Identification and function of FAR protein family genes from a transcriptome analysis of Aphelenchoides besseyi.

Motivation: The rice white tip nematode (RWTN) Aphelenchoides besseyi is a migratory plant parasitic nematode that infects the aboveground parts of plants. Fatty acid- and retinoid-binding (FAR) proteins are nematode-specific proteins that are involved in many important biological processes. Genes encoding FAR proteins have been identified in many species of nematodes, which indicated that nematodes may produce more than one type of FAR protein. The main goal of this study is to find new molecular targets including new far genes that will help control RWTN, and reduce the economic damage caused by RWTN. Results: Two RWTN populations with different levels of pathogenicity and reproduction were sequenced and analyzed with next-generation sequencing. 17 087 transcripts were annotated using six databases and 1696 differentially expressed genes (DEGs) were identified between the two RWTN populations. Seven new Ab-far genes were identified from the transcriptome data of the two RWTN populations which is the first to identify multiple far genes in plant parasitic nematodes. This study is the first to identify far genes in the nervous system of nematodes and the first to report a transcriptome sequencing analysis of different RWTN populations. The results help elucidate the genes related to parasitism and pathogenicity and also contribute to the identification of new target genes and development of new methods to control RWTN.