Molecular Detection of Xanthomonas citri subsp malvacearum in Cotton Seeds

Bacterial blight of cotton caused by Xanthomonas citri subsp. malvacearum is an important bacterial disease, ubiquitous in its occurrence and is known to cause a heavy economic loss. In the present study, 30 cotton seed samples from those affected areas were screened for the presence of the bacterial blight pathogen. Recently the disease has been reported in the Karnataka state causing losses of economic significance. 12 bacterial isolates were identified based on the morphological, biochemical and molecular tests developed with ITS primers revealing the presence of the pathogen. The molecular detection using ITS primers revealed the amplification of the DNA in all the isolates thus confirming the identity of the pathogen. The PCR product of 400 bp was obtained in all the screened isolates. Random amplified polymorphic DNA (RAPD) technique was used to study and further characterise among the isolates by using OPS-12, OPS-17, OPB-4 and OPF-6 primers. Primers OPS-17 and OPF-6 were found to give better molecular variations among the 12 isolates of X. citri subsp. malvacearum. Application of these molecular, tools in the characterization of X. citri subsp. malvacearum is discussed in the present study.