Downregulation of Light-Harvesting Complex II Induces ROS-Mediated Defense Against Turnip Mosaic Virus Infection in Nicotiana benthamiana

Abstract

The light-harvesting chlorophyll a/b complex protein 3 (LHCB3) of photosystem II plays important roles distributing the excitation energy and modulating the rate of state transition and stomatal response to abscisic acid. However, the functions of LHCB3 in plant immunity have not been well investigated. Here, we show that the expression of LHCB3 in Nicotiana benthamiana (NbLHCB3) was down-regulated by turnip mosaic virus (TuMV) infection. When NbLHCB3 was silenced by tobacco rattle virus-induced gene silencing, systemic infection of TuMV was inhibited. H2O2 was over-accumulated in NbLHCB3-silenced plants. Chemical treatment to inhibit or eliminate reactive oxygen species (ROS) impaired the resistance of the NbLHCB3-silenced plants to TuMV infection. Co-silencing of NbLHCB3 with genes involved in ROS production compromised the resistance of plants to TuMV but co-silencing of NbLHCB3 with genes in the ROS scavenging pathway increased resistance to the virus. Transgenic plants overexpressing NbLHCB3 were more susceptible to TuMV. These results indicate that downregulation of NbLHCB3 is involved in defense against TuMV by inducing ROS production.

Plant virology in the 21st century in China: Recent advances and future directions

“…Additionally, plant chloroplasts play a role in ROS accumulation, influencing viral infection. The downregulation of light-harvesting complex II promotes plant antiviral defenses against TuMV infection by inducing ROS production in N. benthamiana (Qiu et al, 2021). Furthermore, some host factors are known to mitigate TMV-induced oxidative damage by balancing ROS production and scavenging processes.…”

Transcriptomic and genetic approaches reveal that low-light-induced disease susceptibility is related to cellular oxidative stress in tomato

“…Research findings indicate that LHCB5, a light-harvesting complex II protein of rice, is phosphorylated under high light conditions, thereby boosting plant defense against blast fungus Magnaporthe oryzae through activating the ROS burst in the chloroplasts [ 20 ]. Similarly, LHCB3 is also crucial for plant immunity, as NbLHCB3 enhances ROS generation to defend against turnip mosaic virus (TuMV) [ 21 ]. The expression of ascorbate peroxidase 2 ( APX2 ) gene can be rapidly induced by high light stress, stimulating ROS generation in response to light changes in Arabidopsis [ 22 ].…”

“…In contrast to the well-established connection between high-light-induced ROS signaling and plant defense [ 20 , 21 , 24 ], the involvement of ROS in the defense responses under low light conditions has gained less attention. As high light induces an ROS burst as a signal, it is reasonable to hypothesize that the decrease in ROS may be responsible for the increased disease susceptibility of plants under low light.…”

Red and Blue Light Induce Soybean Resistance to Soybean Mosaic Virus Infection through the Coordination of Salicylic Acid and Jasmonic Acid Defense Pathways

“…Light intensity modulates the efficiency of virus seed transmission through modifications in plant tolerance [14]. The down-regulation of Light-Harvesting Complex II induces reactive oxygen species (ROS)-mediated defense against Turnip mosaic virus infection in Nicotiana benthamiana [15]. Cryptochrome 2 and phototropin 2 regulate resistance protein-mediated viral defense by negatively regulating E3 ubiquitin ligase [16].…”