Promoter is a DNA sequence that regulates the expression of a particular gene. They are classified on the basis of their function and spatio-temporal expression into constitutive, tissue-specific or development-stage-specific and inducible promoters. Plant genes associated with defence responses are activated by stress-factors and these genes are known to be regulated by promoters or the upstream elements. Promoters induced by abiotic stress factors in plants are fairly well studied compared to biotic stresses. This review presented information generated on promoters and regulatory elements involved in defence gene expression due to insect damage, pathogen and nematode attack to crop plants, mechanism and their utilization in crop improvement through genetic engineering.

Summary. -Clerodendron inerme, a common hedge plant grown in India, is affected by a yellow mosaic disease caused by a begomovirus. In the present study, the complete genome (DNA A) of this virus was cloned and sequenced.