Abstract
Over 400 bacterial strains, isolated from leaf surfaces of Curcuma alismatifolia Gagnep. and hot springs in the Chiang Mai province of northern Thailand, were screened in vitro for antagonistic activity against Colletotrichum musae, an anthracnose fungus. Three isolates provided greater than 75% growth inhibition of the fungus in vitro and were identified as Bacillus licheniformis, B. amyloliquefaciens and B. subtilis. Using in planta tests, B. amyloliquefaciens and B. subtilis were shown to efficiently colonize the curcuma bracts, provide a statistically significant growth suppression of C. musae over that of B. licheniformis, and all three isolates could provide 100% inhibition of conidial fungal germination. When B. licheniformis was co-inoculated in combination with either of the other two bacteria, the ability of B. amyloliquefaciens and B. subtilis to suppress the fungal disease was dramatically reduced. Both B. amyloliquefaciens and B. subtilis were found to contain an isoform of iturin A with antifungal activity against C. musae. As a preventative measure to control the spread of C. musae and reduce the severity of fungal infections, B. amyloliquefaciens could be used to inoculate curcuma flowers cost effectively and reduce the need for the toxic synthetic fungicides currently in use.
Highlights
Curcuma (Curcuma alismatifolia Gagnep.), a species of the genus Zingiberaceae, is a decorative flower with highly variable shapes and bract colors that is an ornamental of significant economic importance for Thailand since it is regularly exported to many countries around the world including Japan, the U.S.A., the Netherlands and New Zealand
The growth inhibition of C. musae by all of the bacteria isolates was determined after a week of incubation and recorded as a decay diameter (Table 1)
After an initial screening of over 430 bacterial isolates from two different environments, the in vitro growth of C. musae was found to be markedly suppressed by three candidate bacterial species: B. licheniformis and B. amyloliquefaciens from hot springs and B. subtilis found residing on curcuma leaves
Summary
Curcuma (Curcuma alismatifolia Gagnep.), a species of the genus Zingiberaceae, is a decorative flower with highly variable shapes and bract colors that is an ornamental of significant economic importance for Thailand since it is regularly exported to many countries around the world including Japan, the U.S.A., the Netherlands and New Zealand. Symptoms of anthracnose include an initial pinpoint water-soaked spotting of the curcuma flower. These spots enlarge to approximately 3 mm in diameter and are light tan in the center with raised dark borders. On plants ready to transplant, large brown cankers can develop on the stems, and fruiting bodies called acervuli are present in affected areas. These acervuli produce pink spore masses and may have black bristle-like appendages called setae. Conidia can present as cylindrical to oblong protrusions while the mature spines show a standard sticklike form, which erupts over the outer epidermal cell wall of the host
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: American Journal of Agricultural and Biological Sciences
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
