Photosynthetic apparatus efficiency, phenolic acid profiling and pattern of chosen phytohormones in pseudometallophyte Alyssum montanum

Abstract

The present study investigated the response of non-metallicolous (NM) and metallicolous (M) Alyssum montanum shoots cultured in vitro on a medium supplemented simultaneously with heavy metals (HMs) to identify mechanisms involved in alleviating metal-induced damage. Plant status in respect to photosynthetic apparatus efficiency was determined and linked with changes in biochemical composition of shoots, namely phenolic acids’ and stress-related phytohormones. Results showed the considerable inter-ecotype differences in (1) the photosynthetic pigments’ amount, (2) the functioning of membrane electron transporters as well as (3) the linear and alternative electron transport pathways, whose lower values were reported in NM than in M HM-treated culture. Photosynthetic apparatus protection in M specimens was assured by the activation of cinnamic acid synthesis (by phenylalanine ammonia lyase) and its further transformations to benzoic acid derivatives with high ability to counteract oxidative stress, that was accompanied by the overexpression of jasmonic acid stimulating antioxidant machinery. In turn, detrimental HM effects on NM shoots could result from the diminution of most phenolics’ accumulation, and only the content of coumarate (produced by bifunctional phenylalanine/tyrosine ammonia lyase) and rosmarinic acid increased. All these together with an enhanced concentration of abscisic acid might suggest that NM strategy to cope with HMs is based mostly on a restriction of metal movement with transpiration flow and their limited distribution in leaves. Summarizing, our findings for the first time point out the physiological and metabolic adaptation of pseudometallophyte A. montanum to adverse conditions.

The Alleviation of Metal Stress Nuisance for Plants—A Review of Promising Solutions in the Face of Environmental Challenges

“…Although oxidative stress as a reaction to metals is one of the most studied issues recently [ 3 , 5 , 38 , 39 ], ROS transformation pathways, as a basis of adaptation to their excess amounts, have not been frequently compared between the representatives of different species sharing the same ecological niches or described for ecotypes of the same species representing different habitats. In this regard, our previous studies on serpentine and calamine ecotypes of Silene vulgaris (Caryophyllaceae) and the calamine ecotype of Alyssum montanum (Brassicaceae) have shown both species- and ecotype-dependent features [ 14 , 18 , 19 , 36 , 40 , 41 ]. The response of S. vulgaris to metallic elements was mainly related to the activity of antioxidant enzymes during in vitro cultivation on media enriched with Zn, Pb, and Cd at the same concentration as in the post-industrial habitat of the calamine ecotype [ 41 ].…”

“…The response of S. vulgaris to metallic elements was mainly related to the activity of antioxidant enzymes during in vitro cultivation on media enriched with Zn, Pb, and Cd at the same concentration as in the post-industrial habitat of the calamine ecotype [ 41 ]. In turn, the response of A. montanum was associated with the transformations of phenolic compounds, which, in the metallicolous ecotype, led to the synthesis of phenolic acids with a high ability to ROS scavenging and, in the non-metallicolous ecotype, to the synthesis of other compounds not involved in alleviating oxidative stress [ 19 ]. Interestingly, the common reaction of the metallicolous S. vulgaris and A. montanum individuals was the activity of GPX.…”

“…In the concentrations exceeding the maximum tolerable amount, they cause disturbances in the ultrastructure of cells and affect physiological and biochemical processes such as the biosynthesis of chlorophylls, photosynthetic capacity, transpiration, nutrient and water uptake, and the activity of enzymes involved in various metabolic pathways, as well as lead to increased ROS formation by direct involvement in redox reactions (in the case of highly reactive metals) or indirectly through depletion of antioxidant pools [ 5 , 9 , 14 , 15 , 16 , 17 ]. All these cellular effects result in morphological changes, such as shortening of shoots and roots, necrotic and chlorotic stains, decreases in leaf number and size, and premature aging [ 5 , 18 , 19 ]. As a consequence, it leads to limiting the productivity of agricultural crops [ 20 ].…”

In Vitro Culture as a Tool for Studying Plant Developmental Processes at the Physiological Level in Poland

“…ese two ecotypes were used in further in-depth research on the role of phenolic compounds and phytohormones in the defense mechanism against heavy metal ions that damage the photosynthetic apparatus (Muszyńska et al, 2021). For the M ecotype, these studies showed that jasmonic acid and flavonoids, which are involved in ROS scavenging, play an important role in the protection of photosystems, and the rearrangement of electron transport in thylakoid membranes.…”

The Different Faces of Arabidopsis arenosa—A Plant Species for a Special Purpose

“…Polyphenols, such as flavonols and anthocyanins, are generally recognized as molecules involved in stress protection in plants and have multiple functions in acclimation processes to an excessive amount of HMs [ 61 , 62 ]. It has been demonstrated in A. thaliana that anthocyanins play a major role in protecting against metal stresses [ 63 ].…”