Isolation and characterization of a Serratia marcescens with insecticidal activity from Polyphylla olivieri (Col.: Scarabaeidae)

Abstract

Members of the genus Serratia are known for their abilities to infect insects. In this study, a red-pigmented S. marcescens was isolated and characterized from the infected larvae of Polyphylla olivieri using bacterial cultivation, phylogenetic analysis as well as bioassays against larvae of the two insect pests, Plodia interpunctella and Ephestia kuehniella. Comparative 16S rRNA and groEL gene sequence BLAST analyses strongly suggested that the isolated strain should be placed in the genus Serratia, sharing high sequence similarities with several strain of S. marcescens associated with insects.Phylogenetic analysis placed the isolated bacterium with other S. marcescens bacteria in a clade with high bootstrapping values. To assess pathogenicity of the S. marcescens isolate, the bacterial cells were either injected into the haemolymph of the fifth-instar larvae or added to the diets of insects. Survival curves of the control insects and those challenged with six different concentrations of S. marcescens showed that the S. marcescens isolate significantly reduced survival rates of the larvae. The LC 50 s of the bacterium on P. interpunctella and E. kuehniella were 1992.26 and 1.09 × 10 4 (CFU/μl) for injection bioassays at 6 h post-injection, and 4.48 × 10 4 and 1.96 × 10 5 (CFU/10 μl)for feeding bioassays at 24 h post-feeding, respectively. Injection of the bacterial culture supernatant into the larvae led to continuous bleeding from the site of injection, while injection of heat-treated culture supernatant of the bacterium did not cause continuous bleeding. Together, our results showed the possibility of using this S. marcescens isolate in microbial control of the insect pests after addressing the safety concerns. Moreover, it might be considered as a source of useful bioactive molecules and genes with application in insect control and biotechnology via developing insectresistant plants.

Enhanced Tolerance against a Fungal Pathogen and Insect Resistance in Transgenic Tobacco Plants Overexpressing an Endochitinase Gene from Serratia marcescens

“…Chitinolytic bacteria have been correlated with insect biocontrol [23] and considered as a source of useful bioactive molecules and genes for this application [24]. Insect chitinases play a critical role in insect growth and development, and their overexpression at appropriate times could disrupt the cuticle and/or gut physiology in many insect species leading to negative effects and even death [25].…”

“…Insect chitinases play a critical role in insect growth and development, and their overexpression at appropriate times could disrupt the cuticle and/or gut physiology in many insect species leading to negative effects and even death [25]. In fact, the usage of Gram negative bacterial strains like S. marcescens has been observed to be a great biocontrol agent against Spodoptera litura at different developmental stages [24,26], due to its ability to produce different chitinolytic enzymes [27]. In this way, the search for chitinolytic enzymes produced in transgenic plants with insecticidal activity is of scientific interest.…”

Cannibalism as a Possible Entry Route for Opportunistic Pathogenic Bacteria to Insect Hosts, Exemplified by Pseudomonas aeruginosa, a Pathogen of the Giant Mealworm Zophobas morio

“…Serratia marcescens is present as part of the gut microbiota of some sandflies and triatomine species [ 11 ]. Examples of S. marcescens , isolated as a pathogen from insects of the orders Coleoptera, Diptera, Orthoptera, and Lepidoptera, have been reported [ 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Similarly, P. aeruginosa has been isolated from different weevil species (the pecan weevil Curculio caryae [ 14 ]; the southern pine weevil Dendroctonus brevicomis [ 12 ]; the red palm weevil Rynchophorus ferrugineus [ 19 ], the tobacco and tomato hornworms Manduca sexta and M. quinquemaculata [ 20 ], from Schistocerca gregaria eggs [ 21 ] in the wild and from several other insect species.…”

Efficacy Test on Some Entomopathogenic Bacterial Isolates of the Periplaneta americana and Blatella germanica Cockroaches (Orthoptera) at Laboratory Scale

“…According to Krishanti et al (2017), BLSP4 and BLSP3 were identified as Serratia marcescens (similarity 94%) and Staphylococcus sciuri (similarity 99%) respectively through molecular identification of the gene encoding 16S rDNA. Serratia (Monica et al, 2015), Plodia interpunctella and Ephestia kuehniella fifth instar larvae (Bidari et al, 2017), and also Spodoptera litura (Aggarwal et al, 2015). Meanwhile, the Staphylococcus sciuri species group consists of five species that are most often regarded as commensal animal-associated bacteria.…”