Plant death caused by inefficient induction of antiviral R-gene-mediated resistance may function as a suicidal population resistance mechanism

Abstract

Land plant genomes carry tens to hundreds of Resistance (R) genes to combat pathogens. The induction of antiviral R-gene-mediated resistance often results in a hypersensitive response (HR), which is characterized by virus containment in the initially infected tissues and programmed cell death (PCD) of the infected cells. Alternatively, systemic HR (SHR) is sometimes observed in certain R gene–virus combinations, such that the virus systemically infects the plant and PCD induction follows the spread of infection, resulting in systemic plant death. SHR has been suggested to be the result of inefficient resistance induction; however, no quantitative comparison has been performed to support this hypothesis. In this study, we report that the average number of viral genomes that establish cell infection decreased by 28.7% and 12.7% upon HR induction by wild-type cucumber mosaic virus and SHR induction by a single-amino acid variant, respectively. These results suggest that a small decrease in the level of resistance induction can change an HR to an SHR. Although SHR appears to be a failure of resistance at the individual level, our simulations imply that suicidal individual death in SHR may function as an antiviral mechanism at the population level, by protecting neighboring uninfected kin plants.

Gain-of-function mutant of movement protein allows systemic transport of a defective tobacco mosaic virus

“…Hypersensitive reaction (HR) is a typical response upon recognition by the host resistance (R) proteins of their corresponding viral factor, e.g., HR in response to the N protein against the helicase domain of the TMV replicase protein ( Tran et al., 2014 ). When the R proteins are absent or insufficiently induced, systemic necrosis appears at later stages of infection ( Abebe et al., 2021 ; Roshan et al., 2018 ). N .…”

A small DNA virus initiates replication with no more than three genome copies per cell

“…The box plots were generated with the JMP Pro 16.0.0 software package. Bottleneck size estimations were performed using a maximum likelihood algorithm described in our previous studies (8, 9, 41), based on the R software package ver. 4.1.3 (42).…”

“…The sequences of LM4, LM4-G and LM4-R encompassing the entire TYLCV DNA (and its modified forms) were verified with Sanger sequencing. Other constructs (p19, 35-GFP, 35S-mCherry) were described previously (27, 40, 41).…”

Perspectives on plant virus diseases in a climate change scenario of elevated temperatures

“…Local HR was still triggered but was unable to restrict virus movement to inoculated leaves, which led to either systemic HR (SHR) or the typical TSWV systemic symptoms at 32 °C (Chung et al 2018;de Ronde et al 2019;Moury et al 1998). While the mechanisms that underpin SHR caused by temperature-sensitivity remain largely unknown, a recent study provides some evidence that inefficient induction of resistance contributes to a switch from HR to SHR (Abebe et al 2021) (Fig. 2, right panel (c)).…”