Bxy‐fuca encoding α‐L‐fucosidase plays crucial roles in development and reproduction of the pathogenic pinewood nematode, Bursaphelenchus xylophilus

Abstract

BACKGROUND The pine wood nematode (PWN) Bursaphelenchus xylophilus is the causal agent of pine wilt disease (PWD). This disease is a serious threat to pine forests globally. The fuca gene encodes α‐L‐fucosidase, which plays crucial roles in numerous biological and pathological processes in bacteria, fungi, plants and animals. To find promising control strategies against PWD, we investigated the expression and functions of Bxy‐fuca in B. xylophilus. RESULTS Bxy‐fuca encoding α‐L‐fucosidase is highly conserved within the deduced functional domains and key residues. It is expressed continuously across all developmental stages of B. xylophilus. mRNA in situ hybridization demonstrated that Bxy‐fuca was mainly localized in the body wall muscles and intestine. RNA interference indicated that the zygotic expression of Bxy‐fuca was indispensable for embryogenesis. The rate of B. xylophilus egg hatch was significantly decreased after Bxy‐fuca was interfered. Postembryonic silence of Bxy‐fuca resulted in a dramatic decrease in the longevity of and the total number of eggs produced by B. xylophilus. In addition, the motility of the nematode was greatly hampered with a significant drop in head thrashing frequency. CONCLUSION Bxy‐fuca plays crucial roles in development, lifespan and reproduction of B. xylophilus. Our results provide promising hints for control of PWD by blocking embryogenesis and ontogenesis, decreasing nematode fecundity, and disrupting the connection between B. xylophilus and its vector beetle by preventing nematode movement into the tracheal system. © 2019 Society of Chemical Industry

α-l-Fucosidases from Bursaphelenchus xylophilus Secretome—Molecular Characterization and Their Possible Role in Breaking Down Plant Cell Walls

“…For BxFUCA1, a C-terminal domain composed of seven anti-parallel β-sheets and a N-terminal domain formed by five parallel β-sheets arranged around the central axis and surrounded by eight α-helices forming the catalytic pocket, were predicted. The BxFUCA1 3-D structure is similar to the Bxy-FUCA structure predicted by Tang et al [14]. For BxFUCA2, the C-terminal domain was composed of eight anti-parallel β-sheets and the Nterminal catalytic domain was formed by five parallel β-sheets arranged around the central axis and surrounded by eight α-helices (Figure 4).…”

“…Although not mentioned by the authors as predicted CWDE in published B. xylophilus genome [2,3] or even first published secretome [4], three genes and proteins with possible fucosidase activity belonging to GH29 were identified in B. xylophilus genome and secretome and were found listed in the supplementary tables of the respective publications. These proteins were identified as GH29 and from these, only the one coded by the BXY_0325100.1 gene (Bxy-fuca) was further characterized and described as playing a crucial role in the development, lifespan and reproduction of B. xylophilus [14]. The two proteins identified as α-l-fucosidases in our previous study on B. xylophilus secretome [5] were further characterized in this study, and a new α-l-fucosidase of B. xylophilus (BxFUCA2) was described.…”

“…These proteins may also act on other fucosylated substrates like pectin or glycoproteins, contributing to deconstruction of the plant cell wall. The possible involvement of BxFUCA1 in hemicellulose digestion along with its crucial role in the development, lifespan and reproduction of B. xylophilus, has recently been suggested in a work describing the Bxy-fuca gene [14].…”

“…However, the inability of a nematode to degrade any component of the plant cell wall may result in unsuccessful infection, thus, all possible carbohydrate active enzymes that could act on plant cell wall degradation must be further explored. Recently, a α-l-fucosidase gene from B. xylophilus (Bxy-fuca) was characterized and associated with nematode development, lifespan and reproduction [14]. In our previous studies, two α-l-fucosidases were detected in B. xylophilus secretome [5] and in the present study, the molecular characterization of these two α-L-fucosidases was performed, thus providing new insights into the possible role of these proteins in degrading the plant cell walls and in PWN pathogenicity.…”

“…Analyzing B. xylophilus genome [2], three genes (BXY_1120100.1, BXY_0325100.1 and BXY_0325000.1) were identified as coding putative GH29 proteins. After analyzing B. xylophilus transcriptome data from B. xylophilus BioProject PRJNA192936 [15], only two proteins were identified with possible α-l-fucosidase activity belonging to GH29, one of them (All_gs454_001152) was 100% identical to the genome predicted BXY_0325100.1 gene product, named BxFUCA1, which corresponds to the α-l-fucosidase (Bxy-FUCA) recently described and characterized by Tang et al [14]. The other fucosidase (All_gs454_002563) presented 57%, 67% and 52% sequence identity to the genome predicted BXY_1120100.1, BXY_0325100.1 and BXY_0325000.1 gene products, respectively.…”