Plant pathogen interactions: crop improvement under adverse conditions

Abstract

Alleviating the crop loss due to biotic stress is the primary aim of plant biologists to achieve sustainable evergreen revolution in order to feed rapidly growing population. In nature, continuous evolution of plants while interacting with pathogens has generated a complex immune system that consists of preformed barriers and induced responses. The induced responses are further subdivided based upon the recognition of microbe-associated molecular patterns and effectors produced by pathogens; however, overlap exists between the downstream signaling pathways. In last decade, great deal of information about molecular aspects of plant–pathogen interactions has been generated which can be utilized for improving crops through genetic manipulation. Plant breeding has helped in the isolation of species-specific resistance components (R genes) from many plants. The molecular breeding techniques have also helped in pyramiding several components to a single variety, especially QTLs responsible for plant resistance, high yield, and nutritional quality. The identification of nonhost components in model plants and incorporation of genetically modified crops in our cropping system have raised hopes that nonhost resistance can be utilized for generating broad-spectrum pathogen tolerance breaking the barriers of species level resistance. This chapter describes the recent molecular aspects of plant–pathogen interactions focusing on the nonhost resistance components. Additionally, strategies like specific regulation of induced defense responses, manipulation of susceptibility factors, and host-induced gene silencing (HIGS) are discussed. The development of GM crops using such strategies will help in generating higher yields against pathogen infestations.