17 Fahima Firdouse .M Sudha .A Johnson .I Anandham .R Saranya .N Selva amala .A Arunparakash .S Journal of Animal and Plant Sciences JAPS 20242024/08/25 34 4 927-935 1018-7081 https://doi.org/10.36899/JAPS.2024.4.0777 <p><em><span lang="EN-IN">Bacterial leaf blight caused by&nbsp;</span></em><em><span lang="EN-IN">Xanthomonas oryzae</span></em><span lang="EN-IN">&nbsp;pv.&nbsp;<em>oryzae</em>&nbsp;(<em>Xoo</em>) is a catastrophic bacterial disease of rice, and researchers are facing difficulties in developing the management practices, whereas the continued use of bactericides&nbsp;<em>viz</em>, streptomycin, copper oxychloride leads to the development of resistant&nbsp;<em>Xoo</em>&nbsp;strains. As a consequence, the development of an environmentally safe bactericide for the management of this devastating disease is needed. The present study focused on identification of effective&nbsp;</span>synthetic activators&nbsp;<span lang="EN-IN">against&nbsp;<em>bacterial leaf blight in rice&nbsp;</em><em>during their interaction</em>. Survey was conducted to collect different isolates of&nbsp;<em>Xoo</em>&nbsp;and their morphological characters and biochemical properties were determined. All the 10 isolates exhibited circular to flattened slimy yellow colour colonies of the pathogen&nbsp;</span>and showed positive reaction for citrate utilization, lysine utilization and ornithine utilization test. All the ten isolates showed negative reaction for sorbitol utilization.&nbsp;<span lang="EN-IN">The collected isolates were subjected to PCR for the amplification of&nbsp;</span>16S-23S&nbsp;<span lang="EN-IN">intergenic region</span>with the&nbsp;<span lang="EN-IN">species specific primer and obtained amplicon at&nbsp;</span><span lang="EN-IN">⁓</span>470 bp&nbsp;<span lang="EN-IN">for the confirmation at molecular level.&nbsp;</span>T<span lang="EN-IN">he virulen</span>t<span lang="EN-IN">isolate w</span>as<span lang="EN-IN">identified by measuring&nbsp;</span>biofilm formation and xanthomonadin pigment which revealed that the isolate ADT 53&nbsp;<span lang="EN-IN">strain&nbsp;</span>T3 with the accession number OR121377 recorded maximum<span lang="EN-IN">OD value of&nbsp;</span>0.356 for biofilm formation at 570 nm and 0.686 for xanthomonadin pigment at 445 nm.<em>&nbsp;In planta</em> studies revealed that salicylic acid at 100 ppm has the maximum inhibitory effect against bacterial leaf blight disease with the minimal lesion size of 0.7 cmcompared to negative control (water).</p> Keywords : Activators, BLB , Biofilm, Characterization, In planta, Xanthomonadin Pakistan Agricultural Scientists Forum https://thejaps.org.pk/AbstractView.aspx?mid=2023-JAPS-1155