Transgenic plants expressing a MAPKKK protein kinase domain

A method for increasing stress resistance or tolerance in a plant, said method comprising the steps of:

• (a) introducing into plant cells a DNA construct comprising a DNA sequence encoding a constitutively active mitogen-activated protein kinase kinase kinase (MAPKKK), wherein said DNA sequence is operably linked to a promoter functional in plant cells to yield transformed plant cells, and wherein the DNA sequence encoding the constitutively active MAPKKK is selected from the group consisting of
• (I) a DNA sequence encoding a polypeptide of SEQ ID NO:7, 11, 15, or 19, and
• (ii) a DNA sequence encoding a polypeptide having at least 90% sequence identity to the polypeptide of (i), wherein said polypeptide retains the MAPKKK activity;
• and
• (b) regenerating a transgenic plant from said transformed plant cells, wherein said constitutively active MAPKKK is expressed in the cells of said transgenic plant at levels sufficient to induce stress resistance or tolerance in said transgenic plant.