Insights on phytoplasma genomics and host-pathogen interaction

Phytoplasma research started since the discovery of these fascinating phytopathogenic organisms as bacteria in 1967. The knowledge increased dramatically in the fields of detection, classification, genome sequencing and host plant response owing to recent advances in molecular techniques. A major breakthrough was made by deciphering the complete genomes of four phytoplasma strains, providing the insights into the genetics of these bacteria with comparative genome study. Although gene order is not conserved among different phytoplasma strains, synteny was observed between closely related phytoplasmas. The comparative analysis of phytoplasma genomes has also increased understanding of their metabolic capabilities. Ever since some essential metabolic pathways are completely lacking and others are greatly reduced, it is still difficult to draw a clear picture about the regulation of metabolic processes. However, efforts for sequencing of other phytoplasma genomes from diverse taxons is a need to provide insights into the organism's biology and to discover genes that could be related to biological properties and specificity to diverse plant species. Some efforts in last decade had been made to decipher the host responses at biochemical, genomics, proteomics and metabolomic levels for understanding the host-pathogen interactions however more concentrated efforts in this regards needs to be emphasized.