Polynucleotides encoding polypeptides that increase the secondary growth of plants were identified. Introduction of the polynucleotides into plants produces plants having altered characteristics, such as increased secondary growth, increased phloem production, increased xylem production, increased number of internodes, and/or increased stem diameter. Expression of the polynucleotides in plants in the antisense orientation may produce plants that have decreased secondary growth, decreased phloem production, decreased xylem production, decreased numbers of internodes, and/or decreased stem diameter.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
 This invention was made with United States government support from the Department of Energy grant number E21788. The United States government has certain rights in this invention.