Complete genome sequencing of nematode Aphelenchoides besseyi, an economically important pest causing rice white-tip disease

Aphelenchoides besseyi is a seed-borne plant-parasitic nematode that causes severe rice yield losses worldwide. In the present study, the A. besseyi Anhui-1 strain isolated from rice in China was sequenced with a hybrid method combining PacBio long reads and Illumina short reads, and subsequently annotated using available transcriptome references. The genome assembly consists of 166 scaffolds totaling 50.3 Mb, with an N50 of 1.262 Mb and a maximum scaffold length of 9.17 Mb. A total of 16,343 genes were annotated in the genome, with 94 gene families expanded while 70 families contracted specifically in A. besseyi. Furthermore, gene function analysis demonstrated that the genes related to drought tolerance were enriched, and cellulase genes were horizontally acquired from eukaryotic origin. Our findings provide resources to interpret the biology, evolution, ecology, and functional diversities of Aphelenchoides spp. in the light of genomics.