Methods and compositions for improving plant traits

Inventors

Temme, Karsten • Tamsir, Alvin • BLOCH, Sarah • CLARK, Rosemary • TUNG, Emily

Assignees

Pivot Bio Inc

Abstract

Disclosed herein are methods of increasing nitrogen fixation in a non-leguminous plant. The methods can comprise exposing the plant to a plurality of bacteria. Each member of the plurality comprises one or more genetic variations introduced into one or more genes or non-coding polynucleotides of the bacteria's nitrogen fixation or assimilation genetic regulatory network, such that the bacteria are capable of fixing atmospheric nitrogen in the presence of exogenous nitrogen. The bacteria are not intergeneric microorganisms. Additionally, the bacteria, in planta, produce 1% or more of the fixed nitrogen in the plant.

Core Innovation

The disclosure describes methods and compositions to increase nitrogen fixation in a corn plant by exposing the plant to a plurality of engineered diazotrophs. The engineered diazotrophs comprise at least one genetic variation introduced in a nitrogen fixation genetic regulatory network, and the genetic variation increases expression or activity of nifH. The disclosed microorganisms are non-intergeneric microorganisms.

The introduced genetic variation comprises genetic material that originates from at least one organism of the same genus as the plurality of engineered diazotrophs. The disclosure indicates that engineered diazotrophs can enable atmospheric N2 fixation in the presence of exogenous nitrogen, including fertilizer nitrogen. In embodiments, bacteria in planta produce fixed nitrogen at levels such as ≥1%, ≥5%, or ≥10% fixed nitrogen.

The disclosure also describes genetic targets and regulatory approaches associated with nitrogen fixation and nitrogen assimilation, including nif gene cluster regulatory and nitrogen assimilation genes. It further describes host-microbe evolution including serial passage to evolve improved strains, and evaluation concepts such as acetylene reduction assay, in planta colonization, transcriptomic profiling, and 15N-based nitrogen attribution. The disclosure additionally describes seed-coating and formulation/composition details and includes ATCC deposited isolates.

Claims Coverage

The independent claim provides coverage for a method performed in a field in corn plants, using engineered diazotrophs with a specific nifH-regulatory-network genetic variation derived from organisms of the same genus, resulting in an increased amount of atmospheric derived nitrogen relative to non-engineered diazotrophs.

Overall claim coverage centers on field exposure of corn to engineered diazotrophs carrying same-genus-origin genetic variation in a nitrogen fixation regulatory network that increases nifH expression or activity, producing increased atmospheric derived nitrogen relative to non-engineered diazotrophs.

Stated Advantages

Documented Applications