Generation of biomass

Abstract

A method for manipulating the growth and/or structure of a plant, for increasing biomass by increasing the expression and/or activity of PXY and/or CLE in the vascular tissue of a plant. The method includes introducing into the plant a regulatory element which specifically directs expression of CLE in the vascular tissue of the plant, where expression and/or activity of CLE modified in the vascular tissue remains substantially unaltered in non-vascular tissue of the modified plant.

1 . A method for manipulating the growth and/or structure of a plant comprising modifying the plant to specifically increase the expression and/or activity of CLE in the vascular tissue of the plant compared to the expression and/or activity of CLE in the vascular tissue of a wild type plant of the same species maintained under identical conditions, the process comprising:
 introducing into the plant a regulatory element which specifically directs expression of CLE in the vascular tissue of the plant,   wherein expression and/or activity of CLE modified in the vascular tissue remains substantially unaltered in non-vascular tissue of the modified plant,   wherein the regulatory element comprises an PP2 promoter sequence produced by using the primer sequence of SEQ. ID. NO. 20, and   wherein the CLE comprises the polypeptide sequence of SEQ. ID. NO. 39.   
     
     
         2 . The method according to  claim 1 , wherein CLE is CLE41 or CLE42 or CLE44. 
     
     
         3 . The method according to  claim 1 , further comprising modifying the plant to specifically increase the expression and/or activity of one or more of CLE41, CLE42 or CLE44 in the vascular tissue of the plant compared to the expression and/or activity of the respective CLE in the vascular tissue of a wild type plant of the same species maintained under identical conditions, wherein expression and/or activity of the one or more of CLE41, CLE42 or CLE44 modified in the vascular tissue remains substantially unaltered in non-vascular tissue of the modified plant. 
     
     
         4 . The method according to  claim 1 , wherein the method comprises introducing into the plant a regulatory element which specifically directs expression of one or more of CLE41, CLE42 or CLE44 in the phloem of the plant. 
     
     
         5 . The method according to  claim 1 , wherein the regulatory element is derived from hybrid Aspen. 
     
     
         6 . The method according to  claim 1 , wherein the regulatory element is provided in an expression cassette, operably linked to a nucleic acid molecule encoding CLE. 
     
     
         7 . The method according to  claim 1 , wherein the regulatory element is provided in an expression cassette which comprises sequences for insertion of the regulatory element into the plant genome, operably linked to the native CLE gene. 
     
     
         8 . The method according to  claim 7 , wherein the expression cassette is provided in a vector. 
     
     
         9 . The method according to  claim 8 , wherein the vector is capable of propagating in both a bacterial host cell and a plant cell. 
     
     
         10 . The method according to  claim 8  further comprising the step of:
 introducing the expression cassette or vector into a plant cell. 
 
     
     
         11 . The method according to  claim 1  further comprising:
 measuring expression of CLE by measuring the relative amounts of the gene product(s) in a cell or tissue extracted from the modified plant and comparing it to the level of said gene products(s) in a corresponding cell or tissue from a wild type plant of the same species maintained under identical conditions. 
 
     
     
         12 . The method according to  claim 11 , wherein the levels of CLE are increased by at least about 20% compared to the level of CLE in a wild type plant maintained under identical conditions. 
     
     
         13 . The method according to  claim 11 , wherein the activity of CLE is increased by at least about 5% compared to the activity of CLE in a wild type plant maintained under identical conditions. 
     
     
         14 . The method according to  claim 11 , further comprising:
 measuring increased growth by measuring radial diameter, vigour, growth rate, the amount of leaf tissue, the amount of biomass, and/or seed yield in the modified plant comparing it to the corresponding phenotype in a corresponding cell or tissue from a wild type plant.   
     
     
         15 . The method according to  claim 14 , wherein increased growth is at least about 20% increase in radial diameter, vigour, growth rate, the amount of leaf tissue, the amount of biomass, and/or seed yield as compared to a wild type plant maintained under identical conditions. 
     
     
         16 . The method according to  claim 1 , wherein CLE is CLE41 or CLE42 and wherein the nucleic acid encoding CLE41 comprises SEQ. ID. 2 or 5 and wherein the nucleic acid encoding CLE42 is SEQ. ID. 29.