title: Overexpression of constitutively active Arabidopsis RabG3b promotes xylem development in transgenic poplars.
abstract: An Arabidopsis small GTPase, RabG3b, was previously characterized as a component of autophagy and as a positive regulator for xylem development in Arabidopsis. In this work, we assessed whether RabG3b modulates xylem-associated traits in poplar in a similar way as in Arabidopsis. We generated transgenic poplars (Populus alba × Populus tremula var. glandulosa) overexpressing a constitutively active form of RabG3b (RabG3bCA) and performed a range of morphological, histochemical and molecular analyses to examine xylogenesis. RabG3bCA transgenic poplars showed increased stem growth due to enhanced xylem development. Autophagic structures were observed in differentiating xyelm cells undergoing programmed cell death (PCD) in wild-type poplar, and were more abundant in RabG3bCA transgenic poplar plants and cultured cells. Xylogenic activation was also accompanied by the expression of secondary wall-, PCD- and autophagy-related genes. Collectively, our results suggest that Arabidopsis RabG3b functions to regulate xylem growth through the activation of autophagy during wood formation in Populus, as does the same in Arabidopsis.
authors: School of Life Sciences and Biotechnology, Korea University, Seoul 136-701, Korea.
authors: Soon Il
authors: SI
authors: Kwon
authors: Hong Joo
authors: HJ
authors: Cho
authors: Jae-Soon
authors: JS
authors: Lee
authors: Hyunjung
authors: H
authors: Jin
authors: Soo-Jeong
authors: SJ
authors: Shin
authors: Mi
authors: M
authors: Kwon
authors: Eun Woon
authors: EW
authors: Noh
authors: Ohkmae K
authors: OK
authors: Park
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D001343:Autophagy; D002473:Cell Wall / Q000737:chemistry; D002482:Cellulose / Q000737:chemistry; D018506:Gene Expression Regulation, Plant; D018547:Plant Stems / Q000737:chemistry / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development; D032107:Populus / Q000235:genetics / Q000254:growth & development*; D014934:Wood / Q000235:genetics / Q000254:growth & development; D052584:Xylem / Q000737:chemistry / Q000254:growth & development*; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D002482:Cellulose; C556156:RabG3b protein, Arabidopsis; D020691:rab GTP-Binding Proteins