Plant biotechnology in agriculture

Abstract

Knowledge on plant genomes has progressed during the past few years. Two plant genomes, those of Arabidopsis thaliana and rice, have been sequenced. Our present knowledge of synteny also indicates that, despite plasticity contributing to the diversity of the plant genomes, the organization of genes is conserved within large sections of chromosomes. In parallel, novel plant transformation systems have been proposed, notably with regard to plastid transformation and the removal of selectable marker genes in transgenic plants. Furthermore, a number of recent works considerably widen the potential of plant biotechnology.

Introduction

Prior to agriculture, humans lived as nomadic hunters and could survive solely on wild plant and animal resources. Noticing the immense wealth of the plant and animal kingdoms, their successful efforts to domesticate the wild species launched agriculture. Until very recently, plant breeding still relied solely on the accumulated experience of generations of farmers and breeders, that is, on sexual transfer of genes between plant species. However, recent developments in plant molecular biology and genomics now give us access to the knowledge and understanding of plant genomes and even the possibility of modifying them. Plant geneticists have adopted Arabidopsis thaliana as a model organism some years ago because of its small diploid genome (the Arabidopsis genome, at about 120 Mb, is amongst the smallest known plant genomes), low repetitive DNA content, and rapid reproductive rate. Now, the complete sequence of the genome of this plant is known, which will lead to the identification of all its 26,000 genes [1]. Based on this success, the sequencing of various cultivated plant genomes is now well underway (e.g. rice). The rice genome sequence provides a foundation for the improvement of cereals, our most important crops [2], [3]. Most importantly, our present knowledge of synteny indicates that, despite plasticity contributing to the diversity of the plant genomes, the organization of genes is conserved within large sections of chromosomes [4], [5], [6], [7], [8]. This validates a posteriori the considerable efforts made on model species. Such progress has encouraged a massive surge in plant biotechnology, which is currently changing our vision of crop production and protection. Indeed, this technological progress enables us to insert useful genes into cultivated plants at an incomparably fast rate and, doubtless, in a much more precise manner than with conventional genetic methods.