In vivo infection of Bursaphelenchus xylophilus by the fungus Esteya vermicola

Abstract

BACKGROUNDAs the causal agent of pine wilt disease, Bursaphelenchus xylophilus, is a serious pathogen of forest pine trees. Esteya vermicola is a nematophagous fungus of B. xylophilus and exhibits great potential as a biological control agent. However, the in vivo infection mechanism of E. vermicola on B. xylophilus is unclear. Experiments were conducted to study the colonization of host plant and infection of B. xylophilus by E. vermicola inside pine tree xylem.RESULTSA green fluorescent protein (GFP)‐tagged E. vermicola transformant was constructed as a biomarker to study the in vivo colonization and infection of B. xylophilus in pine trees. The in vitro infection of B. xylophilus by E. vermicola was observed through GFP expression. The bacilloid conidia produced by trophic hyphae in the body of the nematode are described. Additionally, the monitoring of in vivo colonization by GFP‐tagged E. vermicola showed the germination and hyphal extension of this fungus after inoculation. Moreover, B. xylophilus infected by this biocontrol agent were extracted from healthy seedlings and observed in the xylem of trees that were wilting due to pine wilt disease.CONCLUSIONEvidence of fungal colonization and infection of B. xylophilus by E. vermicola is provided to improve our understanding of the in vivo infection mechanisms used by this nematophagous fungus against B. xylophilus. The infection of B. xylophilus by E. vermicola was inferred to begin with the implantation of propagules, and this inference will require future investigation.The colonization of Esteya vermicola in host pine tree xylem and the in vivo infection of pinewood nematode by E. vermicola were investigated using the green fluorescence protein transformant. © 2020 Society of Chemical Industry

The specialization ofEsteya vermicolahyphae in infection toBursaphelenchus xylophilusand its colonization of pine tree

“…Additionally, the amount of E. vermicola in the body of extracted PWNs was quantified using TaqMan PCR quantification ( Table 2). The results showed that E. vermicola xylophilus by E. vermicola has been studied [11,19], the specific implantation method and specialized fungal hyphae in PWN infection were first reported in the present study.…”

“…The infection process of the plant-parasitic nematode by endoparasitic fungi has been investigated using the GFP-labeled fungal transformant [13,20,21] [11]. Subsequently, the conidia of E. vermicola were germinated and grew within a few days after inoculation and extended upward and downward.…”

“…Hyphae of E. vermicola and parasitized PWNs were observed only from wood sections of dead and wilting seedlings inoculated with a conidial suspension of the fungus [9,10]. Recently, the fungal germination and colonization of E. vermicola were live-cell visualized with the help of a green fluorescence protein (GFP)transformed mutant CNU120806gfp [11].…”

Migration of pinewood nematode promotes the colonization of Esteya vermicola in pine tree

“…Under in vitro conditions, PWNs were infected and killed in few days by E. vermicola (Chu et al., 2015). However, the infected PWNs have high activity within 2 days after being infected by E. vermicola (Wang et al., 2008; Wang, Wang, et al., 2020). The migration of fungal infected PWN in the susceptible pine tree resin channel helped E. vermicola dispersion.…”

Identification of the Extracellular Nuclease Influencing Soaking RNA Interference Efficiency in Bursaphelenchus xylophilus

“…The pine wood nematode, Bursaphelenchus xylophilus , is a notorious, invasive, plant-parasitic nematode that causes pine wilt disease [ 1 ], which is the most complex and devastating disease in forest ecosystems in China, South Korea, Japan, Portugal and other European countries [ 2 , 3 , 4 ]. It has caused significant economic and ecological damage in China since it was first reported in Nanjing in 1982 [ 5 ].…”