Cucumber Mosaic Virus-Induced Systemic Necrosis in Arabidopsis thaliana: Determinants and Role in Plant Defense

Abstract

Effector-triggered immunity (ETI) is one of the most studied mechanisms of plant resistance to viruses. During ETI, viral proteins are recognized by specific plant R proteins, which most often trigger a hypersensitive response (HR) involving programmed cell death (PCD) and a restriction of infection in the initially infected sites. However, in some plant–virus interactions, ETI leads to a response in which PCD and virus multiplication are not restricted to the entry sites and spread throughout the plant, leading to systemic necrosis. The host and virus genetic determinants, and the consequences of this response in plant–virus coevolution, are still poorly understood. Here, we identified an allelic version of RCY1—an R protein—as the host genetic determinant of broad-spectrum systemic necrosis induced by cucumber mosaic virus (CMV) infection in the Arabidopsis thaliana Co-1 ecotype. Systemic necrosis reduced virus fitness by shortening the infectious period and limiting virus multiplication; thus, this phenotype could be adaptive for the plant population as a defense against CMV. However, the low frequency (less than 1%) of this phenotype in A. thaliana wild populations argues against this hypothesis. These results expand current knowledge on the resistance mechanisms to virus infections associated with ETI in plants.

Metabolic enzymes moonlight as selective autophagy receptors to protect plants against viral-induced cellular damage

“…Should RNAi or hypersensitive response fail to contain the infection, the virus can outpace the immune system, establish VRCs in neighboring cells, and trigger cell death beyond the initial entry point. This could lead to a catastrophic amplification of immune signaling in distal tissues and lead to systemic necrosis 69 , as seen with an engineered plant immune receptor recognizing TuMV 70 and akin to what we observe in autophagy mutants. By controlling the level of EDS1, selective autophagy prevents cell death when the cost outweighs the benefits and promotes organismal survival.…”

Correction: Pagán, I.; García-Arenal, F. Cucumber Mosaic Virus-Induced Systemic Necrosis in Arabidopsis thaliana: Determinants and Role in Plant Defense. Viruses 2022, 14, 2790

“…In the original publication [ 1 ], there was a mistake in Figure 4 as published. Panels A and B are identical and show the time course of CMV multiplication in Co-1 systemically infected rosette leaves.…”

The Hypersensitive Response to Plant Viruses

“…The decrease in resistance efficiency was estimated under HR-inducing and SHR-inducing conditions compared to a compatible reaction in the RCY1-CMV pathosystem, and SHR was suggested to represent a resistance mechanism at the plant population level rather than at the individual level [ 147 , 148 ]. This view of a continuum of resistance has been followed or confirmed in several virus–plant interactions [ 146 , 149 , 150 , 151 , 152 , 153 , 154 ] and has allowed the study of ER, HR and SHR as belonging to a common process with common genes and pathways [ 66 , 155 , 156 ].…”