Antibiotic susceptibility of endosymbionts of papaya mealybug Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae)

Abstract

Aim: The present study aimed to select a powerful tool to evaluate the antibiotic susceptibility of endosymbionts of papaya mealybug. Methodology: Antibiotic Ofloxacin (0.25µg) was used to disrupt the endosymbionts of mealybug. The antibiotic susceptibility of endosymbionts was studied by conventional method; isolation of symbionts in Luria Bertani Agar and Nutrient Agar and also metagenomic analysis was conducted using nanopore sequencing of 16S rRNA gene. Results: Molecular identification of isolates showed Gram-positive bacteria i.e., Bacillus cluasii, B. altitudinis, B. siamensis and Gram-negative bacteria, i.e., Serratia marcescens and Stenotrophomonas maltophilia. Metagenomic analysis using 16S amplicon sequencing resulted in identification of Candidatus Tremblaya Princeps (55%) was more abundant followed by Candidatus Mikella endobia (23%) in untreated mealybug population. Their population was reduced to 7% in Candidatus Tremblaya Princeps and below 1% in Candidatus Mikella endobia. Interpretation: The current study confirms that the metagenomic analysis acts as a power lens to evaluate the antibiotic elimination of endosymbionts, hence with this method future works on developing aposymbiotic mealybugs can be done.

Molecular identification of endosymbiotic bacteria associated with Ferrisia virgata (Homoptera: Coccoidea: Pseudococcidae) infesting cassava (Manihot esculenta)

“…The beneficial role of Firmicutes in degradation of cellulose and hemicellulose in insects has been reported by Brown et al (2012). Likewise antibiotic susceptibility of bacterial endosymbionts viz Bacillus cluasii, B. altitudinis, B. siamensis, Gram-negative bacteria, Serratia marcescens and Stenotrophomonas maltophilia of papaya mealybug Paracoccus marginatus has been documented by Megaladevi and Kennedy (2021). Whereas B. pumilus was found associated with the gut of mealybug, which produce high amount of physiologically active gibberellins and cellulose enzyme (Manero et al, 2001;Ariffin et al, 2006).…”