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ISOLATION AND
CHARACTERIZATION OF RALSTONIA SOLANACEARUM FROM INFECTED TOMATO
PLANTS OF SOAN SKESAR VALLEY OF PUNJAB
ZUBEDA CHAUDHRY1
AND HAMID RASHID2*
Abstract:
The most devastating
disease of tomato is bacterial wilt (BW) caused by Ralstonia solanacearum
which occur in hot and humid areas of Pakistan. Control of bacterial
wilt is difficult, because the pathogen is soil-borne and has a wide
host range. There is a need to establish resistance against this
pathogen through biotechnological approaches. As a first step, infected
tomato leaf samples were collected from various parts of soan skesar
valley of Punjab, Pakistan. Isolations were performed on triphenyl
tetrazolium salt (TTC) medium. Five samples, each of ten plants, from
seven fields were used for isolation. Bacteria with similar
characteristics were isolated from all positive samples which produced
fluidal colonies that were either entirely white or white with red
centre after incubation for 48 hours at 28oC on TTC medium.
They were found positive for gram staining, KOH test, Kovacs oxidase
test, Catalase test, Oxidation/fermentation of glucose, Hydrolysis of
tween 80 and negative for Arginine dihydrolase, Levan production, Salt
tolerance, Lecithinase detection, Gelatin hydrolysis and production of
Fluorescent pigment. Wilting and necrosis were observed for
pathogenicity test and chlorosis/necrosis was observed for
hypersensitivity. Isolates were identified as Ralstonia Solanacearum.
. Out of 10 diseased plants, 7 were found positive and 3 were negative.
1Department of Botany, Hazara University, Mansehra, KPK, Pakistan.
2Department of Bioinformatics, Mohammad Ali Jinnah University, Islamabad,
Pakistan
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