Ngày nhận bài: 15-03-2017 / Ngày duyệt đăng: 17-07-2017 / Ngày xuất bản: 06-08-2025
Porphyrins play vital roles in various biological processes. This study focused on porphyrin biosynthesis control under drought stress in rice plant. The results showed that in response to drought treatment by water withholding, the level of porphyrin intermediates greatly decreased after 36 h of treatment whereas final products (chlorophyll and heme) content just slightly reduced after 60 h of drought stress. The activity of some key enzymes in porphyrin pathway, including ALA-synthesizing capacity, PPO activity, Mg-chelatase activity, Fe-chelatase activity reduced together with the down-regulation of porphyrin biosynthetic genes and nuclear-encoded photosynthetic genes, especially at 48 and 60 h after treatment. It indicated a sensitivity of porphyrin pathway to drought stress. And it also demonstrated a tight control of porphyrin biosynthesis in order to prevent the accumulation of toxic metabolic intermediates by down-regulation of their biosynthesis under drought condition.
Abbreviates: ALA: 5-aminolevulinic acid, ALAD: ALA dehydratase, CHLD: D-subunit of Mg-chelatase, CHLH: H-subunit of Mg-chelatase, CHLI: I-subunit of Mg-chelatase, FC: ferrochelatase, GSA: glutamate 1-semialdehyde aminotransferase, HEMA: glutamyl-tRNA reductase, MgProto: Mg-protoporphyrin IX; MgProto ME: Mg-protoporphyrin IX monomethylester; Pchlide: protochlorophyllide, PORB: protochlorophyllide oxidoreductase B, PPO: protoporphyrinogen oxidase, Proto IX: protoporphyrin IX, ROS: reactive oxygen species.
