-By Kranti Karande
Phytoplasma is a group of extremely small bacteria. They don’t have a cell wall and any particular shape. Phytoplasma was first identified by a Japanese scientist Yoji Doi as ‘mycoplasma-like-organisms’ in 1967. They are bacterial parasites of plants and insects.
Sugarcane Grassy Shoot (SCGS) is a disease caused by phytoplasma and the disease leads to 5% to 20% crop loss. SCGS phytoplasma causes severe proliferation of tillers leading to the typical grassy appearance of sugarcane, hence the name grassy shoot is given. Another disease called Bermuda Grass White leaf (BGWL) disease is a destructive phytoplasma disease of Bermuda grass.
Research group of Dr. Amit Yadav at NCMR, NCCS Pune performed whole genome sequencing of two phytoplasma associated with these two diseases. This is the first whole genome sequence of phytoplasma published from India. This sequence data might help in taxonomical characterization of other phytoplasma belonging to the same group.
A sugarcane plant sample (strain SCGS) exhibiting grassy shoot symptoms and a Bermuda grass sample (strain LW01) showing white leaf symptoms were collected from Pune, Maharashtra, India. The presence of phytoplasma was confirmed by 16S rRNA gene sequencing. Researcher confirmed that these phytoplasma strains belonged to the 16SrXI and 16SrXIV phytoplasma groups, respectively. Both genomes were annotated using the NCBI Prokaryotic Genome Annotation Pipeline
The final SCGS assembly contained 29 scaffolds corresponding to 505,173 base pairs of DNA. The genome was found to be 95.43% complete and the GC content was 19.86%.The SCGS genome was predicted to have 404 protein-coding genes, 12 tRNA and two rRNA genes.
Similarly, the LW01 assembly contained 21 scaffolds corresponding to 483,935 base pairs of DNA. This genome was found to be 91.32 % complete and the GC content was 20.46 %. The LW01 genome was predicted to have 425 protein-coding genes, 13 tRNA and three rRNA genes.