Bacterial community associated to the pine wilt disease insect vectors Monochamus galloprovincialis and Monochamus alternatus

Abstract

Monochamus beetles are the dispersing vectors of the nematode Bursaphelenchus xylophilus, the causative agent of pine wilt disease (PWD). PWD inflicts significant damages in Eurasian pine forests. Symbiotic microorganisms have a large influence in insect survival. The aim of this study was to characterize the bacterial community associated to PWD vectors in Europe and East Asia using a culture-independent approach. Twenty-three Monochamus galloprovincialis were collected in Portugal (two different locations); twelve Monochamus alternatus were collected in Japan. DNA was extracted from the insects’ tracheas for 16S rDNA analysis through denaturing gradient gel electrophoresis and barcoded pyrosequencing. Enterobacteriales, Pseudomonadales, Vibrionales and Oceanospirilales were present in all samples. Enterobacteriaceae was represented by 52.2% of the total number of reads. Twenty-three OTUs were present in all locations. Significant differences existed between the microbiomes of the two insect species while for M. galloprovincialis there were no significant differences between samples from different Portuguese locations. This study presents a detailed description of the bacterial community colonizing the Monochamus insects’ tracheas. Several of the identified bacterial groups were described previously in association with pine trees and B. xylophilus, and their previously described functions suggest that they may play a relevant role in PWD.

Bacterial Communities Associated With the Pine Wilt Disease Vector Monochamus alternatus (Coleoptera: Cerambycidae) During Different Larval Instars

“…Larval development occurs entirely within the host, requires at least several months, and can kill trees ( Allison et al 2004 ). Bacterial communities associated with subcortically feeding beetles are known to play important roles in facilitating larvae in surviving and developing within their host plants ( Douglas 2009 ; Scully et al 2013 , 2014 ; Alves et al 2016 ). Bacterial communities are reported to contribute to their host beetles’ reproductive success, community interactions and niche diversification ( Cardoza et al 2006 , Scott et al 2008 , Douglas 2009 , Morales-Jiménez et al 2013 ).…”

Differential immune responses of Monochamus alternatus against symbiotic and entomopathogenic fungi

“…Monochamus alternatus (Cerambycidae: Coleoptera) is a species of sapro-xylophagous sawyer beetles (Vicente et al, 2012) that cause significant losses to pine trees (Alves et al, 2016). Moreover, it serves as a main vector of Bur†Contributed equally to this work *Corresponding authors (Lilin Zhao, email: zhaoll@ioz.ac.cn; Jianghua Sun, email: sunjh@ioz.ac.cn) saphelenchus xylophilus, a causal organism of pine wilt disease (PWD), for its tree-to-tree dispersal (Mamiya and Enda, 1972).…”

Bacterial communities of herbivores and pollinators that have co-evolved Cucurbita spp

“…Most of the rare OTUs are from Proteobacteria (44%; 514 out of 1163), followed by OTUs from Firmicutes (26%; 304 out of 1163), Actinobacteria (18.5%; 215 out of 1163), Chloroflexi (3.4%; 39 out of 1163) and Bacteroidetes (2.9%; 34 out of 1163). Other rare, low abundance OTUs are assigned to Acidobacteria, Verrucomicrobia, Plantomycetes, Mollicutes and several Archeal phyla (Funaro et al 2011, Abdul Rahman et al 2015, Alves et al 2016). There was moderate statistical support for differences in the α-diversity (number and evenness) of OTUs in beetles collected in the different geographic locations (Kruskal-Wallis χ 2 =11.9, df = 6, P = 0.06), but there is no clear geographic factor underlying these differences (Figure 2).…”