Genome-wide identification and analysis of sulfatase and sulfatase modifying factor genes in Bemisia tabaci (Hemiptera: Aleyrodidae)

The invasive pest whitefly (Bemisia tabaci) is a complex species, of which Middle East-Minor Asia 1 (MEAM1) and Mediterranean (MED) are the two most damaging members. Previous research showed that cabbage is frequently infested with MEAM1 but seldomly with MED, and this difference in performance is associated with glucosinolate (GS) content. Some insects can modify GS using glucosinolate sulfatase (SULF), the activity of which is regulated by sulfatase modifying factor 1 (SUMF1); therefore, to increase our understanding of different performances of MEAM1 and MED on cabbage plants, we identified and compared nine putative SULFs and one SUMF in MEAM1 and MED. We found that the lengths of two genes, BtSulf2 and BtSulf4, differed between MEAM1 and MED. The messenger RNA levels of BtSulf4 increased more than 20-fold after MEAM1 and MED adults were exposed to GS, but BtSulf2 expression was only induced by GS in MEAM1. Knockdown of BtSulf2 and BtSulf4 in MEAM1 resulted in a substantial increase in the mortality of GS-treated adults but not in MED. These results indicate that differences in BtSulf2 and BtSulf4 sequences and/or expression may explain why MEAM1 performs better than MED on cabbage. Our results provide a basis for future functional research on SULF and SUMF in B. tabaci.