Helper component-proteinase enhances the activity of 1-deoxy-D-xylulose-5-phosphate synthase and promotes the biosynthesis of plastidic isoprenoids in Potato virus Y-infected tobacco.
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-Pro accumulating in the chloroplasts. During virus infection, the enhancement of plastidic isoprenoid biosynthesis was attributed to the enhancement of DXS activity by HC-Pro. 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.
State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
Heng
H
Li
State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
Dongyuan
D
Ma
State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
Yongsheng
Y
Jin
State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
Yayi
Y
Tu
State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
Liping
L
Liu
State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
Chunxu
C
Leng
State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
Jiangli
J
Dong
State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
Tao
T
Wang
D000040:Abscisic Acid / Q000378:metabolism; D001483:Base Sequence; D060365:Chloroplast Proteins / Q000235:genetics / Q000378:metabolism; D002736:Chloroplasts / Q000201:enzymology; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D015723:Gene Library; D008969:Molecular Sequence Data; D010788:Photosynthesis; D010935:Plant Diseases / Q000821:virology*; D010937:Plant Growth Regulators / Q000378:metabolism; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000821:virology; D030821:Plants, Genetically Modified; D018087:Plastids / Q000378:metabolism; D017800:Potyvirus / Q000502:physiology*; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D013729:Terpenes / Q000378:metabolism*; D014026:Nicotiana / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism / Q000821:virology; D014166:Transferases / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D014764:Viral Proteins / Q000378:metabolism*
D060365:Chloroplast Proteins; D010937:Plant Growth Regulators; D013729:Terpenes; D014764:Viral Proteins; D000040:Abscisic Acid; D014166:Transferases; C109461:deoxyxylulose-5-phosphate synthase; D003546:Cysteine Endopeptidases; C072775:HC-Pro protein, potyvirus
ABA; DXS; MEP pathway; photosynthesis