The bacterial Methylorubrum extorquens product TS201 induces multiple modes of action to reduce Diabrotica virgifera virgifera western corn rootworm feeding damage in maize

Pink-pigmented facultative methylotrophs (PPFMs) in the genera Methylobacterium and Methylorubrum are highly abundant members of the plant microbiome. When applied in an agricultural context, these beneficial native bacteria can help crops in a variety of ways including increasing yield, supporting defense from pests or pathogens, and improving nutrient use. TS201, an EPA-registered bioinsecticide product made from a Methylorubrum extorquens isolate, uses multiple modes of action to help maize plants withstand corn rootworm pressure. This includes priming the plant’s defense system from the beginning of the season while increasing root mass, altering root system architecture and promoting the regrowth of roots after damage. RNAseq experiments from field samples indicated an additional mode of action for repelling Diabrotica virgifera virgifera (western corn rootworm, WCR) feeding that was then tested in insect feeding choice assays.  When given a choice of a TS201-treated or untreated root, over 70% of WCR neonate larvae chose the untreated root. When the choice was two TS201-treated roots, over 80% remained undecided. GC-MS analyses are underway to further validate the mode of action. The combined modes of action of TS201 lead to decreased lodging which protects the ability to harvest. In 2023, large scale field trials at 66 locations indicated that TS201 showed +5.1 bu/ac advantage over grower standard practice with a 70% win-rate. The use of this microbial product complements existing crop protection and trait strategies as part of an integrated pest management program. These findings demonstrate a novel mode of action of PPFM-induced plants mitigating insect damage.