Metabolic pathway engineering in cotton: Biosynthesis of polyhydroxybutyrate in fiber cells
Metabolic pathway engineering in cotton: Biosynthesis of polyhydroxybutyrate in fiber cells
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DOI：
10.1073/pnas.93.23.12768
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发表时间：
1996-11-12
影响因子：
11.1
通讯作者：
Keller, G
中科院分区：
文献类型：
--
作者：
John, ME;Keller, G
真养产碱杆菌编码β-酮硫解酶（phaA）、乙酰乙酰辅酶A还原酶（phaB）和聚羟基链烷酸酯合酶（phaC）的基因催化由乙酰辅酶A产生脂肪族聚酯聚-D-（-）-3-羟基丁酸酯（PHB）。PHB是一种热塑性聚合物，当在棉花中合成时，可以改变纤维特性。棉花纤维中存在内源性β-酮硫解酶活性，因此采用基因枪法将工程phaB和phaC基因转化棉花，并根据标记基因β-葡萄糖醛酸酶（GUS）的表达筛选转基因植株。10株转基因植株的纤维中同时表达phaB基因，8株同时表达phaB和phaC基因。电镜观察表明，同时表达phaB和phaC基因的纤维细胞质中存在电子透明颗粒。纤维中66%的聚羟基丁酸分子量在0.6 × 10（6）~ 1.8 × 10（6）Da之间，聚羟基丁酸颗粒的存在导致纤维的热性能发生明显变化，纤维表现出更好的隔热性能。转基因棉花纤维的热吸收和冷却速率较慢，从而导致更高的热容。这些数据表明，棉花中的代谢途径工程可以通过引入来自其他遗传来源的新性状来增强纤维特性。这是为纺织工业生产新一代纤维的重要一步。
Alcaligenes eutrophus genes encoding the enzymes, beta-ketothiolase (phaA), acetoacetyl-CoA reductase (phaB), and polyhydroxyalkanoate synthase (phaC) catalyze the production of aliphatic polyester poly-D-(-)-3-hydroxybutyrate (PHB) from acetyl-CoA. PHB is a thermoplastic polymer that may modify fiber properties when synthesized in cotton. Endogenous beta-ketothiolase activity is present in cotton fibers, Hence cotton was transformed with engineered phaB and phaC genes by particle bombardment, and transgenic plants were selected based on marker gene, beta-glucuronidase (GUS), expression. Fibers of 10 transgenic plants expressed phaB gene, while eight plants expressed both phaB and phaC genes, Electron microscopy examination of fibers expressing both genes indicated the presence of electron-lucent granules in the cytoplasm, High pressure liquid chromatography, gas chromatography, and mass spectrometry evidence suggested that the new polymer produced in transgenic fibers is PHB. Sixty-six percent of the PHB in fibers is in the molecular mass range of 0.6 x 10(6) to 1.8 x 10(6) Da. The presence of PHB granules in transgenic fibers resulted in measurable changes of thermal properties, The fibers exhibited better insulating characteristics. The rate of heat uptake and cooling was slower in transgenic fibers, resulting in higher heat capacity, These data show that metabolic pathway engineering in cotton may enhance fiber properties by incorporating new traits from other genetic sources. This is an important step toward producing new generation fibers for the textile industry.