A glycoconjugate from corms of saffron plant (Crocus sativus L.) inhibits root growth and affects in vitro cell viability

A glycoconjugate has been characterized from saffron corms (Crocus sativus L,) that inhibits the growth of roots of Nicotiana tabacum and Arabidopsis thaliana, at concentrations ranging from 1-100 mu g m(-3). Roots of seedlin gs grown in the presence 0.1 mu g m(-3) glycoconjugate showed bulging of ep idermal cells, whereas at 10 mu g m(-3), roots were completely devoid of ha irs. At 100 mu g m(-3) glycoconjugate the cell walls of the root vascular t issues were thicker and, overall, the vascular tissue was enlarged. In addi tion, this glycan is cytotoxic to isolated tobacco cells and protoplasts, w ith 50% cell death induced by 0.5 and 2 mu g m(-3) glycoconjugate, respecti vely, Morphological and biochemical changes induced by the exposure to the glycoconjugate included cell size decrease, loss of regular cell shape, cyt oplasm collapse, and release of intracellular proteins. This molecule at lo w concentrations (0.1 mu g m(-3)) mimics the effects of Yariv phenylglycosi des and of mutant Arabidopsis which present defective or missing arabinogal actan-proteins (AGPs) in roots, indicating the glycoconjugate might interac t with cell surface AGPs.