Effects of n-propyl gallate on photosynthesis and physiological parameters in Dunaliella salina are affected by stressful conditions

Abstract

We studied the effects of n-propyl gallate, which is a plastid terminal oxidase inhibitor involved in chlororespiration, on photosynthesis and physiological parameters in Dunaliella salina grown under different salinities and under low or high irradiance using chlorophyll a fluorescence transient measurements and pigment analysis. The inhibitor up to 1 mM had an additive significant effect on the photosynthetic efficiency in the cell suspensions grown under low salinity and irradiance. However, in the presence of high n-propyl gallate concentration (4 mM), there was a negative effect on all physiological aspects. In contrast, this high concentration of the inhibitor could enhance efficiency of electron transport and growth parameters under high irradiance. On the other hand, with salinity increase, the unfavorable effects of high inhibitor concentration on the efficiency of photosystem II were less evident than of low salinity. Interestingly, n-propyl gallate high concentration had a positive effect on fluorescence and on physiological parameters when high salinitiesgrown cells were exposed to high irradiance. The results suggest that there is a rational correlation between increase of salinity and algae ability to bypass n-propyl gallate inhibited plastid terminal oxidase function and also direct influence of its lethal concentration on photosystem II compartment. The ability is especially substantial when the increase of salinity is accompanying high irradiance. Furthermore, these data show that algal responses to inhibitor concentrations are different under various environmental conditions.

Metabolic responses and β-carotene production by the unicellular green alga Dunaliella salina exposed to leaf extracts

“…Thus, it is probably that the leaf extracts-induced β-carotene concentration increase could be brought about maintenance of Chl, in addition to its biosynthesis stimulation under leaf extracts-induced stress. It is in agreement with our previous results on propyl gallateinduced β-carotene under salt stress (Einali & Shariati 2012;Einali & Valizadeh 2015). Based on the results, the highest concentrations of both Chl and β-carotene were observed in cells exposed to 1 % eucalyptus and 2 % elderberry (Figs.…”

“…It is known that Dunaliella accumulate large amount of β-carotene while cell division is retard. Thus, adverse environmental conditions, such as high salinity, low temperature, high irradiance, or nutrient deficiency increase the accumulation of β-carotene in this alga (BenAmotz et al 1982;Ben-Amotz & Avron 1983;Ben-Amotz 1996;Einali & Shariati 2012;Einali & Valizadeh 2015). Due to that, Dunaliella has been widely considered as an interesting model for studying β-carotene biosynthesis.…”

Sensitivity of Antarctic freshwater algae to salt stress assessed by fast chlorophyll fluorescence transient

“…Kalaji et al 2011, Bacarin et al 2011, however only limited number of studies used PI abs as indicator in stress physiology of algae (e.g. Einali et Shariati 2012, Zhou et al 2013) and cyanobacteria (e.g. Bueno et al 2004, Zhang et al 2010).…”

Propyl gallate promotes salt stress tolerance in green microalga Dunaliella salina by reducing free radical oxidants and enhancing β-carotene production

“…In addition to antioxidative activity, other PG biological characteristics have also been demonstrated, such as anticancer, antifungal, and antibacterial properties (kratz et al 2008). It is frequently used as a specific inhibitor of plastid terminal oxidase (PTOX) involved in chlororespiration, in photosynthetic investigations (Cournac et al 2000;Kuntz 2004;Gamboa et al 2009;Einali and Shariati 2012). Our recent study displayed that PG concentration of 1 mM leads to an increase in pigment content and improvement of the efficiency of photosystem II in D. salina (Einali and Shariati 2012).…”

“…It is frequently used as a specific inhibitor of plastid terminal oxidase (PTOX) involved in chlororespiration, in photosynthetic investigations (Cournac et al 2000;Kuntz 2004;Gamboa et al 2009;Einali and Shariati 2012). Our recent study displayed that PG concentration of 1 mM leads to an increase in pigment content and improvement of the efficiency of photosystem II in D. salina (Einali and Shariati 2012). Other studies have shown that exogenous utilization of some antioxidants and signal molecules, such as ascorbate and salicylic acid, can induce the antioxidant systems and enhance plant resistance against abiotic stress (Li et al 1998;He et al 2002;Athar et al 2008;Saruhan et al 2012).…”