Austin S, Bingham E T, Koegel R G, Mathews D E, Shahan M N, Straub R J, Burgess R R
Biotechnology Center, University of Wisconsin-Madison, 53706.
Ann N Y Acad Sci. 1994 May 2;721:234-44. doi: 10.1111/j.1749-6632.1994.tb47395.x.
The overall aims of the research are to develop genetically engineered alfalfa producing high levels of industrially important enzymes and to develop rapid methods for extracting and purifying these enzymes from alfalfa juice. Using a reporter gene beta-glucuronidase (GUS) as a model system, we were able to demonstrate production of a foreign protein in alfalfa and gain valuable insight into the molecular approaches required for the expression and accumulation of foreign proteins in leaf tissue. GUS activity varied among individual transformants, and GUS was expressed in all plant tissues. GUS activity was shown to segregate in sexual progeny. There was no correlation between copy number of the GUS gene and activity. We have recently demonstrated the production of Mn-dependent lignin peroxidase and alpha-amylase in transgenic alfalfa. Concurrent research in the agricultural engineering aspects of this feasibility study focused on extraction strategies for the recovery of alfalfa juice, and on an evaluation of methods for processing and concentrating the juice. Thus, we are in a position to use plants expressing enzymes that have current or potential industrial importance to complete a feasibility study, and determine whether we can indeed economically recover target enzymes from field-grown transgenic alfalfa plants. The technology developed for these enzymes can be used to extract other value-added products from plants in the future.
该研究的总体目标是培育出能产生大量具有重要工业价值酶的基因工程紫花苜蓿，并开发从紫花苜蓿汁液中提取和纯化这些酶的快速方法。以报告基因β-葡萄糖醛酸酶（GUS）作为模型系统，我们能够证明在紫花苜蓿中产生了外源蛋白，并深入了解了在叶片组织中表达和积累外源蛋白所需的分子方法。GUS活性在各个转化体之间存在差异，并且GUS在所有植物组织中均有表达。结果表明，GUS活性在有性后代中发生分离。GUS基因的拷贝数与活性之间没有相关性。我们最近已证明在转基因紫花苜蓿中产生了锰依赖性木质素过氧化物酶和α-淀粉酶。这项可行性研究在农业工程方面的同步研究重点在于紫花苜蓿汁液回收的提取策略，以及对汁液加工和浓缩方法的评估。因此，我们有能力利用表达具有当前或潜在工业重要性酶的植物来完成一项可行性研究，并确定我们是否真的能够从田间种植的转基因紫花苜蓿植株中经济地回收目标酶。为这些酶开发的技术将来可用于从植物中提取其他增值产品。
