Variable effects of biostimulants on growth of Chenopodium spp under abiotic stress

Abiotic stressors such as drought, high heat, and nutrient depletion greatly impact agricultural yields. Many plant-associated beneficial microorganisms can alleviate the effects of abiotic stress on crops by producing phytohormones, increasing water access, and transforming soil nutrients to bioavailable forms for plant uptake. These beneficial microbes have the potential to reduce our use of traditional chemical fertilizers without sacrificing crop productivity. The objectives of this study were to evaluate the effects of biostimulants and abiotic stress on the growth of 1) Chenopodium quinoa and 2) its wild relative C. ficifolium. We performed controlled environment growth room studies to evaluate the effect of one commercial biostimulant and two novel bacterial strains isolated from C. berlandieri (NFB28.1 and PSB37.3) on C. quinoa growth under drought and nutrient-depleted conditions. We also evaluated the effect of a commercial biostimulant, Lalrise Start SC, on C. ficifolium as a potential model for inferring microbial interactions with quinoa. Our results show that NFB28.1 (Achromobacter insolitus) and PSB37.3 (Microbacterium sp.) did not impact plant growth under stress conditions compared to water controls. However, Lalrise Start SC significantly increased quinoa aboveground biomass and photosynthetic activity under drought and nutrient stress, respectively. Here we show that C. ficifolium may not be an adequate model for quinoa to predict microbial interactions however, more research must be done to compare the effectiveness of biostimulants on these two species. This study is the first to characterize of the effects of a commercial biostimulant on C. quinoa and C. ficifolium, as well as the first in vivo characterization of the impact of New Hampshire soil microbes on quinoa.