Matern, S. | Search bioRxiv

bioRxiv2024

MAPK activity and MAP kinase phosphatase 2 (AtMKP2) protein stability under altered glutathione homeostasis in Arabidopsis thaliana

Mitogen-activated protein kinases (MAPKs) are important signaling players involved in various responses to diverse environmental stresses. MAP kinase phosphatases (MKPs) are crucial negative regulators of MAPKs and control the intensity and duration of MAPK activation. It has been shown that transgenic tobacco plants with increased glutathione content display an oxidative shift and have constitutively active immunity-related MAPKs. The mechanism by which glutathione can activate or keep these MAPKs in activated state is unclear. In this study, it is shown that the Arabidopsis stress-related MAPKs, AtMPK3 and AtMPK6 are hypersensitive to a pathogen-associated molecular pattern flg22 in the cat2-1 line, under the conditions causing an altered glutathione homeostasis and elevated oxidative stress responses in this background. As AtMKP2 is the only dual specificity phosphatase deactivating AtMPK3 and AtMPK6 in response to oxidative stress, the stability of the wild-type AtMKP2 protein and the mutant version of the protein with the substitution of the cys109 in the active site with serine has been studied in wild type (Col-0) and cat2-1 background. The results indicate that AtMKP2 is a stable protein in both genetic backgrounds, whereas the active site cys109 stabilizes the protein under severe oxidative stress conditions and can be glutathionylated in vitro.

plant biology↗

bioRxiv2018

Impact of recreational fisheries management on fish biodiversity in gravel pit lakes with contrasts to unmanaged lakes

Gravel pit lakes constitute novel ecosystems that can be colonized by fishes through natural or anthropogenic pathways. Many of these man-made lakes are used by recreational anglers and experience regular fish stocking. Recreationally unmanaged gravel pits may also be affected by fish introductions, e.g., through illegal fish releases, thereby contributing to the formation of site-specific communities. Our objective was to compare the fish biodiversity in gravel pit lakes with and without the recent influence of recreational fisheries management. We sampled 23 small (< 20 ha) gravel pit lakes (16 managed and 7 unmanaged) in north-western Germany and compared fish community and diversity metrics obtained using littoral electrofishing and multimesh gillnet catch per unit effort data. Given the size of the lakes we sampled we expected species poor communities and elevated fish diversity in the managed systems due to stocking. The two lake types were primarily mesotrophic and did not differ in key abiotic and biotic environmental characteristics. Both lakes types hosted similar fish abundance and biomass, but were substantially different in terms of the fish community structure and species richness. Fish were present in all lakes with at least three species. We discovered a higher -diversity and a lower {beta}-diversity in managed gravel pit lakes compared to unmanaged lakes. Thus, recreational fisheries management appeared to foster homogenization of fish communities, likely because fisheries managers stock these lakes with desired fish species (e.g., piscivorous fishes and large bodied cyprinids). However, we also detected anthropogenic pathways in the colonization of unmanaged gravel pit lakes, presumably from illegal releases by private people. Importantly, hardly any non-native species were detected in the gravel pits we studied, suggesting that recreational fisheries management not necessarily promotes the spread of exotic species.\n\nSignificance StatementLittle is known about fish communities in artificially created gravel pit lakes. We compared those managed by recreational fishers with those lacking fisheries management in north-western Germany. We found fishes in all gravel pit lakes and demonstrated a higher -diversity but more homogenized fish communities in managed gravel pit lakes compared to unmanaged lakes. We did not detect the establishment of relevant abundances of non-natives fishes despite intensive fisheries management.

ecology↗