Resistance Mechanism of Cultured Plant Cells to Tobacco Mosaic Virus

Abstract

In somaclonal tissues obtained from systemically TMV‐infected tobacco plants, a relation between changes of TMV amounts and the callus growth was examined. The culture medium was suitable for maintaining a constant concentration of TMV as well as active callus growth. By using the shake‐culture method, somaclonal tissues were separated into two classes on the basis of callus sizes. In large callus tissues, TMV amounts were constant during subculturing but the tissues did not either grow or release the newly divided cells after the last subculture. On the other hand, smaller callus tissues grew markedly and the TMV amounts were conspicuously lowered. After shake‐subculture of smaller tissues, they were successfully regenerated to plantlets. None of the plantlets expressed any mosaic symptoms, while plantlets from the original somaclones showed severe mosaic symptoms of TMV in leaflets. Thus, the present report describes the successful production of virus‐free plantlets from infected somaclonal callus cultures.

Elimination of pepper mild mottle virus from infected tobacco (Nicotiana benthamiana L.) plants by callus culture and the sieving technique

“…Among 27 tested plantlets (for each replication of the experiment) regenerated from micro-calli/sieve size of 250, 300, and 425 μm in diameter, 25, 9, and 5 were negative on average, respectively, for PMMoV by RT-PCR, which confirmed that three tested sieve sizes produced significantly different (P ≥ 0.00001) percentages of PMMoV virus-free tobacco plants and the 250 μm sieve size provided the highest percentage (91.67±3.31) of PMMoV virus-free tobacco plants followed by sieve size 300 μm (33.92±1.08) and 425 μm (18.52± 1.51) under in vitro conditions. This result is consistent with the findings of Toyoda et al (1985) where TMV virus-free tobacco plantlets were produced only from smaller-sized callus cultures.…”

“…However, as viruses can translocate between cells at a slow pace via plasmodesmata, it is possible that the invasion of viruses through plasmodesmata was limited to the older cells in the callus, while the rapidly proliferating young cells escaped virus invasion. This may also explain the results of previous studies showing the regeneration of virus-free plantlets from callus culture by multiple steps of subculture (Toyoda et al 1985;Duran-Vila et al 1991). In the present study, the regenerated plantlets were transferred to the greenhouse and remained virus-free for up to 8 mo (Fig.…”

Microbial hazards in plant tissue and cell cultures

“…Their latency in vitro is thought to be caused by plant resistance mechanisms, which are more active under in vitro conditions, but very little information is available confirming this hypothesis (Leifert et al, 1994a). Production of antiviral compounds in vitro was demonstrated and certain pathogenesis-related (PR-) proteins involved in resistance to viruses have been shown to increase in response to certain growth regulators used in plant tissue and cell culture (Omura and Wakimoto, 1978;Darvill and Albersheim, 1984;Toyoda et al, 1985;Daub, 1986;Rollo et al, 1986;White et al, 1986;Apostle et al, 1989;Thynn et al, 1989).…”

Effects of modulation of potassium channels in tobacco mosaic virus elimination

“…Callus culture was applied to eliminate viruses in several plant species (Goussard and Wiid 1992;Niimi et al 2001;Gambino et al 2006;Sharma et al 2008) and the heterogeneous distribution of virus (Scagliusi et al 2002) can play a significant role in antiviral effectiveness. Thus, the uneven distribution of the virus in mother calli was proposed to be due to the production of virus-infected and virus-free cell clusters during the callus disruption process (Kwon et al, 2012), explaining the results of previous studies showing the regeneration of virus-free plantlets from callus culture by multiple steps of subculture or production of TMV virus-free tobacco plantlets only from smaller-sized callus cultures (Toyoda et al 1985).…”