<i>Arabidopsis thaliana</i> transcription factors <i>MYB28</i> and <i>MYB29</i> shape ammonium stress responses by regulating Fe homeostasis

15 Pág.Although ammonium (NH4+ ) is a key intermediate of plant nitrogen metabolism, high concentrations of NH4+ in the soil provoke physiological disorders that lead to the development of stress symptoms. Ammonium nutrition was shown to induce the accumulation of glucosinolates (GSLs) in leaves of different Brassicaceae species. To further understand the link between ammonium nutrition and GSLs, we analysed the ammonium stress response of Arabidopsis mutants impaired in GSL metabolic pathway. We showed that the MYB28 and MYB29 double mutant (myb28myb29), which is almost deprived of aliphatic GSLs, is highly hypersensitive to ammonium nutrition. Moreover, we evidenced that the stress symptoms developed were not a consequence of the lack of aliphatic GSLs. Transcriptomic analysis highlighted the induction of an iron (Fe) deficiency response in myb28myb29 under ammonium nutrition. Consistently, ammonium-grown myb28myb29 plants showed altered Fe accumulation and homeostasis. Interestingly, we showed overall that growing Arabidopsis with increased Fe availability relieved ammonium stress symptoms and that this was associated with MYB28 and MYB29 expression. Taken together, our data indicated that the control of Fe homeostasis was crucial for the Arabidopsis response to ammonium nutrition and evidenced that MYB28 and MYB29 play a role in this control.The research leading to these results has received funding from the Basque Government, IT-932-16 (IC, IB, DM) and the Spanish Government, BIO2014-56271-R and BIO2017-84035-R, both co-funded by FEDER (IC, IB, DM). IB holds a fellowship from the Basque Government. This work was further supported by the Danish National Research Foundation, DNRF grant 99 (MB) and the Danish Council for Independent Research, DFF-4181-00077 (CR, MB). This work was also supported by the National Institute for Agriculture and Food Research and Technology, RTA2015-00014-c02-01 (JM). We thank John Celenza for providing seeds for the cyp79b2b3 mutant, George Jander for the tgg1tgg2 mutant, Masami Hirai for the myb28myb29 mutant and Andrea Chini for the myc234 mutant. The authors thank the technical and human support provided by SGIker (UPV/EHU).Peer reviewe

Conceptions of Crisis Management Capabilities – Municipal Officials’ Perspectives

In the Swedish crisis management system, the municipalities have a great responsibility. One part of this responsibility concerns preparing for crises by making risk and vulnerability analyses as well as plans for how to handle extraordinary events. Such preparedness planning involves municipal officials and consequently their conceptions of their organisations’ crisis management capabilities. This makes it vital to look into these conceptions more closely and establish whether specific characteristics can be identified. This thesis aims at gaining understanding of how officials involved in preparedness planning in general and vulnerability analysis in particular explicitly conceive of their organisations’ crisis management capabilities. The thesis poses six specific research questions, pertaining to three themes: vulnerability, dependencies and learning. The results show specific characteristics in how officials conceive of their organisations’ crisis management capabilities. These characteristics appear as similarities, variations, and even disagreements. It is argued that the characteristics as well as what explains them must be considered in the development of society’s crisis management systems

Additional file 1: Figure S1. of Leaves play a central role in the adaptation of nitrogen and sulfur metabolism to ammonium nutrition in oilseed rape (Brassica napus)

Biomass of B. napus plants cultured with 1, 2.5 and 5 mM nitrate or ammonium. Values represent mean ± SE (n = 16 individual plants). Different letters indicate statistical differences between treatments (ANOVA analysis with Duncan’s test, P < 0.05). Asterisk (*) indicates significant nitrogen source effect within each nitrogen concentration (t-test, P < 0.05). (PDF 57 kb

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

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