The Role of Serratomolide-like Amino Lipids Produced by Bacteria of Genus Serratia in Nematicidal Activity.

Catarina Marques-Pereira,Diogo Neves Proença,Paula V Morais

doi:10.3390/pathogens11020198

Abstract

Bursaphelenchus xylophilus, also known as pinewood nematode (PWN), is the pathogenic agent of pine wilt disease (PWD), which affects pine trees around the world. Infection spread globally through international wood commerce and locally by vector beetles, threatening the wood world economy. As climate changes, more countries are becoming susceptible to PWD and, to prevent disease spread and limit economic and ecological losses, better knowledge about this pathogenic agent is needed. Serratia strains, present in the endophytic community of pine trees and carried by PWN, may play an important role in PWD. This work aimed to better understand the interaction between Serratia strains and B. xylophilus and to assess the nematicidal potential of serratomolide-like molecules produced by Serratia strains. Serrawettin gene presence was evaluated in selected Serratia strains. Mortality tests were performed with bacteria supernatants, and extracted amino lipids, against Caenorhabditis elegans (model organism) and B. xylophilus to determine their nematicidal potential. Attraction tests were performed with C. elegans. Concentrated supernatants of Serratia strains with serratamolide-like lipopeptides were able to kill more than 77% of B. xylophilus after 72 h. Eight specific amino lipids showed a high nematicidal activity against B. xylophilus. We conclude that, for some Serratia strains, their supernatants and specific amino lipids showed nematicidal activity against B. xylophilus.

Highlights

Pine forests face a global threat, pine wilt disease (PWD), caused by pinewood nematode (PWN) Bursaphelenchus xylophilus which is carried from tree to tree by Monochamus galloprovincialis vector beetles [1]
Concentrated supernatants presented better nematicidal results than non-concentrated supernatants and were able to kill more than 57% of B. xylophilus after 72 h. These results show that nematicidal activity increased as expected when supernatant components were more concentrated, which suggests that some extracellular components in Serratia supernatants possess strong nematicidal activity against nematodes
These results suggest that nematicidal activity is a characteristic that can be found in Serratia strains independently of the sample site

Summary

Introduction

Pine forests face a global threat, pine wilt disease (PWD), caused by pinewood nematode (PWN) Bursaphelenchus xylophilus which is carried from tree to tree by Monochamus galloprovincialis vector beetles [1]. B. xylophilus is native to North America and was first reported in Japan, where it rapidly caused a major pine forestry catastrophe [2]. It was spread to other Asian countries as China, Korea and Taiwan, causing severe economic damages [3]. PWN was later reported in Nigeria and Mexico [4,5]. Portugal was the first European country to detect PWD; PWN was detected in 1999 [6] and its vector. M. galloprovincialis was confirmed in 2001 [7]. The B. xylophilus is listed as a European and Mediterranean Plant Protection Organization (EPPO) A2 quarantine pest in the European

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