Overexpression of a Bacterial Chitinase Gene in Plants: A Novel Approach to Disease Tolerance

在第一阶段的研究中，从粘质Serrata marcescens细菌中提取的几丁质酶（chiA）基因被融合到三个不同的启动子片段中。这些嵌合基因已被引入烟草原生质体。已经产生了稳定转化的植株，并且已经鉴定出在mRNA和蛋白质水平上表达高水平chiA基因的个体。这些已被测定对真菌感染的敏感性。看来他们对这种疾病的抵抗力增强了。本二期研究计划提高几丁质酶的表达水平，在特定组织（根）和细胞外表达几丁质酶。随后，该基因将被转移到其他植物上，并测试它们对其他病原体的抗性。这项实验研究将在烟草、番茄和甘蓝型油菜上进行，并将测定其对交替菌、白粉病和根球形线虫的抗性。通过植物基因工程控制多种真菌可以大大提高作物产量，并防止化学杀菌剂的过度使用。

In Phase I research the chitinase (chiA) gene from the bacterium Serrata marcescens has been fused to three different promotor fragments which have been isolated. These chimaric genes have been introduced into tobacco protoplasts. Stably transformed plants have been generated and individuals have been identified which express high levels of the chiA gene at both the mRNA and protein level. These have been assayed for susceptibility to infection by the fungus Alternaria. It appears that they exhibit an increased resistance to the disease. In this Phase II research, it is planned to improve the level of expression and to express chitinase in specific tissues (roots) and outside the cell. Later the gene will be transferred to other plants and their resistance to other pathogens will be tested. This experimental research will be performed in tobacco tomato and Brassica napus and will assay for conferred resistance against Alternaria, the powdery mildews, and root knob nematodes. Control of a broad range of fungi by genetic engineering of plants could greatly increase crop production and preclude the excessive use of chemical fungicides.