The role of PopCel1 and PopCel2 in poplar leaf growth and cellulose biosynthesis.
Poplar calli transcribed two cellulase (endo-1,4-beta-glucanase) genes, PopCel1 and PopCel2, whose mRNAs were differentially located in the growing leaves of poplar during cell wall synthesis. Histochemical and RT-PCR analyses of promoter-GUS fusion gene activities in transgenic poplar demonstrated that PopCel1 promoter-derived GUS activity was localized in the petiole and leaf veins, whereas PopCel2 was confined to mesophyll cells and disappeared from the tip during the development of leaves. Autoradiography of the leaf showed that the radioactivity of [14C]sucrose incorporated into cellulose corresponded to the combination of the sucrose-induced tissue-specific patterns of PopCel1 and PopCel2. Interestingly, 2,6-dichlorobenzonitrile (DCB) not only inhibited the incorporation of the radioactivity into cellulose, but also repressed the induction of both cellulase genes. Suppression of cellulases by expression of PopCel1 antisense cDNA or co-suppression of PopCel1 mRNA by overexpression of PopCel1 sense cDNA reduced leaf growth. Therefore, we came to the conclusion that PopCel1 and PopCel2 probably function to promote leaf growth in poplar by the endohydrolysis of 1,4-beta-glucan.
Ohmiya
Yasunori
Y
Wood Research Institute, Kyoto University, Uji, Kyoto 611-0011, Japan.
Nakai
Tomonori
T
Park
Yong Woo
YW
Aoyama
Takashi
T
Oka
Atsuhiro
A
Sakai
Fukumi
F
Hayashi
Takahisa
T
D016375:Antisense Elements (Genetics) / Q000235:genetics; D002480:Cellulase / Q000235:genetics / Q000378:metabolism*; D002482:Cellulose / Q000096:biosynthesis*; D003001:Cloning, Molecular; D004790:Enzyme Induction / Q000187:drug effects; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D030821:Plants, Genetically Modified; D032107:Populus / Q000201:enzymology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism / Q000494:pharmacology
D016375:Antisense Elements (Genetics); D012333:RNA, Messenger; D013395:Sucrose; D002482:Cellulose; D002480:Cellulase