Temporally and spatially targeted dynamic nitrogen delivery by remodeled microbes
The present disclosure provides non-intergeneric remodeled microbes that are able to fix atmospheric nitrogen and deliver such to plants in a targeted, efficient, and environmentally sustainable manner. The utilization of the taught microbial products will enable farmers to realize more productive and predictable crop yields without the nutrient degradation, leaching, or toxic runoff associated with traditional synthetically derived nitrogen fertilizer, by mitigating or eliminating the need for exogenous nitrogen-containing fertilizers. The remodeled microbes have unique colonization and nitrogen fixation abilities, which enable the microbes to deliver nitrogen to a cereal plant in a spatially targeted (e.g. rhizospheric) and temporally targeted (e.g. during advantageous stages of plant's life cycle) manner. The microbes are able to replace the standard agricultural practice of sidedressing and enable a more environmentally sustainable form of farming. The present disclosure also provides methods of using non-intergeneric remodeled microbes, for example, to fix atmospheric nitrogen by reducing or eliminating the need for exogenous nitrogen-containing fertilizers, to increase yield, and to reduce infield variability in the yield.
1 . An agricultural composition engineered for reduced variability in mean corn yield, comprising:
a) a plurality of corn seeds; and
b) a plurality of non-intergeneric remodeled bacteria coated onto said plurality of corn seeds, wherein members of the plurality of non-intergeneric remodeled bacteria produce fixed N of at least about 5.49×10 −13 mmol of N per CFU per hour, and
wherein members of the plurality of non-intergeneric remodeled bacteria are capable of colonizing corn plants upon planting of said corn seeds and supplying the corn plants with fixed N, and
wherein the standard deviation of mean corn yield measured across a locus upon planting of said corn seeds is lower, as compared to a control plurality of corn seeds planted without said plurality of non-intergeneric remodeled bacteria.
2 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria produce in the aggregate at least about 15 pounds of fixed N per acre over the course of at least about 10 days to about 60 days upon planting of said corn seeds.
3 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria each produce fixed N of at least about 2.75×10 −12 mmol of N per CFU per hour.
4 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria are capable of colonizing the root surface of corn plants upon planting of said corn seeds.
5 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise at least one genetic variation introduced into at least one gene, or non-coding polynucleotide, involved in a pathway selected from the group consisting of: the nitrogen fixation or assimilation genetic regulatory network, exopolysaccharide production, endo-polygalaturonase production, trehalose production, and glutamine conversion.
6 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise at least one genetic variation introduced into at least one gene, or non-coding polynucleotide, involved in the nitrogen fixation pathway.
7 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise at least one genetic variation introduced into at least one gene, or non-coding polynucleotide, involved in the nitrogen assimilation pathway.
8 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise at least one genetic variation introduced into at least one gene, or non-coding polynucleotide, involved in the glutamine conversion pathway.
9 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise an introduced control sequence operably linked to at least one gene of the nitrogen fixation pathway.
10 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise an introduced control sequence operably linked to at least one gene of the nitrogen assimilation pathway.
11 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise a heterologous promoter operably linked to at least one gene of the nitrogen fixation pathway.
12 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise a heterologous promoter operably linked to at least one gene of the nitrogen assimilation pathway.
13 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise at least one genetic variation introduced into: nifA, nifL, ntrB, ntrC, polynucleotide encoding glutamine synthetase, glnA, glnB, glnK, drat, amtB, polynucleotide encoding glutaminase, glnD, glnE, nifJ, nifH, nifD, nifK, nifY, nifE, nifN, nifU, nifS, nifV, nifW, nifZ, nifM, nifF, nifB, nifQ, a gene associated with biosynthesis of a nitrogenase enzyme, bcsii, bcsiii, yjbE, fhaB, pehA, otsB, treZ, glsA2, or combinations thereof.
14 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise at least one genetic variation introduced into: nifA, nifL, rpoN, glnE, glnA, glsA2, amtB, bcsii, bcsiii, pehA, fhaB, dctA, phoB1, glnD, glgA, or combinations thereof.
15 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise at least one genetic variation introduced into glnA.
16 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise at least one genetic variation introduced into at least one gene, or non-coding polynucleotide, of the nitrogen fixation or assimilation genetic regulatory network that results in one or more of: increased expression or activity of NifA or glutaminase; decreased expression or activity of NifL, NtrB, glutamine synthetase, GlnB, GlnK, DraT, AmtB; decreased adenylyl-removing activity of GlnE; or decreased uridylyl-removing activity of GlnD.
17 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise at least one of: a mutated nifL gene that has been altered to comprise a heterologous promoter inserted into said nifL gene; a mutated glnE gene that results in a truncated GlnE protein lacking an adenylyl-removing (AR) domain; a mutated amtB gene that results in the lack of expression of said amtB gene; or combinations thereof.
18 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise bacteria selected from: Rahnella aquatilis, Klebsiella variicola, Achromobacter spiritinus, Achromobacter marplatensis, Microbacterium murale, Kluyvera intermedia, Kosakonia pseudosacchari, Enterobacter sp., Azospirillum lipoferum, Kosakonia sacchari , or combinations thereof.
19 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise bacteria selected from: bacteria deposited as NCMA 201701002, bacteria deposited as NCMA 201708004, bacteria deposited as NCMA 201708003, bacteria deposited as NCMA 201708002, bacteria deposited as NCMA 201712001, bacteria deposited as NCMA 201712002, or combinations thereof.
20 . The agricultural composition of claim 1 , wherein members of the plurality of non-intergeneric remodeled bacteria comprise bacteria with a nucleic acid sequence that shares at least about 90% sequence identity to a nucleic acid sequence selected from SEQ ID NOs: 177-260, 296-303, and 458-469.