African Journal of Biotechnology Vol. 2 (2), pp. 26–32, February 2003

ISSN 1684-5315  © 2003 Academic Journals  

MINIREVIEW

The molecular initiation and subsequent acquisition of disease resistance in plants

Emma Wanjiru Gachomo¹, Olusola Olusoji Shonukan² and Simeon Oloni Kotchoni^{3 *}

¹Institute for Plant Diseases, Nussallee 9, University of Bonn, D-53115 Germany.

²Department of Microbiology, Obafemi Awolowo University, Ile-Ife, Nigeria.

*Corresponding author; Tel: +49-228739580, Fax: +49-228732689, E-mail: 

kotchoni@uni-bonn.de

Accepted 16 January, 2003

Interactions between disease resistance (R) genes in plants and their corresponding pathogen avirulence (Avr) genes are the key determinants of whether a plant is susceptible or resistance to a pathogen attack. Evidence has emerged that these gene-for-gene interactions in the perception of pathogenic invasions and development of acquired resistance in plants involve different molecular and hormonal transduction pathways, which are still poorly understood. It has become apparent that plants actively produce several phytohormones such as ethylene, jasmonate, salicylic acid, and reactive oxygen intermediates prior to upregulation of R genes. The physiological role of these molecules in plant resistance to pathogens is beginning to attract attention. The use of transgenic plants in recent attempts, including development of mutants with altered R genes, has provided new insights into the mechanisms involved in pathogen perception, signal transduction and subsequent resistance to disease in plants. This review tries to summarize current knowledge of pathogen-related genes in plants, and how they can be use to improve disease resistance in agronomically valuable plants. It also describes the molecular basis of defense mechanisms in plants under pathogen attack.

Key words: Avr, resistance gene, hypersensitivity, pathogenesis-related proteins, transgenic, plant-defense.