Methods and Compositions for Weed Control

A method for potentiating activity of a glutamine synthetase (GS) inhibitor herbicide in a plant comprising

• (a) applying to a surface of the plant a composition comprising at least one non-transcribable polynucleotide and a transfer agent,
• wherein the non-transcribable polynucleotide is from 18 to about 700 nucleotides in length and is identical or complementary to at least 18 contiguous nucleotides of a glutamine synthetase (GS) gene sequence or an RNA transcript of the GS gene sequence, wherein the GS gene sequence is selected from the group consisting of SEQ ID NOs:
• 1-4, 6, 7, 9, 10, 14, 16, 17, 20, 21, 23, 27-49, 51-59, and a polynucleotide fragment thereof, and
• wherein the transfer agent conditions the surface of the plant for permeation by the non-transcribable polynucleotide, and
• (b) applying the GS inhibitor herbicide to the plant;
• whereby the non-transcribable polynucleotide permeates the interior of the plant and induces suppression of the GS gene, thereby potentiating activity of the GS inhibitor herbicide in the plant.

A method of reducing growth, development, or reproductive ability in a plant, comprising

• treating a plant with a GS inhibitor herbicide in combination with
• (a) at least one non-transcribable polynucleotide that is
• from 18 to about 700 nucleotides in length and is identical or complementary to at least 18 contiguous nucleotides of a glutamine synthetase (GS) gene sequence or an RNA transcript of the GS gene sequence, wherein the GS gene sequence is selected from the group consisting of SEQ ID NOs:
• 1-4, 6, 7, 9, 10, 14, 16, 17, 20, 21, 23, 27-49, 51-59, and a polynucleotide fragment thereof, and
• (b) an organosilicone surfactant,
• whereby growth, development, or reproductive ability is reduced in the treated plant compared to a control plant treated with the GS inhibitor herbicide alone.