ABSTRACT
Cultures and Their Applications........................................................................ 225 7.2.3 Bioconversion of Metabolites ......................................................................................... 226
7.2.3.1 Case Study: Bioconversion of Sucrose to Its Isomer Form, Palatinose — Possible Impact on Carbohydrate Metabolism in Potato (
Solanum tuberosum
) Tubers................................................................ 228 7.3 Natural Products and Plant Biodiversity...................................................................................... 229
7.3.1 An Overview of the Status of Plant Biodiversity........................................................... 229 7.3.1.1 Uses of Wild Plants ......................................................................................... 230
7.3.2 The Biodiversity of Several Medicinal Plants in the World — Their High-Value Secondary Metabolites and Uses ................................................................ 230 7.3.2.1 St. John’s Wort (
Hypericum perforatum
L.) ................................................... 230 7.3.2.2 Hawthorn (
Crataegus
spp.).............................................................................. 231 7.3.2.3 Legumes ........................................................................................................... 232 7.3.2.4 Flax (
Linum
spp.)............................................................................................. 233 7.3.3 Different Aspects of the Exploration and Sustainable Exploitation of
Plant Biodiversity ............................................................................................................ 233 7.3.3.1 Methods for Phytochemical Screening and Testing of Biological
Activity of Plant Extracts ................................................................................ 234 7.3.3.2 Case Study: Evaluation of Extraction Efficiencies for
H. perforatum
Chemistries....................................................................................................... 234 7.3.4 Chemotaxonomy and Its Relationship to Secondary Metabolism................................. 235
7.4 Plant Cell Biotechnology for the Production of Secondary Metabolites.................................... 236 7.4.1 Factors Determining the Accumulation of Secondary Metabolites by Plant Cells....... 237 7.4.2 Plant Cell Culture as a Method for Studying Biosynthesis and the Production
of Secondary Metabolites ............................................................................................... 238 7.4.3 Strategies to Improve Metabolite Production................................................................. 239
7.4.3.1 Selection of Elite Germplasm for an Efficient Production System................ 239 7.4.4 Micromanipulation of Higher Plant Cells for Production Systems............................... 240
7.4.4.1 Elicitation ......................................................................................................... 241 7.4.4.2 Screening and Selection of Cultured Plant Cells in Order to Increase
Yields of Phytochemicals ................................................................................ 242 7.4.5 Growth and Production Kinetics of Plant Cell Cultures in Bioreactors........................ 244
7.4.5.1 Batch Systems.................................................................................................. 245
7.4.5.2 Long-Term Continuous Cultivation................................................................. 246 7.4.5.3 Large-Scale Production of Plant Secondary Metabolites in
Bioreactors ....................................................................................................... 247 7.5 Metabolic Engineering of Plant Secondary Metabolism............................................................. 247
7.5.1 Engineering of Plant Secondary Metabolite Pathways for the Production of Natural Products.............................................................................................................. 248 7.5.1.1 Increasing Total Carbon Flux through Metabolic Pathways........................... 248 7.5.1.2 Overcoming Rate-Limiting Steps .................................................................... 249 7.5.1.3 Blocking Catabolism or Competitive Pathways.............................................. 250
7.5.2 Metabolic Engineering for Plant Improvement and Protection against Environmental Stresses ................................................................................................... 250
7.6 Molecular Farming ....................................................................................................................... 251 7.6.1 Molecular Farming Is a Relatively New Area of Science and Industry........................ 251 7.6.2 Molecular Farming of Valuable Natural Products and Pharmaceutical Proteins .......... 252
7.6.2.1 Fermentation Process, Extraction, and Purification ........................................ 253 7.6.2.2 The Significance in Relation to the Plant Biotechnology............................... 254
7.7 The Benefits and Risk Factors of Biotechnology and Future Prospects .................................... 254 7.8 Conclusions .................................................................................................................................. 255 References .............................................................................................................................................. 256
Achievements today in plant biotechnology have already surpassed all previous expectations. Plant biotechnology has emerged as an exciting area of research by creating unprecedented opportunities for the manipulation of biological systems of plants. It is a forward-looking research area based on promising accomplishments in the past several decades. Plant biotechnology is changing plant science in three major areas: (1) growth and development control (vegetative, generative, and propagative), (2) protection of plants against the environmental threats of abiotic or biotic stresses, and (3) expansion of ways by which specialty foods, biochemicals, and pharmaceuticals are produced. To determine the current status of plant biotechnology, it must emphasize the difference between the traditional concept of biotechnology and its current status. Early directions of plant biotechnology, which mostly focused on
in vitro
cell and tissue culture and their production of important products, are now advancing into new directions. The current state of plant biotechnology research using a number of different approaches includes highthroughput methodologies for functional analysis at the levels of transcripts, proteins, and metabolites, and methods for genome modification by both homologous and site-specific recombination. Plant biotechnology allows for the transfer of a greater variety of genetic information in a more precise, controlled manner. The potential for improving plant productivity and their proper use in agriculture relies largely on newly developed
DNA biotechnology
and
molecular markers
. These techniques enable the selection of successful genotypes, better isolation and cloning of favorable traits, and the creation of transgenic organisms of importance to agriculture and industry.
