An Introduction
Biotechnology can be seen as an imprecise term since the harnessing of any biological process could justifiably be called biotechnology. In food processing it could reasonably be applied to processes as long established as bread making and brewing. However, the revolution in our understanding of the molecular mechanisms underlying the processes of life, in particular our understanding of DNA, has resulted in the potential to manipulate those mechanisms for our requirements. This new-found knowledge and ability is loosely termed biotechnology.
There are two main applications of biotechnology to fruit and vegetable production:
- as an aid to conventional breeding programmes
- its ability to transfer genes between different organisms.
Physiological or morphological traits are governed by genes carried on chromosomes. The ability to monitor the presence or absence of such genes in plants is a great aid to plant breeders. This is done through the use of molecular markers, characteristic DNA sequences or fragments that are closely linked to the gene or genes in question. Molecular biological methods allowing
the monitoring of such markers in many independent individuals, for example those arising from a cross between two plant varieties. This is a great aid to the selection process.
The ability to transfer genes means that specific genes can be added to a crop variety in one step, avoiding all the back-crossing that is normally required, providing a major saving of time and effort. Furthermore, those genes that are added need not come from a species that is sexually compatible with the crop in question. Conventional breeding is, of course, limited to the introduction of genes from plants of the same species or very near relatives. By employing the science of genetic engineering, it is possible to bring into a crop plant different genes from other plants or even bacteria, fungi or animals. Genes are, simplistically, made up of two parts: the coding region which determines what the gene product is, and the promoter, a set of instructions specifying where,
when and to what degree a gene is expressed. Coding regions and promoters from different genes can be spliced together in the laboratory to provide genes with new and useful properties (recombinant DNA). These foreign or recombinant genes can then be introduced back into crop plants through the techniques of plant genetic transformation. The introduced genes integrate into
the plant genome and will be passed on to the offspring in the normal way. In this way it is possible to enhance existing characteristics and introduce new attributes into a crop.
This entire section explores the application of biotechnology in this second area of fruit and vegetable cultivation and their subsequent use in food processing.
Tools of genetic engineering in plants section describes the basic tools and methods of genetic manipulation, from the selection and isolation of genes to safety issues such as the stability of transgenes. Initial parts of the preceeding sections then considers the range of target properties for genetic enhancement, starting with two sections on how biotechnology can improve quality and productivity in fruit and vegetable cultivation.
Genetic modification of agronomic traits in fruit crops section looks at the genetic modification of agronomic traits in fruit crops such as herbicide resistance, resistance to plant pests and environmental stresses, increasing yield and fruit quality.
Genes involved in plant defence mechanisms section looks in more detail at improving plant defences against pathogens. A group of three sections then discusses the enhancement of traits which affect final product quality.
Genes selected for their role in modifying post-harvest life section considers how biotechnology can help in extending the post-harvest life of fruit and vegetables, an increasingly important issue given the complexity of modern supply chains. Section
The use of molecular genetics to improve food properties reviews the use of molecular genetics to improve food properties such
as nutritional quality and sensory characteristics such as colour and flavour. Given its importance,
Nutritional enhancement of plant foods section looks in more detail at the nutritional enhancement of plant foods.
Some later sections includes three case studies on the application of biotechnology to particular crops. Tomato was the subject of the first commercial release of a transgenic food product, the Flavt Savr tomato with extended shelf life of the ripe fruit, and has subsequently been a particular focus for research in this field. Section titlec
Tomato reviews the range of work done on that vegetable (fruit).
Commercial developments with transgenic potato section considers current commercial developments with transgenic potato whilst
Cucurbits, pepper, eggplant, legumes and other vegetables section reviews work on a range of other vegetables and fruit from melon and cucumber to cabbage, broccoli, cauliflower and lettuce. Finally,
Consumer's attitudes and
Risk assessment looks at the all-important issues of consumer attitudes and risk assessment, with sections on these issues and identifying GMOs in foods.
