Molecular basis of disease resistance in cereal crops: An overview

Abstract

Deep insight into the molecular mechanism of disease resistance in plants is essential for devising sophisticated breeding strategies leading towards crop protection. Most of the disease resistance (R) genes show genetic and structural similarity even though their target pathogens are extremely diverged in strain types, mode of action, virulence and target plant part. The search for a unified model operating for disease resistance in cereals may provide improved control of devastating pathogens which is critical for global food security. A super family of 'R' genes encoding NBS-LRR (Nucleotide binding site- Leucine rich repeats) with its several sub-classes, recently identified ABC (ATP binding cassette) transporter and kinase START genes confer resistance to numerous pathogens. These molecular motifs activate a wide array of metabolic responses under tight genetic control as the plant detects a prospective invader. Some of the 'R' genes require additional genes for the expression of resistance. Investigations into the structure of 'R' genes, protein products, their location and mechanism of interaction with pathogen elicitor molecules and future prospects are discussed in this review.