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Helper component‐proteinase enhances the activity of 1‐deoxy‐ D ‐xylulose‐5‐phosphate synthase and promotes the biosynthesis of plastidic isoprenoids in P otato virus Y ‐infected tobacco
Author(s) -
Li Heng,
Ma Dongyuan,
Jin Yongsheng,
Tu Yayi,
Liu Liping,
Leng Chunxu,
Dong Jiangli,
Wang Tao
Publication year - 2015
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12526
Subject(s) - potato virus y , bimolecular fluorescence complementation , biochemistry , chloroplast , biology , biosynthesis , terpenoid , atp synthase , enzyme , virus , plant virus , yeast , virology , gene
Virus‐infected plants show strong morphological and physiological alterations. Many physiological processes in chloroplast are affected, including the plastidic isoprenoid biosynthetic pathway [the 2C‐methyl‐D‐erythritol‐4‐phosphate ( MEP ) pathway]; indeed, isoprenoid contents have been demonstrated to be altered in virus‐infected plants. In this study, we found that the levels of photosynthetic pigments and abscisic acid ( ABA ) were altered in Potato virus Y ( PVY )‐infected tobacco. Using yeast two‐hybrid assays, we demonstrated an interaction between virus protein PVY helper component‐proteinase ( HC ‐Pro) and tobacco chloroplast protein 1‐deoxy‐ D ‐xylulose‐5‐phosphate synthase ( NtDXS ). This interaction was confirmed using bimolecular fluorescence complementation ( BiFC ) assays and pull‐down assays. The Transket_pyr domain (residues 394–561) of NtDXS was required for interaction with HC ‐Pro, while the N ‐terminal region of HC ‐Pro (residues 1–97) was necessary for interaction with NtDXS . Using in vitro enzyme activity assays, PVY HC ‐Pro was found to promote the synthase activity of NtDXS . We observed increases in photosynthetic pigment contents and ABA levels in transgenic plants with HC ‐ P ro accumulating in the chloroplasts. During virus infection, the enhancement of plastidic isoprenoid biosynthesis was attributed to the enhancement of DXS activity by HC ‐ P ro. Our study reveals a new role of HC ‐Pro in the host plant metabolic system and will contribute to the study of host–virus relationships.