Manipulation of Ammonium Transporters (AMTS) to Improve Nitrogen Use Efficiency in Higher Plants

Abstract

The present invention provides polynucleotides and related polypeptides of the protein AMT. The invention provides genomic sequence for the AMT gene. AMT is responsible for controlling nitrogen utilization efficiency in plants.

1 . An isolated polynucleotide selected from the group consisting of:
 a. a polynucleotide having at least 70% sequence identity, as determined by the GAP algorithm under default parameters, to the full length sequence of a polynucleotide selected from the group consisting of SEQ ID NOS: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79 or 81; wherein the polynucleotide encodes a polypeptide that functions as a modifier of AMT;   b. a polynucleotide encoding a polypeptide selected from the group consisting of SEQ ID NO: 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80 or 82;   c. a polynucleotide selected from the group consisting of SEQ ID NOS: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79 or 81; and   d. A polynucleotide which is complementary to the polynucleotide of (a), (b) or (c).   
     
     
         2 . A recombinant expression cassette, comprising the polynucleotide of  claim 1 , wherein the polynucleotide is operably linked, in sense or anti-sense orientation, to a promoter. 
     
     
         3 . A host cell comprising the expression cassette of  claim 2 . 
     
     
         4 . A transgenic plant comprising the recombinant expression cassette of  claim 2 . 
     
     
         5 . The transgenic plant of  claim 4 , wherein said plant is a monocot. 
     
     
         6 . The transgenic plant of  claim 4 , wherein said plant is a dicot. 
     
     
         7 . The transgenic plant of  claim 4 , wherein said plant is selected from the group consisting of: maize, soybean, sunflower, sorghum, canola, wheat, alfalfa, cotton, rice, barley, millet, peanut, switchgrass, myscanthus, triticale and cocoa. 
     
     
         8 . A transgenic seed from the transgenic plant of  claim 4 . 
     
     
         9 . A method of modulating the AMT in plants, comprising:
 a. introducing into a plant cell a recombinant expression cassette comprising the polynucleotide of  claim 1  operably linked to a promoter; and   b. culturing the plant under plant cell growing conditions; wherein the   AMT in said plant cell is modulated.   
     
     
         10 . The method of  claim 9 , wherein the plant cell is from a plant selected from the group consisting of: maize, soybean, sunflower, sorghum, canola, wheat, alfalfa, cotton, rice, barley, millet, peanut, switchgrass, myscanthus, triticale and cocoa. 
     
     
         11 . A method of modulating the AMT in a plant, comprising:
 a. introducing into a plant cell a recombinant expression cassette comprising the polynucleotide of  claim 1  operably linked to a promoter;   b. culturing the plant cell under plant cell growing conditions; and   c. regenerating a plant form said plant cell; wherein the AMT in said plant is modulated.   
     
     
         12 . The method of  claim 11 , wherein the plant is selected from the group consisting of: maize, soybean, sorghum, canola, wheat, alfalfa, cotton, rice, barley, millet, peanut, switchgrass, myscanthus, triticale and cocoa. 
     
     
         13 . A method of decreasing the AMT transporter polypeptide activity in a plant cell, comprising:
 a. providing a nucleotide sequence comprising at least 15 consecutive nucleotides of the complement of SEQ ID NO: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79 or 81;   b. providing a plant cell comprising an mRNA having the sequence set forth in SEQ ID NO: 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79 or 81; and   c. introducing the nucleotide sequence of step (a) into the plant cell, wherein the nucleotide sequence inhibits expression of the mRNA in the plant cell.   
     
     
         14 . The method of  claim 13 , wherein said plant cell is from a monocot. 
     
     
         15 . The method of  claim 14 , wherein said monocot is maize, wheat, rice, barley, sorghum, switchgrass, myscanthus, triticale or rye. 
     
     
         16 . The method of  claim 13 , wherein said plant cell is from a dicot. 
     
     
         17 . The transgenic plant of  claim 4 , wherein the AMT transporter activity in said plant is decreased. 
     
     
         18 . The transgenic plant of  claim 17 , wherein the plant has enhanced root growth. 
     
     
         19 . The transgenic plant of  claim 17 , wherein the plant has increased seed size. 
     
     
         20 . The transgenic plant of  claim 17 , wherein the plant has increased seed weight. 
     
     
         21 . The transgenic plant of  claim 17 , wherein the plant has seed with increased embryo size. 
     
     
         22 . The transgenic plant of  claim 17 , wherein the plant has increased leaf size. 
     
     
         23 . The transgenic plant of  claim 17 , wherein the plant has increased seedling vigor. 
     
     
         24 . The transgenic plant of  claim 17 , wherein the plant has enhanced silk emergence. 
     
     
         25 . The transgenic plant of  claim 17 , wherein the plant has increased ear size. 
     
     
         26 . The transgenic plant of  claim 4 , wherein the AMT transporter activity in said plant is increased.