Isolation and morphological characterization of novel bacterial Endophytes from Citrus and evaluation for antifungal potential against Alternaria solani

Endophytes have always been a topic of interest for researchers due to their wide variety of benefits to their hosts and their diversity of geographical distribution. In this study, bacterial endophytes were isolated from the leaf midrib of different varieties of citrus cultivated in the Sargodha region of Punjab Pakistan. The endophytic bacterial community associated with citrus was characterized and screened for antifungal activity against Alternaria solani which causes losses to crops. A total of twelve strains were identified based on morphological and biochemical tests following Bergey’s manual of systematic bacteriology. The antagonistic potential of bacterial endophytes to A. solani was explored using the agar absorption method. This study showed the antifungal potential of Pantoea sp. (35.66%), Ensifer adhaerens (35.33%), Citrobacter diversus (33.03%), and Azotobacter nigricans (31.56%) to check the growth of pathogenic fungi compared to controls. Aureobacterium liquifaciens (27.66%), Acinetobacter sp. (25.66%), Bordetella pertussis (26.63%) also showed equal potential for inhibition. In contrast remaining isolates Enterobacter cloacae (19.33%), Azomonas agilis (17%) and Kurthia sp. (19%) were less efficient as compared to the others. Bacterial endophytes are colonized inside plants and have antagonistic potential for fungal pathogens. These endophytes should be further explored for disease control. Ongoing study in this area will help to the innovate biological control of plant pathogenic fungi