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The β‐ N ‐acetylhexosaminidase gene family in the brown planthopper, Nilaparvata lugens
Author(s) -
Xi Y.,
Pan P.L.,
Zhang C.X.
Publication year - 2015
Publication title -
insect molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.955
H-Index - 93
eISSN - 1365-2583
pISSN - 0962-1075
DOI - 10.1111/imb.12187
Subject(s) - biology , brown planthopper , chitinase , chitin , moulting , gene , transcriptome , rna interference , cuticle (hair) , chitin synthase , nymph , planthopper , rna silencing , rna , genetics , gene expression , botany , biochemistry , hemiptera , chitosan , larva
Abstract β‐ N ‐Acetylhexosaminidases (HEXs) are enzymes that can degrade the chitin oligosaccharides that are produced by the activity of chitinases on chitin in insects. Using bioinformatic methods based on genome and transcriptome databases, 11 β‐ N ‐acetylhexosaminidase genes ( NlHex s) in Nilaparvata lugens were identified and characterized. Phylogenetic analysis revealed a six‐grouped tree topology. The O‐Linked N ‐acetylglucosaminidase (O‐GlcNAcase) group includes NlHex11 , which harbours a catalytic domain that differs from that of the other 10 NlHex s. Observations of the expression of NlHex s during different developmental stages revealed that NlHex4 is expressed with periodicity during moulting. Although the tissue‐specific expression patterns of most NlHex s were nonspecific, NlHex4 was found to be expressed mainly in the female reproductive system as well as in the integument. RNA interference (RNAi) demonstrated failure to shed the old cuticle only in the nymphs treated with double‐stranded RNA (dsRNA) targeting NlHex4 , and these nymphs eventually died; no observable morphological abnormalities were found in insects treated with dsRNAs targeting the other 10 NlHex s. Based on this study and our previous analyses, a ‘5 + 1 + 3’ pattern of chitinolytic enzymes is proposed, in which five chitinases, one NlHEX and three chitin deacetylases are required for moulting in N. lugens . A better understanding of chitin metabolism in the hemimetabolous insect, N. lugens , would be achieved by considering three chitinolytic enzyme families: chitinase, chitin deacetylase and β‐ N ‐acetylhexosaminidase.