The structure and regulation of homeologous tobacco endochitinase genes of Nicotiana sylvestris and N. tomentosiformis origin
The structure and regulation of homeologous tobacco endochitinase genes of Nicotiana sylvestris and N. tomentosiformis origin
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烟草和绒毛烟草同源烟草内切几丁质酶基因的结构和调控
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
F. Meins
中科院分区：
文献类型：
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作者：
M. Buuren;J. Neuhaus;H. Shinshi;J. Ryals;F. Meins
I类几丁质酶被认为在植物诱导的防御反应中起重要作用。我们分离并部分鉴定了烟草中编码这些酶的基因亚家族CHN14和CHN50两个成员的基因组克隆。哈瓦那425。先前克隆的CHN14、CHN50和CHN48基因的编码序列在79 ~ 95%的位置上是相同的。烟草是一种双二倍体植物，其祖先与现代物种N. sylvestris和N. tomentosiformis关系最密切。基因组DNA的Southern分析、推导的氨基酸序列的比较和纯化酶的部分测序表明，CHN48/CHN50和CHN14/CHN14′基因对是同源物。编码几丁质酶A （Mr . 34 kDa）的基因CHN48和基因CHN14来自毛毛象；而编码几丁质酶B （Mr . 32 kDa）的基因CHN50和基因CHN14 '则来源于N. sylvestris。I类几丁质酶是在乙烯处理过的植物叶片或受到真菌病原菌烟草Cercospora nicotianae感染的植物叶片以及转移到未添加生长素和细胞分裂素的培养基中的培养细胞中诱导产生的。核糖核酸酶保护实验表明，在这些条件下，同源物CHN48和CHN50编码的转录本占总几丁质酶mRNA的约90%。较少丰富的转录本CHN48始终表现出比CHN50更大的诱导程度。同源物CHN14和CHN14′的表达量占几丁质酶mRNA总量的10%以下。它们显示出与CHN48和CHN50相似的激素调节模式，但这些基因的转录本在烟叶中未被检测到。因此，这两组同源物受激素的调节方式相同，但对病原体感染的反应不同。
SummaryThe fungicidal class I chitinases are believed to be important in the induced defense response of plants. We isolated and partially characterized genomic clones representing two members, CHN14 and CHN50, of the gene subfamily encoding these enzymes in Nicotiana tabacum L. cv. Havana 425. The coding sequences of genes CHN14, CHN50, and CHN48, which was cloned earlier, are identical at 79–95% of the positions. Tobacco is an amphidiploid species derived from ancestors most closely related to the present-day species N. sylvestris and N. tomentosiformis. Southern analysis of genomic DNA, comparison of deduced amino acid sequences, and partial sequencing of the purified enzymes suggest that the gene pairs CHN48/CHN50 and CHN14/CHN14′ are homeologues. Gene CHN48, which encodes chitinase A (Mr ca. 34 kDa), and gene CHN14 are derived from N. tomentosiformis; whereas gene CHN50, which encodes chitinase B (Mr ca. 32 kDa), and gene CHN14′ are derived from N. sylvestris. Class I chitinases are induced in leaves of plants treated with ethylene or infected with the fungal pathogen Cercospora nicotianae and in cultured cells transferred to medium without added auxin and cytokinin. RNase protection assays show that under these conditions transcripts encoded by the homeologues CHN48 and CHN50 account for > 90% of the total chitinase mRNA. The less abundant transcript, CHN48, consistently showed a greater degree of induction than CHN50. Expression of the homeologues CHN14 and CHN14′ represented < 10% of the total chitinase mRNA. They showed a pattern of hormonal regulation similar to CHN48 and CHN50, but transcripts of these genes were not detected in leaves infected with C. nicotianae. Therefore the two sets of homeologues are regulated in the same way by hormones and respond differently to infection by a pathogen.
影响因子：
11.6
作者：
NEALE, AD;WAHLEITHNER, JA;DENNIS, ES
通讯作者：
DENNIS, ES