Figure 3.

Revised pathway of saxitoxin biosynthesis in A. catenella (Cited and modified from previous reports [10,27]). The sxt genes identified are in circles and those not identified in this study are in dashed circles. sxt genes identified for the first time in dinoflagellates are labeled in solid circles: sxtO was involved in conversion of STX analogs; sxtZ participated in regulation of STX biosynthesis. STX biosynthesis steps in a red dashed box represent terminated reactions due to depressed expression of sxtA long transcripts in ACHK-NT, which resulted in the ability loss of toxin production.