Plant growth promoting characteristics of Bacillus species associated with Chenopodium quinoa

Abstract

As demand for organic quinoa increases and production expands, organic methods, such as the use of plant growth promoting bacteria, are needed to sustain quinoa production. To better understand the potential of Bacillus species to promote growth and reduce disease in quinoa (Chenopodium quinoa), a survey of three Bacillus populations from Bolivian, Ecuadorean and domestic Chenopodium spp. was performed. Four Bacillus species groups common to all populations were tested, including the B. subtilis, B. megaterium, B. simplex, and B. cereus species groups. Nearly 500 isolates were assayed for tricalcium phosphate solubilization, phytase production, IAA production, chitinase production and fungal antagonism. Patterns of specific plant growth promoting phenotypes were observed in different Bacillus species groups across all populations. For example, the tricalcium phosphate phenotype was universal in the B. subtilis and B. megaterium species groups, whereas IAA production was only observed in the B. simplex and B. megaterium species groups. Chitinase production was observed in the B. cereus species group and rarely in other species groups, whereas phytase production was common to all species groups. Isolates with potential for improving quinoa sustainability were identified in this study and isolates with multiple characteristics or consortia of single character Bacilli will be examined in greenhouse and field studies.