Genome sequencing of the sweet potato whitefly Bemisia tabaci MED/Q

Authors: XIE, WEN - Chinese Academy Of Agricultural Sciences; CHEN, CHUNHAI - Beijing Genome Institute; YANG, ZEZHONG - Chinese Academy Of Agricultural Sciences; GUO, LITAO - Chinese Academy Of Agricultural Sciences; WANG, DAN - Beijing Genome Institute; CHEN, MING - Beijing Genome Institute; HUANG, JINQUN - Beijing Genome Institute; WEN, YANA - Chinese Academy Of Agricultural Sciences; ZENG, YANG - Chinese Academy Of Agricultural Sciences; LIU, YATING - Chinese Academy Of Agricultural Sciences; Coates, Brad; ZHANG, YOUJUN - Chinese Academy Of Agricultural Sciences

Submitted to: Gigascience
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/10/2017
Publication Date: 3/15/2017
Citation: Xie, W., Chen, C., Yang, Z., Guo, L., Wang, D., Chen, M., Huang, J., Wen, Y., Zeng, Y., Liu, Y., Yang, X., Xia, J., Tian, L., Cui, H., Wu, Q., Wang, S., Xu, B., Li, X., Tan, X., Ghanim, M., Qui, B., Pan, H., Chu, D., Delatte, H., Maruthi, M.N., Ge, F., Zhou, X., Wang, X., Wan, F., Du, Y., Luo, C., Yan, F., Preisser, E.L., Jiao, Z., Coates, B.S., Zhao, J., Gao, Q., Xia, J., Yin, Y., Liu, Y., Brown, J.K., Zhou, X., Zhang, Y. 2017. Genome sequencing of the sweet potato whitefly Bemisia tabaci MED/Q. Gigascience. 5(6):1-7. doi: 10.1093/gigascience/gix018.

Interpretive Summary: Invasive insect species are problematic for agricultural production in the United States and worldwide due to the exposure of local production to new pest pressures that oftentimes lack adequate measures for their control. The resulting high levels of crop damage is significant when invasive species are highly adaptable to new environments, out-compete members in local insect communities, or are resistant to insecticides commonly used by local producers. The whole genome sequence of a globally-invasive whitefly species with well described insecticide resistance traits was sequence by an ARS scientist in collaboration with university and international collaborators. Among the genes predicted in the genome, a class, the cytochome P450s, are known to be involved in the detoxification of insecticides and were shown to be highly duplicated in the whitefly. Additionally, genes involved in amino acid and vitamin biosynthesis were partitioned between the whitefly genome and those of two endosymbiotic bacteria, and the gain of certain genes in the whitefly genome was predicted to occur by acquisition from these bacterial genomes. This whitefly genome resource will be valuable to ARS scientists, as well as university, corporate, and international stakeholders who are engaged in research to understand the adaptive processes of invasive insect species, insect symbiosis with microorganisms, and the evolution of insecticide resistance. This information will be used to devise more effective and sustainable methods to controlling invasive insect species.

Technical Abstract: Crypic and invasive species of whitefly, Bemisia tabaci, are highly destructive agricultural and ornamental crop pest that as a group cause direct feeding damage to host plants and vector a large number of harmful plant viruses. Introductions of B. tabaci are difficult to quarantine and eradicate due to high reproductive rates, broad host plant range, and resistance to chemical insecticides. A 658 Mb draft genome for the B. tabaci Mediterranean (MED) or biotype Q was assembled and annotated with 20,786 protein-coding genes. Metabolic pathways show an expansion in the number of gene family members, in particular, the cytochrome P450 monooxygenases. Additionally, amino acid biosynthesis pathways are partitioning among host and endosymbiont genomes in a manner that is distinct from other hemipteran systems, wherein evidence of horizontal gene transfer to the host genome likely form the basis of obligatory relationships. Putative loss of function of the immune deficiency (IMD) signaling pathway due to gene loss is a shared ancestral trait of hemipteran insects that show competency for hosting endosymbiotic bacteria. This expansion of P450 gene family member may influence the well-noted capacity of MED/Q to adapt to repeated exposures to chemical insecticides, and furthermore, be related to invasiveness in monoculture cropping systems where such applications are prevalent. This whitefly genome establishes a solid foundation for research into the evolution of endosymbiotic relationships, as well as mechanism(s) that may provide a competitive advantages to invasive species, both which likely contribute to the unprecedented worldwide success of B.tabaci invasions.