Changes in protein methylation associated with the elicitation response in cell cultures of alfalfa (Medicago sativaL.)

Abstract

The methylation of endogenous proteins increased in alfalfa cell suspension cultures following treatment with a fungal elicitor. Carboxyl methylation, a post-translational modification associated with controlling the localisation and longevity of proteins, was the dominant form of protein methylation in both elicited and unelicited cells. Protein methylation was restricted to a limited number of peptides prior to elicitor treatment but as elicitation progressed the number of endogenous substrates increased. Increases resulted from a combination of an elicitordependent increase in the activity of a protein carboxyl methyltransferase and the accumulation of preferred endogenous substrates in the latter stages of elicitation.

Methylation reactions and the phytoalexin response in alfalfa suspension cultures

“…The major sink for the increased methylation was initially the production of antifungal isoflavonoid phytoalexins, though as elicitation progressed a significant amount of flux was diverted into the methylation of cell wall components, notably pectin. Further fractionation studies (data not shown) provided no evidence for elicitormediated increased methylation of DNA, RNA or other biochemically defined fractions other than a modest increase in protein methylation, as reported previously (Daniell and Edwards 1995). It can therefore be assumed that there are no other major metabolic sinks for the increased methylation during the phytoalexin response in alfalfa, apart from those described.…”

Towards molecular farming in the future: using plant‐cell‐suspension cultures as bioreactors

“…However, it is anticipated that the advances in the genetic engineering of plants and the demand for large quantities of new or improved diagnostics and therapeutics in the healthcare and pharmaceutical markets will lead to a rapid expansion in this research field. A number of plant species have been used for generation and propagation of cell-suspension cultures, ranging from model systems like Arabidopsis [8], Catharanthus [9] and Taxus [10], to important monocotyledon or dicotyledon crop plants like rice [11], soya bean [12], alfalfa [13] and tobacco [14].…”