An Antisense Pectin Methylesterase Gene Alters Pectin Chemistry and Soluble Solids in Tomato Fruit.
An Antisense Pectin Methylesterase Gene Alters Pectin Chemistry and Soluble Solids in Tomato Fruit.
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DOI：
10.1105/tpc.4.6.667
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发表时间：
1992-06
期刊：
影响因子：
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通讯作者：
D. Tieman;R. Harriman;G. Ramamohan;A. Handa
中科院分区：
文献类型：
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作者：
D. Tieman;R. Harriman;G. Ramamohan;A. Handa
果胶甲酯酶（PME，EC 3.1.11）使果胶脱甲氧基，并且被认为参与成熟番茄果实中多聚半乳糖醛酸酶对果胶细胞壁组分的降解。我们将反义和正义嵌合PME基因导入番茄，以阐明PME在果实发育和成熟中的作用。转基因植株的果实表达高水平的反义PME RNA显示出<10%的野生型PME酶活性和不可检测的PME蛋白和mRNA水平。较低的PME酶活性在转基因植物的果实与果胶的分子量和甲酯化的增加和细胞壁中的总和螯合剂可溶性polyuronides的水平降低。转基因植物的果实也比野生型果实含有更高水平的可溶性固形物。这种性状在随后的世代中保持，并以正常的孟德尔方式与反义PME基因分离。这些结果表明，PME酶活性的降低在成熟的番茄果实有显着的影响，果实果胶的代谢和可溶性固形物含量的增加，但不干扰成熟过程。
Pectin methylesterase (PME, EC 3.1.11) demethoxylates pectins and is believed to be involved in degradation of pectic cell wall components by polygalacturonase in ripening tomato fruit. We have introduced antisense and sense chimeric PME genes into tomato to elucidate the role of PME in fruit development and ripening. Fruits from transgenic plants expressing high levels of antisense PME RNA showed <10% of wild-type PME enzyme activity and undetectable levels of PME protein and mRNA. Lower PME enzyme activity in fruits from transgenic plants was associated with an increased molecular weight and methylesterification of pectins and decreased levels of total and chelator soluble polyuronides in cell walls. The fruits of transgenic plants also contained higher levels of soluble solids than wild-type fruits. This trait was maintained in subsequent generations and segregated in normal Mendelian fashion with the antisense PME gene. These results indicate that reduction in PME enzyme activity in ripening tomato fruits had a marked influence on fruit pectin metabolism and increased the soluble solids content of fruits, but did not interfere with the ripening process.