Journal of Plant Pathology (2002) 84, p. 176 (Boarino et al.)

A. Boarino and C. Marzachì (2002)
Identification and partial characterization of a DNA ligase gene from 16SrXII (stolbur) group phytoplasma
Journal of Plant Pathology 84 (3), 176-176
IX Meeting, Italian Society for Plant Pathology
Abstract: Phytoplasmas are wall-less phloematic prokaryotes inducing different syndromes in several plant species. They can not be maintained in axenic cultures, and this has hampered the study of their genomic organisation. To improve our knowledge on phytoplasma functional genes, databank (NCBI) bacterial gene sequences were used to construct degenerated primers for PCR amplification of partially homologous phytoplasmal sequences. One 340 bp phytoplasma specific amplicon has been obtained from 16SrXII-A subgroup phytoplasma (Stolbur) DNA, maintained in periwinkle. It has been cloned (pLig1) and sequenced. Sequence analysis with BlastN and BlastX revealed high similarity with bacterial NAD-dependent DNA ligase proteins (NAD-Lig). These are essential enzymes found in all bacteria that catalyse the formation of phosphodiester bonds at single-strand breaks between adjacent termini in double stranded DNA. Labelled pLig1 insert DNA was used to screen a Stolbur phytoplasma genomic library. One positive clone (pLig2) has been further characterised: it was 1816 bp long, partially overlapping to the 3' end of pLig1 and contained 1296 bp at the 3' end of the NAD-Lig gene. BlastX comparison of the total 1488 bp sequence confirmed the high similarity with bacterial NAD-Lig genes. RT- PCR on healthy and infected periwinkle total RNAs, with specific primers designed on Stolbur NAD-Lig specific sequence, confirmed the hypothesis of NAD-Lig gene expression in this phytoplasma.
Database assignments for author(s): Cristina Marzachi

Research topic(s) for pests/diseases/weeds:
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	16SrXII phytoplasma group