Characterization of surface n-alkanes and fatty acids of the epiphytic lichen Xanthoria parietina, its photobiont a green alga Trebouxia sp., and its mycobiont, from the Jerusalem hills

Abstract

Surface alkanes and fatty acids from the thalli of the lichen Xanthoria parietina, its photobiont Trebouxia sp., and its mycobiont were analysed by GC-MS. The green alga Trebouxia sp. synthesized mainly unsaturated fatty acids such as (Z,Z,Z)-9,12,15-18:3 (Z,Z)-9,12-18:2 and (Z)-9-18:1, and light alkanes C8-C15 (up to 83% of total n-alkanes). However, the mycobiont contained mainly saturated fatty acids such as hexadecanoic (16:0) and octadecanoic acid (18:0), and also very long-chain n-alkanes C22-C34. Dehydroabietic acid was found in both lichen and mycobiont. The occurrence of different amounts of n-alkanes and fatty acids in the photobionts and mycobionts of X. parietina was shown for the first time. Lichens collected from different locations in the Jerusalem hills contained n-alkanes ranging in concentration from 187 to 211 mg·(g dry wt)-1; n-alkane concentrations in the photobiont and mycobiont were 17-24 and 215-262 mg·(g dry wt)-1, respectively.