Reorganization of Protein Tyrosine Nitration Pattern Indicates the Relative Tolerance of Brassica napus (L.) over Helianthus annuus (L.) to Combined Heavy Metal Treatment

Abstract

Metal-polluted areas, especially where municipal sewage is used as fertilizer, often have high concentrations of more than one metal. The development of the root system is regulated by a complex signaling network, which includes reactive oxygen and nitrogen species. The delicate balance of the endogenous signal system can be affected by various environmental stimuli including heavy metals (HMs) in excess. Our goal was to analyze the microelement homeostasis, root architecture, and to determine the underlying changes in the nitro-oxidative status in the root system of rapeseed (Brassica napus L.) and sunflower (Helianthus annuus L.) subjected to combined HM treatments. The effect of model-sewage in two different layouts was simulated in rhizotron system by only supplementing the highest HM concentrations (Cd, Cr, Cu, Hg, Ni, Pb, and Zn) legally allowed. The two species reacted differently to combined HM treatment; compared to the relatively sensitive sunflower, rapeseed showed better metal translocation capability and root growth even at the more severe treatment, where the pattern of protein tyrosine nitration was reorganized. The obtained results, especially the increased nitric oxide content and changed pattern of tyrosine nitration in rapeseed, can indicate acclimation and species-specific nitro-oxidative responses to combined HM stress.

Phytotoxicity evaluation of nutrient-fortified pomegranate peel powders prepared from food waste and their feasibility as biofertilizers

“…The results of Western blotting revealed protein tyrosine nitration, which is a nitro-oxidative stress-induced post-translational modification, in Brassica root tissues after 32 days of cultivation. Depending on the level of reactive oxygen and nitrogen species, tyrosinenitrated proteins are formed through various physiological and pathological processes, and therefore, provide valuable information on the stress state of plants (Feigl et al, 2020).…”

“…In plants subjected to heavy metal stress, the level of protein tyrosine nitration is often increased, indicating a state of stress (Gzyl et al, 2016;Feigl et al, 2015Feigl et al, , 2016Feigl et al, , 2019Feigl et al, , 2020Kolbert et al, 2020). However, the simultaneous appearance and disappearance of immunopositive bands result in a changed pattern of protein tyrosine nitration and can demonstrate a tolerance mechanism to heavy metal exposure (Feigl et al, 2019(Feigl et al, , 2020.…”

Different Nitro-Oxidative Response of Odontarrhena lesbiaca Plants from Geographically Separated Habitats to Excess Nickel

“…In this case, the re-orientation of the lateral roots to a more horizontal direction seems to support the relative Ni tolerance of plants originated from the Ampeliko site compared to Loutra. However, it has to be noted that changes in the lateral root angle due to heavy metal stress seem to be species-specific, since the root growth of sunflower (Helianthus annuus) was significantly inhibited by combined heavy metal treatment, but the orientation of its lateral roots changed to a more horizontal direction as well [39].…”

“…Antioxidants 2020, 9, x FOR PEER REVIEW 7 of 13 in a much lower concentration: approximately 160 ppm Ni caused 50% growth inhibition, while 200 ppm almost inhibited root growth completely (Figure S2). Orientation of the lateral roots might be in connection with the degree of stress and the tolerance of the plant against it [39,49]. In the present experimental setup, in the case of the more tolerant O. lesbiaca plants from the Ampeliko site, the angle of the lateral roots enclosed with the primary root changed to the horizontal direction (from 52° to 57°; Figure S3), while in the more sensitive plants from the Loutra site showed no such response (remained around 55°).…”

“…Heavy metals are reportedly able to induce protein tyrosine nitration. It was detected in soybean as the effect of cadmium [36], in Brassica napus and B. juncea in the presence of excess zinc [37,38], or in case of combined heavy metal exposure in B. napus and Helianthus annuus [39]. It was also induced by Ni in the non-hyperaccumulator Arabidopsis thaliana and B. juncea [29], but so far, we have no information regarding the nitro-oxidative response of any Ni hyperaccumulator plant species.…”