Thermal inactivation of cherry leaf roll virus in tissue cultures of Nicotiana rustica raised from seeds and meristem‐tips

Abstract

SUMMARY Nicotiana rustica tissue cultures derived from seeds or embryos infected with cherry leaf roll virus (CLRV), remained infected after culture at 22 oC. No infectivity was found in cultures held at 32 oC for 5 days but it was readily detected after such cultures were transferred to 25 oC for 8 days. Virus was permanently eradicated from most plants after 20 days incubation at 32 oC and from all plants after 7 days incubation at 40 oC.Partially purified preparations of CLRV lost infectivity after 9–12 days at 22oC, 5 days at 32oC and 3 days at 40oC.

Immunocapture-RT-PCR detection of Cassava common mosaic virus in cassava obtained from meristem-tip culture in Paraná state

“…However, meristem-tip cultures were effective for virus elimination in most of the plants as shown by PTA-ELISA (Table 1). It has been reported that heat treatment hampers virus replication and enhances virus disorganization, thus leading to the eradication of the virus from shoot tips (Cooper & Walkey, 1978). Recently, it was shown that viral RNA replication of Raspberry bushy dwarf virus (RBDV), a virus that enters meristematic tissues, was disorganized in leaves and shoot tips of plants growing at a high temperature (38 o C).…”

Review. Elimination of viruses in plants: twenty years of progress

“…Therefore, the outcome of therapeutic action is strongly influenced by the ontological properties of the virus to be eliminated as well as the characteristics expressed by the plant as well as the trans-membrane transport of drugs (Luvisi et al, 2012a;Rinaldelli et al, 2012). The application of chemotherapy or thermotherapy should aim at stopping the synthesis of new virions, but elimination can be achieved only if viral particles formed prior to treatment are completely eliminated, as suggested in research dated before 1991 (Kassanis, 1957;Cooper & Walker, 1978). For example, in many cases the chemotherapy target is an enzyme that can be efficiently blocked for the synthesis of new virus particles, but it is generally ineffective against already formed virus particles, which can only naturally degrade according to specific virus properties and host characteristics.…”

“…Kassanis (1949) provided an interpretation of the results obtained with the treatment, basing it on identification of the infected cell as the environment where virus particles are in a dynamic equilibrium between newly formed particles and degraded ones. Thermal treatment, therefore, produces a shift in this balance towards greater viral degradation which, when repeated over time, can lead to elimination (Kassanis, 1957;Cooper & Walker, 1978). The principal alterations in viral particles as a result of thermal treatment above 35°C are related to the rupture of hydrogen and disulfide bonds of capsid protein, followed by nucleic acid phosphodiester covalent bonds, and consequently, even deterioration of viral infectivity which can include selective inhibition of viral replicase, changes in pH and cellular ionic strength, increase of lytic enzymes, competition between viral RNA and messenger for ribosome bonds.…”

Enhanced efficiency of virus eradication following thermotherapy of shoot-tip cultures of pear

“…Heat treatment of plants in vivo/in vitro can reduce virus titers and improve the efficiency of virus eradication (Kassanis 1957;Mink et al 1998). Therefore, in vitro thermotherapy followed by meristem culture (Cooper and Walkey 1978;Cieślińska 2002;Manganaris et al 2003;Stein et al 1991;Walkey and Cooper 1975;Zilka et al 2002), shoot tip grafting (Sharma et al 2008) and also cryotherapy (Wang et al 2008(Wang et al , 2009) can markedly enhanced virus eradication. The efficiency of virus eradication by thermotherapy also depends on viruses, plant species and specific approaches.…”