B. thuringiensis is a Poor Colonist of Leaf Surfaces (original) (raw)
Related papers
Immigration of Bacillus thuringiensis to bean leaves from soil inoculum or distal plant parts
Journal of Applied Microbiology, 2007
Aims: We addressed the process of immigration of Bacillus thuringiensis from soil to leaves and its capacity to grow on bean diffusate medium (BDM), a medium designed to simulate the nutrient composition of the phylloplane. Methods and Results: Two different B. thuringiensis strains were inoculated into soils, onto seeds or onto lower leaves of bean plants to determine if they were able to disperse to upper leaves under controlled conditions. While B. thuringiensis isolates were commonly recovered from leaves exposed to such inocula, populations were very low (<10 CFU cm )2 of leaf). In addition, the number of cells of B. thuringiensis recovered decreased with increasing distance from the soil or from the inoculated leaves. Moreover, B. thuringiensis colonies did not grow well on BDM.
Translocation and insecticidal activity of Bacillus thuringiensis living inside of plants
Microbial Biotechnology, 2009
The major biological pesticide for the control of insect infestations of crops, Bacillus thuringiensis was found to be present naturally within cotton plants from fields that had never been treated with commercial formulations of this bacterium. The ability of B. thuringiensis to colonize plants as an endophyte was further established by the introduction of a strain marked by production of green fluorescent protein (GFP). After inoculation of this preparation close to the roots of cotton and cabbage seedlings, GFP-marked bacteria could be re-isolated from all parts of the plant, having entered the roots and migrated through the xylem. Leaves taken from the treated plants were able to cause toxicity when fed to the Lepidoptera Spodoptera frugiperda (cotton) and Plutella xylostella (cabbage). These results open up new horizons for understanding the natural ecology and evolution of B. thuringiensis and use of B. thuringiensis in insect control.
Plant and Soil, 1994
The colonizing ability of a transcipient strain of Bacillus megaterium carrying a lepidopteran-specific crylA (a) gene of Bacillus thuringiensis in the phyllospheres of various economically important plants was studied. Similar experiments were also carried out using the parental B. thuringiensis var. kurstaki strain HD 1 for a comparison.While the transcipient remained on the leaves of cotton and okra for more than 28 days, its survival in phyllospheres of mulberry, peanut, chickpea, tomato and rice was rather limited to about 3 -5 days. The persistence of B. thuringiensis, on the other hand, was extremely short (i.e. less than 4 days) on all the crop plants tested.
Annals of Microbiology, 2007
The entomopathogenic bacteriumBacillus thuringiensis is widely used for the control of many agricultural insect pests and vectors of human diseases. Several studies reported also on its antibacterial and antifungal activities. However, to our knowledge there were no studies dealing with its capacity to act as a plant growth promoting bacterium. This review surveys the potential ofB. thuringiensis as a polyvalent biocontrol agent, a biostimulator and biofertiliser bacterium that could promote the plant growth. Also, discussed is the safety ofB. thuringiensis as a bacterium phylogenetically related toBacillus cereus the opportunistic human pathogen andBacillus anthracis, the etiological agent of anthrax.
Occurrence of Bacillus thuringiensis on Cured Tobacco Leaves
Current Microbiology, 2000
A worldwide survey was conducted to evaluate the frequency and distribution of Bacillus thuringiensis populations on cured tobacco leaves during post-harvest storage. In total, 133 tobacco samples of different types and origins were analyzed. Nine percent of the samples showed the presence of B. thuringiensis, and 24 B. thuringiensis strains were isolated and characterized. The majority of the isolates produced bipyramidal crystals, and three fourths of them showed a second type of crystal protein (cuboidal or heterogeneous crystals). Only three isolates showed the rhomboidal crystal morphology characteristic of the anti-coleopteran B. thuringiensis subsp. tenebrionis. PCR analysis with primers specific for cry1 and cry3 genes revealed eight distinct cry gene profiles. The results of this study indicate that B. thuringiensis is naturally present at low frequency on the phylloplane of cured tobacco leaves and that its distribution is worldwide.
The colonization of Bacillus thuringiensis strains in bryophytes
TURKISH JOURNAL OF BIOLOGY, 2017
In our previous study, several Bacillus thuringiensis (Bt) strains were isolated from bryophyte samples, indicating that bryophytes could serve as Bt reservoirs in the wild. SFR13 is a wild strain isolated from the bryophyta Physcomitrium japonicum. In order to understand its ecological properties, green fluorescent protein (GFP)-labelled SFR13 (SFR13GFP) was generated to evaluate the colonization capability in bryophytes, using dynamic tracing and cell counting to observe the process and patterns of colonization. Our results showed that genetic stability, growth curve dynamics, and insecticidal crystal production were not affected by GFP expression in Bt. Fluorescence microscopy was used to track the dynamic distribution of SFR13GFP. Distribution patterns showed that SFR13GFP can establish stable and long-term colonization in leaves and stems by the 26th day after inoculation. A better understanding of how Bt colonizes plants in the wild will not only result in increased knowledge of plant-microbe interactions but will also lead to a more successful and reliable use of bacterial inoculants.
Natural occurrence of Bacillus thuringiensis on grass foliage
World Journal of Microbiology & Biotechnology, 1998
Bacillus thuringiensis isolates were naturally present on the phylloplane of grass foliage collected from a pasture ®eld at Wageningen in The Netherlands. Characterization of 32 isolates from foliage showed that 75% belonged to serovar israelensis (H-14). A few other serovars were also found (indiana, japonensis, nigeriensis and pakistani). In toxicity tests, 84% of the isolates showed larvicidal activity against Aedes aegypti, whereas no activity against Pieris brassicae was detected in any of the isolates. Activity against Tipula oleracea was documented for a few isolates of serovar israelensis.
Jundishapur Journal of Microbiology, 2015
Background: Bacillus thuringiensis is the most successful biological control agent, however, studies so far have shown that B. thuringiensis is very sensitive to environmental factors such as soil moisture and pH. Ultraviolet light from the sun had been considered as the main limiting factor for its persistence in soil and it has recently been shown that the antagonism exerted by other native soil organisms, such as Pseudomonas fluorescens, is a determining factor in the persistence of this bacterium under in vitro culture conditions. Objectives: The aim of the present investigation was to analyze the population dynamics of B. thuringiensis and its interaction with P. fluorescens using microbiological and molecular methods in soil, under different conditions, and to determinate the effect of nutrients and moisture on its interaction. Materials and Methods: The monitoring was performed by microbiological methods, such as viable count of bacteria, and molecular methods such as Polymerase Chain Reaction (PCR) and hybridization, using the direct extraction of DNA from populations of inoculated soil. Results: The analysis of the interaction between B. thuringiensis and P. fluorescens in soil indicated that the disappearance of B. thuringiensis IPS82 is not dependent on the moisture but the composition of nutrients that may be affecting the secretion of toxic compounds in the environment of P. fluorescens. The results showed that the recovered cells were mostly spores and not vegetative cells in all proved treatments. The molecular methods were effective for monitoring bacterial population inoculated in soil. Conclusions: Bacillus thuringiensis is very sensitive to the interaction of P. fluorescens, however is capable to survive in soil due to its capacity of sporulate. Some of the cells in the form of spores germinated and folded slightly and remained in a constant cycle of sporulation and germination. This confirms that B. thuringiensis IPS82 can germinate, grow and sporulate in soil.