AUTHOR=Bi Ji’an , Yang Yong , Chen Binghua , Zhao Jinping , Chen Zhuo , Song Baoan , Chen Jianping , Yan Fei 

TITLE=Retardation of the Calvin Cycle Contributes to the Reduced CO2 Assimilation Ability of Rice Stripe Virus-Infected N. benthamiana and Suppresses Viral Infection

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.00568

DOI=10.3389/fmicb.2019.00568

ISSN=1664-302X

ABSTRACT=<p>Rice stripe virus (RSV) is naturally transmitted by the small brown planthopper and infects plants of the family <italic>Poaceae</italic>. Under laboratory conditions, RSV can infect <italic>Nicotiana benthamiana</italic> by mechanical inoculation, providing a useful system to study RSV–plant interactions. Measurements of CO<sub>2</sub> assimilation ability and PSII photochemical efficiency showed that these were both reduced in <italic>N. benthamiana</italic> plants infected by RSV. These plants also had decreased expression of the <italic>N. benthamiana Phosphoribulokinases</italic> (<italic>NbPRKs</italic>), the key gene in the Calvin cycle. When the <italic>NbPRKs</italic> were silenced using the TRV-Virus Induced Gene Silencing system, the plants had decreased CO<sub>2</sub> assimilation ability, indicating that the downregulated expression of <italic>NbPRKs</italic> contributes to the reduced CO<sub>2</sub> assimilation ability of RSV-infected plants. Additionally, <italic>NbPRKs</italic>-silenced plants were more resistant to RSV. Similarly, resistance was enhanced by silencing of either <italic>N. benthamiana Rubisco</italic> small subunit (<italic>NbRbCS</italic>) or <italic>Phosphoglycerate kinase</italic> (<italic>NbPGK</italic>), two other key genes in the Calvin cycle. Conversely, transgenic plants overexpressing <italic>NbPRK1</italic> were more susceptible to RSV infection. The results suggest that a normally functional Calvin cycle may be necessary for RSV infection of <italic>N. benthamiana</italic>.</p>