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.

Abstract

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.

• Authors: Heng Li, Dongyuan Ma, Yongsheng Jin, Yayi Tu, Liping Liu, Chunxu Leng, Jiangli Dong, Tao Wang
• Journal: Plant, cell & environment (Plant Cell Environ) Vol. 38 Issue 10 Pg. 2023-34 (Oct 2015) ISSN: 1365-3040 [Electronic] United States
• PMID: 25736930 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2015 John Wiley & Sons Ltd.

Chemical References

• Chloroplast Proteins
• Plant Growth Regulators
• Terpenes
• Viral Proteins
• Abscisic Acid
• Transferases
• deoxyxylulose-5-phosphate synthase
• Cysteine Endopeptidases
• HC-Pro protein, potyvirus

Topics

• Abscisic Acid (metabolism)
• Base Sequence
• Chloroplast Proteins (genetics, metabolism)
• Chloroplasts (enzymology)
• Cysteine Endopeptidases (metabolism)
• Gene Library
• Molecular Sequence Data
• Photosynthesis
• Plant Diseases (virology)
• Plant Growth Regulators (metabolism)
• Plant Leaves (enzymology, genetics, metabolism, virology)
• Plants, Genetically Modified
• Plastids (metabolism)
• Potyvirus (physiology)
• Sequence Analysis, DNA
• Sequence Deletion
• Terpenes (metabolism)
• Tobacco (enzymology, genetics, metabolism, virology)
• Transferases (genetics, metabolism)
• Two-Hybrid System Techniques
• Viral Proteins (metabolism)