Isolated polynucleotides and polypeptides, and methods of using same for increasing nitrogen use efficiency, yield, growth rate, vigor, biomass, oil content, and/or abiotic stress tolerance

A method of increasing tolerance of a plant to nitrogen deficiency, wherein the nitrogen deficiency is a growth condition including an applied level of nitrogen which is below a level needed for a metabolism, growth, reproduction and/or viability of a control plant of the same species, the method comprising:

• (a) expressing within the plant a heterologous polynucleotide comprising a nucleic acid sequence encoding a polypeptide comprising an amino acid sequence as set forth by SEQ ID NO:
• 475, or a homologous polypeptide having at least 83% sequence identity and conservative amino acid substitution(s) with respect to the amino acid sequence set forth by SEQ ID NO:
• 475, and
• (b) selecting said plant expressing said heterologous polynucleotide for an increased tolerance to nitrogen deficiency as compared to a control plant of the same species which is grown under the same growth conditions,
• thereby increasing the tolerance of the plant to nitrogen deficiency.

A method of increasing leaf number, rosette area, rosette diameter, plot coverage, growth rate of leaf number, growth rate of plot coverage and/or growth rate of rosette diameter of a plant, comprising:

• (a) expressing within the plant a heterologous polynucleotide comprising a nucleic acid sequence encoding a polypeptide comprising an amino acid sequence as set forth by SEQ ID NO:
• 475, or a homologous polypeptide having at least 83% sequence identity and conservative amino acid substitution(s) with respect to the amino acid sequence set forth by SEQ ID NO:
• 475, and
• (b) selecting said plant expressing said heterologous polynucleotide for an increased leaf number, rosette area, rosette diameter, plot coverage, growth rate of leaf number, growth rate of plot coverage and/or growth rate of rosette diameter as compared to a control plant of the same species which is grown under the same growth conditions,
• thereby increasing the leaf number, rosette area, rosette diameter, plot coverage, growth rate of leaf number, growth rate of plot coverage and/or growth rate of rosette diameter of the plant.