophytes increase drought tolerance and grass greenness. Nine 3 ft by 3 ft turfgrass plots were inoculated with an endophyte consortium in the spring and fall of 2017. Inoculated plots were compared with non-inoculated controls for overall chlorophyll content, overall plot greenness, and mean total height accumulation. The results of the study indicated that there was no significant effect of endophyte inoculations on the turfgrass. Additionally, endophytes were extracted, cultured and sequenced from the plots two months post inoculation. The endophytes applied were not detected, indicating that they were unable to survive the entire growing season within the turfgrass. The current research will be one of the first studies to show that endophytes, inoculated onto a novel host, were unable to survive field conditions in a perennial crop and yield the benefits that were observed in vitro and in greenhouse trials. Future research should evaluate the success of these endophytes on other plant species in the field and in non-limiting environments and run a quantitative PCR experiment using isolate specific primers to determine endophyte survival over time in the field.