Virus Resistance Induced with Mannan Sulphates in Hypersensitive Host Plants

Abstract

Mannan sulphates (MS), obtained by sulphatation of extracellular linear mannan (LM) from Rhodotorula rubra, induced resistance to tobacco mosaic virus (TMV) in hypersensitive plants, retained in isolated protoplasts. MS‐induced resistance in tobacco is accompanied by a marked increase of lytic processes in cells and a decrease of total (acidic and alkaline) protein content. In addition to this, new protein components, including PR‐proteins and antiviral substances, of the inhibitor of virus replication (IVR) type, appeared in treated plant tissues. MS‐induced resistance resembles localized resistance induced by TMV in hypersensitive tobacco plants and could serve as an experimental model for study of the latter.

Novel disease control compounds: the potential to ‘immunize’ plants against infection

“…The optimum dose of UV irradiation used by Mercier et al was 2 20 x 10^ erg/cmŜ emi-synthetic elicitors Semi-synthetic elicitors are chemically modified biotic compounds. For example, the natural linear mannan from Rhodotorula rubra (Kovalenko et al, 1993) has no elicitor activity, but sulphated forms have antiviral activity which appears to work via an induction of host defence responses such as PR proteins. Unfortunately, these mannan sulphates are also phytotoxic and therefore have little practical potential.…”

Plant virus inhibitors from marine algae

“…Despite the popularity of this charge mediated mode of action, there is strong evidence that it may not be the only antiviral effect that polysaccharides exert. In the past 8 years several studies have found polysaccharides to elicit plant defences and induce systemic acquired resistance (SAR) to crop pathogens Mercier et al, 2001;Kovalenko et al, 1993). Some algal polysaccharides, for example krninarin, are capable of mimicking natural elicitors, which upon recognition at the surface of the host cell stimulate the expression of plant defence genes (Mercier et al, 2001).…”

“…These effects appear to be widespread, having been induced in assays using wheat, soyabean, alfalfa and tobacco. To date most studies have focused on testing resistance to the two most costiy crop pathogens, fungi and viruses Mercier et al, 2001;Kovalenko et al, 1993).…”

Discovery of lectin-like proteins in the tobacco and datura plants, infected by tobacco mosaic virus

“…Для вивчення клітинної локалізації речовин, що мають антивірусну і гемаглютинуючу актив ності, ФБС-екстракти з ураженого (7 діб після інокуляції ВТМ) та здорового листя розділяли на розчинну (105000 g -супернатант), мікросомнорибосомну (105000 g -осад) та ядерно-хлоропластно-мітохондріальну фракції (17000 g -осад) за допомогою диференційного центрифугування, як описано в роботі [11]. Солюбілізацію структурно зв'язаних компонентів з органел здійснювали 1 %м розчином тритону Х-100 в 0,1 М ФБС, рН 7,4.…”