Developmentally regulated Arabidopsis thaliana susceptibility to tomato spotted wilt virus infection

Abstract

Tomato spotted wilt virus (TSWV) is one of the most devastating plant viruses and often causes severe crop losses worldwide. Generally, mature plants become more resistant to pathogens, known as adult plant resistance. In this study, we demonstrated a new phenomenon involving developmentally regulated susceptibility of Arabidopsis thaliana to TSWV. We found that Arabidopsis plants become more susceptible to TSWV as plants mature. Most young 3-week-old Arabidopsis were not infected by TSWV. Infection of TSWV in 4-, 5-, and 6-week-old Arabidopsis increased from 9%, 21%, and 25%, respectively, to 100% in 7-to 8-week-old Arabidopsis plants. Different isolates of TSWV and different tospoviruses show a low rate of infection in young Arabidopsis but a high rate in mature plants. When Arabidopsis dcl2/3/4 or rdr1/2/6 mutant plants were inoculated with TSWV, similar results as observed for the wild-type Arabidopsis plants were obtained. A cell-to-cell movement assay showed that the intercellular movement efficiency of TSWV NSm:GFP fusion was significantly higher in 8-week-old Arabidopsis leaves compared with 4-week-old Arabidopsis leaves. Moreover, the expression levels of pectin methylesterase and β-1,3glucanase, which play critical roles in macromolecule cell-to-cell trafficking, were significantly up-regulated in 8-week-old Arabidopsis leaves compared with 4-week-old Arabidopsis leaves during TSWV infection. To date, this mature plant susceptibility to pathogen infections has rarely been investigated. Thus, the findings presented here should advance our knowledge on the developmentally regulated mature host susceptibility to plant virus infection. K E Y W O R D S Arabidopsis thaliana, developmentally regulated susceptibility, mature-dependent pathogen infection, Tomato spotted wilt virus

Stepwise artificial evolution of an Sw‐5b immune receptor extends its resistance spectrum against resistance‐breaking isolates of Tomato spotted wilt virus

“…The OD 600 of L (+)opt was adjusted to 1.5, which substantially improved its virus rescue efficiency up to 85‐100%. Inoculation of TZSV and INSV was performed as previously described (Huang et al ., 2020). The inoculated tobacco plants were grown in a growth chamber as described above.…”

The Tobamoviral Movement Protein: A “Conditioner” to Create a Favorable Environment for Intercellular Spread of Infection

“…Experiments studying the growing edge of the infection focus are also interesting because the behavior of MP-GFP was different from the behavior of the recombinant MP produced in E. coli, which appeared in cells distant from the injected cell after microinjection (Waigmann et al, 1994). Experiments in which DNA encoding MP-GFP was delivered into cells using low-pressure microprojectile bombardment without injuring the leaf (Crawford and Zambryski, 2000;Crawford and Zambryski, 2001) or MP-2xGFP-encoding plasmid delivered via agroinfiltration (Burch-Smith and Zambryski, 2010) demonstrated that TMV MP, similar to the cucumber mosaic virus 3a MP (Itaya et al, 1997) or the tomato spotted wilt virus NSm MP (Huang et al, 2020), showed autonomy from other viral factors, i.e., could independently move to neighboring cells in the absence of viral RNA, but remained relatively close to the initial cell with the introduced MP-encoding DNA. MP-GFP trafficked to an average of eight (Crawford and Zambryski, 2000) or nine (Crawford and Zambryski, 2001) cells adjacent to the bombarded cell.…”

Diversity of Plant Virus Movement Proteins: What Do They Have in Common?

“…For some viruses transported as virions, the MPs, in addition to forming tubular structures, can apparently perform other functions. For example, tomato spotted wilt virus (TSWV) NSm MP is able to move independently of other viral components from a "0" cell to neighboring healthy cells of a model plant such as A. thaliana [73]. It is also known that MPs of tubule-forming CPMV are capable of transporting vRNPs in the AMV model system [30], which indicates the likelihood of intercellular transport in tubule-forming viruses using both vRNPs and virions [4].…”