Exploring Entagonistic Effect of Endophytic Microorganisms Against Xanthomonas axonopodis pv. dieffenbachiae (McCulloch & Pirone) Vauterin Causing Bacterial Blight of Anthurium

One of the major constraint in anthurium cut flower production is bacterial blight incited by Xanthomonas axonopodis pv. Dieffenbachiae (Xad). It causes considerable economic loss. Considering the serious nature of the disease the present investigation was undertaken to harness the potential of antagonistic endophytes against bacterial blight pathogen. Endophytic microorganisms were isolated from healthy anthurium plants collected from different locations. A quantitative estimation of endophytic micro organisms revealed the abundance of bacteria than fungi. Moreover, more number of endophytes were isolated from roots than from petiole and leaves. Based on cultural characters of endophytic microorganisms, 14 fungal and 37 bacterial endophytes were selected. Antagonistic action of these endophytes against pathogen was studied in comparison with that of reference culture of Pseudomonas fluorescens (KAU), P. fluorescens (TNAU), Trichoderma viride (KAU) and T. harzianum (IISR). The study revealed that, only eight bacterial and two fungal cultures showed antagonistic action against the pathogen. Since fungal endophytes showed less inhibition, they were not selected for further studies. The selected endophytes were subjected to various tests for understanding parameters that may act to produce antagonism as well as enhanced growth of the plants. All the antagonists inhibited growth of the pathogen, promoted plant growth, produced IAA and ammonia. Only two isolates viz., EB-14 and EB-31 are found cyanogenic. Only four isolates viz., EB-15, EB-31, EB-26 and EB-12 were found capable of solubilizing phosphate. All isolates except EB-12 were found capable of producing siderophores.

EB-14 and EB-31 were found cyanogenic. EB-15, EB-31, EB-26 and EB-12 were capable of solubilizing phosphate. All isolates except EB-12 were producing siderophores.