Thuja orientalis L. (Cupressaceae) is an evergreen ornamental garden plant. Its medicinal value is also a well known fact in the literature. The larvae of the evergreen bagworm Thyridopteryx ephemeraeformis feed voraciously on the green foliage of Thuja orientalis and construct protective bags by fastening the eaten up branches of the plant together with silk secreted by the larvae. Brown elongated bags are frequently observed hanging from the branches. Plants usually are completely defoliated and weakened that deteriorates their ornamental as well as medicinal value and it becomes a great concern to the gardener.
Background: Bacteria communicate with each other via chemical signals to coordinate expression of specific genes in a cell density dependent fashion a phenomenon called quorum sensing and response. Pseudomonads are ubiquitous bacteria that are common inhabitants of rhizosphere; these stimulate plant growth by facilitating either uptake of nutrients from soil or producing certain plant growth promoting substances. Besides, these bacteria also prevent proliferation of phytopathogens and thereby support plant growth.
Challenges: The present study deals with the quorum sensing mechanism which influences the antifungal activity of Pseudomonas aeruginosa and Pseudomonas fluorescens strains against the Rhizoctonia solani. The antifungal activity of the Pseudomonas aeruginosa and its extract was tested. The plant growth promoting ability was then analyzed and compared. Seed germination assay was also performed for proving quorum sensing.
Conclusion: Quorum Sensing in Biocontrol and Plant Growth Promoting Properties of Pseudomonas sp. was evaluated and found to be satisfactory.
Background: Aspergillus spp. is an important cause of food degradation and biodeterioration, in addition to being pathogenic to animals. Moreover, some species are used in biotechnology and can produce mycotoxins. This paper reports the use of CREA compounds combined with three alternative pH indicators for the Aspergillus systematics. CREA was added to the basal medium with different pH indicator combinations (bromocresol green and bromothymol blue).
Results: Among the 16 Aspergillus isolates, no difference was observed in the three conditions tested in CREA medium, using different pH indicators. A. ostianus, A. sydowii and Aspergillus sp showed good growth and sporulation. Aspergillus niger 1 and A. niger 2 reacted within three days of growth. As for A. carbonariuns and A. nidulans, they reacted in 5 days. Additionally, Aspergillus sp showed a delayed reaction on the tenth day. When considering the intensity relation of the reaction among the five positive isolates, A. niger 1 and A. niger 2 presented a larger and distinct zone around the colony.
Conclusion: Bromocresol green and bromothymol blue are easy to prepare, and they are recommended for diagnostic purposes in Aspergillus, specially the Nigri section.