Achievement

Marnie Rout demonstrated that plant invasion profoundly alters ecosystem processes. She has shown that the invasive plant Sorghum halepense harbors bacterial endosymbionts that increase its growth rate, biomass, chemical defenses, and allelochemicals. She also showed that Sorghum harbors pathogenic and mutualistic bacterial endosymbionts in its rhizomes, including N2-fixers, siderophore producers, and plant growth promoting bacteria. With its endosymbionts, Sorghum modifies the soil to have increased plant-available N, P, and K. Endosymbionts significantly increased plant biomass and altered resource allocation toward rhizomes. Sorghum with endosymbionts inhibited growth of a native prairie grass, and restricting endosymbionts removed this competitive invasive effect. Plants with endosymbionts also had increased level of a cyanide-based anti-herbivory compound in their leaves. She has shown that microbial endosymbionts can significantly contribute to plant invasion.