PVA infection and host methionine cycle

Viral proteins reprogram several processes associated with primary metabolism by interacting with the host’s metabolic enzymes.

The methionine cycle (MTC), also known as activated methionine cycle, is among those primary metabolic pathways affected by plant virus infection (reviewed in [1]). We found that PVA protein helper component-proteinase (HCPro) interacts with the enzymes of the host methionine cycle, S-adenosyl-L-methionine synthase and S-adenosyl-L-homocysteine hydrolase, to suppress RNA silencing and promote infection [2] and that HCPro is up-regulating via its interactions with MTC enzymes the high potato virus X titers and great symptom severity during mixed PVA-PVX infection [3].

  1. Mäkinen K. and De. S. 2019. ”The significance of methionine cycle enzymes in plant virus infections” Review. Current Opinion in Plant Biology, 50:67–75.
  2. Ivanov, K.I., Eskelin, K., Bašić, M., De, S., Lõhmus, A., Varjosalo, M., and Mäkinen K. (2016). ”Molecular insights into the function of the viral RNA silencing suppressor HC-pro” The Plant Journal, 85, 30–45. DOI:
  3. De, S., Chavez-Calvillo, G., Wahlsten, M. and Mäkinen, K. 2018. ”Disruption of the methionine cycle and reduced cellular gluthathione levels underlie potex-potyvirus synergism in Nicotiana benthamiana” Molecular Plant Pathology, 19, 1820–1835. doi: