Aluminium-induced phospholipid signal transduction pathway in Coffea arabica suspension cells and its amelioration by silicic acid

摘要

Coffee (Coffea arabica L.) is of economic importance worldwide. Its growth in organic-rich acidic soils is influenced by aluminium such that coffee yield may be impaired. Herein we have used the Al-sensitive C. arabica suspension cell line L2 to analyse the effect of two different At species on the phosphoinositide signal transduction pathway. Our results have shown that the association of At with coffee cells was affected by the pH and the form of At in media. More At was associated with cells at pH 4.3 than 5.8, whereas when At was present as hydroxyalummosilicates (HAS) the association was halved at pH 4.3 and unchanged at pH 5.8. Two signal transduction elements were also evaluated; phospholipase C (PLC) activity and phosphatidic acid (PA) formation. PLC was inhibited (similar to 50%) when cells were incubated for 2 h in the presence of either AlCl3 or At in the form of HAS. PA formation was tested as a short-term response to Al. By way of contrast to what was found for PLC, incubation of cells for 15 min in the presence of AlCl3 decreased the formation of PA whereas the same concentration of At as HAS produced no effect upon its formation. These results suggest that At is capable to exert its effects upon signal transduction as Al-(aq)(3+) acting upon a mechanism linked to the phosphoinositide signal transduction pathway. (c) 2006 Elsevier Inc. All rights reserved.