Polynucleotides and polypeptides encoded therefrom and methods of using same for increasing biomass in plants and plants generated thereby

Abstract

A method of increasing biomass, vigor and/or yield of a plant is disclosed. The method comprises expressing within the plant an exogenous polypeptide comprising a UGGPase activity. The polypeptide may comprise an amino acid sequence at least 90% homologous, and/or at least 80% identical to SEQ ID NO: 33 as determined using the BlastP software of the National Center of Biotechnology Information (NCBI) using default parameters. Polynucleotides encoding same and plants expressing same are also disclosed.

1 . A plant cell comprising an exogenous polypeptide comprising a UGGPase activity. 
     
     
         2 . The plant cell of  claim 1 , wherein said plant cell forms a part of a plant. 
     
     
         3 . The plant cell of  claim 1 , wherein said exogenous polypeptide has an amino acid sequence at least 90% homologous, and/or at least 80% identical to SEQ ID NO: 33 as determined using the BlastP software of the National Center of Biotechnology Information (NCBI) using default parameters. 
     
     
         4 . The plant cell of  claim 1 , wherein said UGGPase activity comprises a higher affinity for a Glucose-1-phosphate than a Galactose-1-phophate. 
     
     
         5 . The plant cell of  claim 1 , wherein a maximum enzyme velocity (V max ) of said UGGPase activity is higher for a Galactose-1-phosphate than a Glucose-1-phosphate. 
     
     
         6 . The plant cell of  claim 1 , wherein said exogenous polypeptide comprises a higher enzymatic activity towards a galactose substrate than an enzymatic activity of a UGPase for a galactose substrate. 
     
     
         7 . The plant cell of  claim 1 , wherein said polypeptide is capable of converting Gal-1-phosphate to UDP-Gal and further is capable of converting UDP-glucose to glucose-1-phosphate. 
     
     
         8 . The plant cell of  claim 1 , further comprising an exogenous UGPase. 
     
     
         9 . The plant cell of  claim 8 , wherein said exogenous UGpase comprises an amino acid sequence as set forth in SEQ ID NO: 35. 
     
     
         10 . A method of increasing biomass, vigor and/or yield of a plant comprising expressing within the plant an exogenous polypeptide comprising a UGGPase activity, thereby increasing biomass, vigor and/or yield of the plant. 
     
     
         11 . The method of  claim 10 , wherein said exogenous polypeptide comprises an amino acid sequence at least 90% homologous, and/or at least 80% identical to SEQ ID NO: 33 as determined using the BlastP software of the National Center of Biotechnology Information (NCBI) using default parameters. 
     
     
         12 . The method of  claim 10 , wherein said expressing is effected by introducing to said plant a nucleic acid construct which comprise a polynucleotide sequence encoding said polypeptide and at least one promoter capable of directing transcription of said polynucleotide in said plant cell. 
     
     
         13 . The method of  claim 12 , wherein said at least one promoter is a constitutive promoter. 
     
     
         14 . The method of  claim 12 , wherein said at least one promoter is an inducible promoter. 
     
     
         15 . The method of  claim 12 , wherein said expressing is effected by infecting said plant with a virus. 
     
     
         16 . The method of  claim 15 , wherein said virus is an avirulent virus. 
     
     
         17 . The method of  claim 10 , further comprising expressing within the plant an exogenous UGPase. 
     
     
         18 . An isolated polynucleotide comprising a nucleic acid sequence encoding a polypeptide having an amino acid sequence at least 90% homologous, and/or at least 80% identical to SEQ ID NO: 33 as determined using the BlastP software of the National Center of Biotechnology Information (NCBI) using default parameters, wherein said polypeptide comprises a UDP glucose/galactose pyrophosphorylase (UGGPase) activity.