Biotechnological strategies for engineering plants with durable resistance to fungal and bacterial pathogens
Publisher Summary Fungal and bacterial pathogens are a major threat to the yield of crop plants worldwide. Therefore, an important goal in plant science is the production of plants with broad-spectrum and durable resistance to microbial diseases. Potential strategies to reach this goal include classical or marker-assisted breeding and genetic engineering. This chapter reviews critical issues that should be considered in the design of transgenic technologies for durable and broad-spectrum resistance. Custom-made combinations of promoters and transgenes may be designed and tested for disease control. The focus of this discussion is on the choice of target genes to be expressed, on the number of genes to be employed, and on the control of their expression. Type and number of transgene(s), and the native or synthetic promoter(s) to be employed should be carefully selected according to the desired spectrum of disease resistance (narrow or broad), the nature (bacteria, fungi, or both), lifestyle (biotrophic or necrotrophic) and virulence strategies of the pathogens(s), and the genetic and physiological characteristics of the engineered crop. The efficient plant immune system relies both on preformed structural and chemical barriers, and on inducible defense responses that are activated by complex mechanisms of molecular recognition and cellular signal transduction.