RESUMO
Dicot wood is mainly composed of cellulose, xylan and lignin, and its formation requires the coordinated regulation of their biosynthesis. In this report, we demonstrate that the poplar wood-associated MYB transcriptional activators, PtrMYB3 and PtrMYB20, activate the biosynthetic pathways of cellulose, xylan and lignin when overexpressed in Arabidopsis and they are also able to activate the promoter activities of poplar wood biosynthetic genes. We also show that PtrMYB3 and PtrMYB20 are functional orthologs of Arabidopsis MYB46 and MYB83, and their expression is directly activated by poplar PtrWND2, suggesting their involvement in the regulation of wood formation in poplar.
Assuntos
Parede Celular/metabolismo , Celulose/biossíntese , Proteínas de Plantas/metabolismo , Populus/genética , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Regulação da Expressão Gênica de Plantas , Genes myb , Filogenia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Populus/metabolismo , Regiões Promotoras Genéticas , RNA de Plantas/genética , Fatores de Transcrição/genética , Madeira/genética , Madeira/crescimento & desenvolvimentoRESUMO
Mossbauer, EPR, magnetic susceptibility, and DFT studies of the unusual two-coordinate iron(II) amide Fe[N(t-Bu)(2)](2) show that it retains a linear N-Fe-N framework due to the nonbonding delta nature of the (xy, x(2)-y(2)) orbitals. The resulting near-degenerate ground state gives rise to a large magnetic moment and a remarkably large internal hyperfine field. The results confirm that extraordinary orbital magnetic effects can arise in linear transition metal complexes in which orbital degeneracies are not broken by Jahn-Teller or Renner-Teller distortions.