Ecological implication of variation in the secondary metabolites in Parmelioid lichens with respect to altitude

Abstract

Lichens are known to synthesize a variety of secondary metabolites having multifunctional activity in response to external environmental condition. Two common lichen extrolites, atranorin and salazinic acid, are known to afford antioxidant as well as photoprotectant nature depending on the abiotic/biotic stress. The present investigation aims to study the influence of altitudinal gradient on the quantitative profile of atranorin and salazinic acid in three lichen species, Bulbothrix setschwanensis (Zahlbr.) Hale, Everniastrum cirrhatum (Fr.) Hale and Parmotrema reticulatum (Taylor) Choisy, Parmeliaceae using liquid chromatography-mass spectrometry (LC-MS/MS) technique. Samples were collected from high-altitude area, usually considered as non-polluted sites of Garhwal Himalaya. Characterization and quantification of the lichen substances in samples were carried out comparing with the standards of atranorin and salazinic acid. Results indicated significant variation in the chemical content with the rising altitude. All the three lichen species showed higher quantities of chemical substances with the altitudinal rise, while among the three lichen species, E. cirrhatum showed the highest quantity of total lichen compounds. The higher abundance and frequency of E. cirrhatum with increasing altitude as compared to B. setschwanensis and P. reticulatum may be attributed due to the presence of higher quantity of photoprotecting/antioxidant chemicals especially salazinic acid. Thus, the present study shows the prominent role of secondary metabolite in wider ecological distribution of Parmelioid lichens at higher altitudes.

UPLC–MS/MS quantitative analysis and structural fragmentation study of five Parmotrema lichens from the Eastern Ghats

“…However, most of these tests have some limits to distinguish minute differences between species [9]. Alternatively, study of lichen compounds by usual LC-MS techniques [10] or direct spectroscopic analysis [11][12][13][14][15][16][17] offers a helpful tool for chemotaxonomic determination of compounds and dereplication strategies [18,19]. Accurate techniques as UPLC-HRMS are now available to identify a number of compounds [20][21][22][23] but protocols are not still standardized.…”

Diversity of Secondary Metabolites in the Liverwort Syzygiella rubricaulis (Nees) Stephani (Jamesoniellaceae, Marchantiophyta) from Neotropical High Mountains

“…The increased solar radiation and the lower temperature at higher altitudes are assumed to have the most profound influence on plant secondary metabolism. [17] [18] However, the altitude, by itself, is not related to the richness of substances found in the 12 studied populations (r = 0.29). Beyond the altitude, several other environmental factors, not measured here, such as precipitation, temperature, soil type, wind speed, temperature, snow-cover, vegetation, and radiation differ, can supposedly vary in their collected sites.…”

“…The increased solar radiation and the lower temperature at higher altitudes are assumed to have the most profound influence on plant secondary metabolism . However, the altitude, by itself, is not related to the richness of substances found in the 12 studied populations ( r = 0.29).…”

Effect of UV‐B radiation on the content of UV‐B absorbing compounds and photosynthetic parameters in Parmotrema austrosinense from two contrasting habitats

“…Shukla et al . () investigated protective secondary compounds in P. reticulatum in relation with microclimate factors related to altitude. Similarly, Armaleo et al .…”

“…Sensitivity to other ecological factors, however, has been scarcely studied. Shukla et al (2016) investigated protective secondary compounds in P. reticulatum in relation with microclimate factors related to altitude. Similarly, Armaleo et al (2008) focused on light intensity effects on depsides and depsidones in P. hypotropum.…”