The role of PopCel1 and PopCel2 in poplar leaf growth and cellulose biosynthesis.
The role of PopCel1 and PopCel2 in poplar leaf growth and cellulose biosynthesis.
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DOI：
10.1046/j.1365-313x.2003.01695.x
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发表时间：
2003-03
期刊：
影响因子：
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通讯作者：
Y. Ohmiya;T. Nakai;Y. Park;T. Aoyama;A. Oka;F. Sakai;Takahisa Hayashi
中科院分区：
文献类型：
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作者：
Y. Ohmiya;T. Nakai;Y. Park;T. Aoyama;A. Oka;F. Sakai;Takahisa Hayashi
白杨愈伤组织中转录了两个纤维素酶基因PopCel 1和PopCel 2，这两个基因的mRNA在杨树生长叶片中的差异定位与细胞壁合成有关。对转基因白杨启动子-GUS融合基因活性的组织化学和RT-PCR分析表明，PopCel 1启动子来源的GUS活性定位于叶柄和叶脉中，而PopCel 2启动子来源的GUS活性则定位于叶肉细胞中，并在叶片发育过程中从叶尖消失。叶的放射自显影显示，[14 C]蔗糖掺入纤维素的放射性对应于蔗糖诱导的组织特异性模式的PopCel 1和PopCel 2的组合。有趣的是，2，6-二氯苯腈（DCB）不仅抑制了放射性掺入纤维素，而且还抑制了两种纤维素酶基因的诱导。抑制纤维素酶表达的PopCell 1反义cDNA或共抑制的PopCell 1 mRNA过表达的PopCell 1正义cDNA降低叶片生长。因此，PopCel 1和PopCel 2可能通过内切水解1，4-β-葡聚糖来促进白杨叶片生长。
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.