The invention discloses isolated polynucleotides and polypeptides, and recombinant DNA constructs useful for conferring drought tolerance and/or improved nitrogen use efficiency; compositions (such as plants or seeds) comprising these recombinant DNA constructs; and methods utilizing these recombinant DNA constructs. The recombinant DNA constructs comprise a polynucleotide operably linked to a promoter that is functional in a plant, wherein said polynucleotides encode glutamate receptor polypeptides.