Molecular characterization of isolated Xanthomonas sp. from rice rhizosphere soil and their inhibition using Clerodendrum viscosum Vent.

In this study,we characterized some xanthomonas sp. from rice rhizosphere soil by 16s rdna sequence analysis and the potentiality tested of oil and extracts of clerodendrum viscosum vent. leaves against those isolated bacteria. the essential oil compositions were evaluated by gcms analysis and identified twenty four compounds as 94.37% of the total essential oil,where cyclohepta-1,3,5,-triene (16.07%),2h-1,4-pyridoxazin-3(4h)-one (12.27%),l-carvenol (8.04%),pcymene (9.15%),α-terpineol (7.98%),β-sitosterol (6.76%),tyranton (6.42%),mesityl oxide (6.34%),γ-terpinene (5.42%) and β-linalool (3.74%) were the major constituents. according to the 16s rdna sequences analysis,hb28 and xb43 isolates have shown the 100% similarity for xanthomonas retroflexus and xanthomonas theicola. in addition,isolates ha18,xb33 and jb30 also have shown the maximum similarity of 98% for xanthomonas sp. tb8-9-ii,xanthomonas campestris and xanthomonas sp. bbct38. furthermore,in vitro studies showed that the oil have the inhibitory effect on xanthomonas sp. tb8-9-ii,x. campestris,x. retroflexus,xanthomonas sp. bbct38,and x. theicola,where the zone of inhibition and mic values were 18.8 to 25.9 mm and 62.5 to 125 μg ml-1,respectively. however,organic extracts showed the zone of inhibition and mic values were 13.4 to 22.9 and 62.5 to 500 μg ml-1,respectively. our findings suggested that the essential oil and extracts of c. viscosum vent. leaves might be the effective source to control xanthomonas sp. biologically.