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Isolation and characterization of bacteria associated with the peach fruit fly, Bactrocera zonata (Saunders) and its role in management

KrishiKosh

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Title Isolation and characterization of bacteria associated with the peach fruit fly, Bactrocera zonata (Saunders) and its role in management
Ph.D.
 
Creator REDDY P, KRISHNA
 
Contributor Sharma, Kirti
 
Subject economic systems, biological phenomena, livestock, productivity, animal husbandry, group communication, markets, participation, marketing, policies
 
Description Tephritids, commonly known as “fruit flies” are considered as important
agricultural and horticultural crop pests. The peach fruit fly, Bactrocera zonata, is one
of the most destructive pests of more than 50 fruit crops and distributed throughout the
tropic and sub-tropics of the world. Many pest-control strategies employed are not
economically effective which resulted in significant losses; thus, a novel control
technique targeting both sexes is much needed. Symbiotic relationships between
tephritids and its gut symbiotic bacteria have been studied with few genera Anastrepha,
Bactrocera, Ceratitis and Rhagoletis. Using the culture dependent and 16S rRNA
technique, 13 culturable bacteria were isolated, characterized and identified separately
for laboratory reared (LR) and field collected (FC) adult flies of B. zonata. The bacterial
species viz., S. maltophilia, E. cloacae and K. pneumoniae were present in both LR and
FC adult flies, while B. cereus, B. subtilis, B. thuringiensis, Enterobacter sp. and
Klebsiella sp. were isolated only in FC flies although E. asburiae and Enterobacter sp.
were specific to LR flies. Transmission Electron Microscope (TEM) micrograph of
midgut content of B. zonata indicated the presence of bacteria with varied form and
shape within the gut. On the basis of 16S rRNA and PCR-DGGE, sequenced data were
affiliated to the 4 bacterial phyla viz., Gammaproteobacteria, Firmicutes, Actinobacteria,
Alphaproteobacteria and few others to unidentified organism. The bacteria Lactobacillus
plantarum, L. brevis, Serratia sp., Salmonella sp., uncultured Shigella sp., uncultured
Bifidobacterium were found both in the LR and FC flies. Interestingly, Citrobacter sp
and Commensalibacter sp were detected only in the LR flies whereas Vagococcus sp
was detected only in FC flies. PLFA analysis revealed the dominance of gram-negative
bacteria in the gut of both LR and FC adults of B. zonata. Seven different antibiotics
impregnated discs were screened against ten bacterial culture plates and found
kanamycin, streptomycin, chloramphenicol and tetracycline to be highly sensitive.
Different antibiotics incorporated at lower concentrations (5 to 20 ppm) in maggot diet
did not exhibit any negative effect on survival, development and fecundity of B. zonata
compared to 50, 100 and 200 ppm, while 30-40 ppm had intermediary effects. The
bacterial colony forming units (CFU‟s) of unsterilized eggs, surface sterilized eggs,
seven days old maggots, diet before inoculation and unconsumed diet after rearing
varied in different antibiotics treatments. Bacterial CFU‟s inhibition was stronger in
tetracycline compared to other antibiotics. The six bacterial filterates were studied in
rearing and olfactory cages for their attraction potential against female and male flies of
B. zonata. The bacterium E. cloacae and K. pneumoniae were the most attractive as
compared to S. maltophilia, E. asburiae, B. subtilis and B. cereus. The mean attraction
of flies in olfactory cage was higher compared to rearing cage. The protein starved flies
had relatively higher response to bacterial filterates compared to protein fed. Higher
numbers of female flies were attracted to bacterial filterates than males across all age
groups. The presence of host decreased the attraction of mature female flies towards the
bacterial sources. The studies on the function of these gut microbes may help to define
relationships between the members of gut community and insect which can lead to the
development of improved management strategies.
 
Date 2016-03-08T16:16:01Z
2016-03-08T16:16:01Z
2013
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/64953
 
Language en_US
 
Format application/pdf
 
Publisher IARI, Division of Entomology, New Delhi