Hydrogen peroxide induced by the fungicide prothioconazole triggers deoxynivalenol (DON) production by Fusarium graminearum

<p>Abstract</p> <p>Background</p> <p><it>Fusarium </it>head blight is a very important disease of small grain cereals with <it>F. graminearum </it>as one of the most important causal agents. It not only causes reduction in yield and quality but from a human and animal healthcare point of view, it produces mycotoxins such as deoxynivalenol (DON) which can accumulate to toxic levels. Little is known about external triggers influencing DON production.</p> <p>Results</p> <p>In the present work, a combined <it>in vivo/in vitro </it>approach was used to test the effect of sub lethal fungicide treatments on DON production. Using a dilution series of prothioconazole, azoxystrobin and prothioconazole + fluoxastrobin, we demonstrated that sub lethal doses of prothioconazole coincide with an increase in DON production 48 h after fungicide treatment. In an artificial infection trial using wheat plants, the <it>in vitro </it>results of increased DON levels upon sub lethal prothioconazole application were confirmed illustrating the significance of these results from a practical point of view. In addition, further <it>in vitro </it>experiments revealed a timely hyperinduction of H₂O₂production as fast as 4 h after amending cultures with prothioconazole. When applying H₂O₂directly to germinating conidia, a similar induction of DON-production by <it>F. graminearum </it>was observed. The effect of sub lethal prothioconazole concentrations on DON production completely disappeared when applying catalase together with the fungicide.</p> <p>Conclusions</p> <p>These cumulative results suggest that H₂O₂induced by sub lethal doses of the triazole fungicide prothioconazole acts as a trigger of DON biosynthesis. In a broader framework, this work clearly shows that DON production by the plant pathogen <it>F. graminearum </it>is the result of the interaction of fungal genomics and external environmental triggers.</p

The CEP5 Peptide Promotes Abiotic Stress Tolerance, As Revealed by Quantitative Proteomics, and Attenuates the AUX/IAA Equilibrium in Arabidopsis.

Peptides derived from non-functional precursors play important roles in various developmental processes, but also in (a)biotic stress signaling. Our (phospho)proteome-wide analyses of C-TERMINALLY ENCODED PEPTIDE 5 (CEP5)-mediated changes revealed an impact on abiotic stress-related processes. Drought has a dramatic impact on plant growth, development and reproduction, and the plant hormone auxin plays a role in drought responses. Our genetic, physiological, biochemical, and pharmacological results demonstrated that CEP5-mediated signaling is relevant for osmotic and drought stress tolerance in Arabidopsis, and that CEP5 specifically counteracts auxin effects. Specifically, we found that CEP5 signaling stabilizes AUX/IAA transcriptional repressors, suggesting the existence of a novel peptide-dependent control mechanism that tunes auxin signaling. These observations align with the recently described role of AUX/IAAs in stress tolerance and provide a novel role for CEP5 in osmotic and drought stress tolerance

Are the benefits of autonomy satisfaction and the costs of autonomy frustration dependent on individuals' autonomy strength?

OBJECTIVE: From a self-determination theory perspective, individuals are assumed to benefit and suffer from, respectively, the satisfaction and frustration of the psychological need for autonomy, even if they score low on autonomy strength. Yet, previous studies on need strength are scarce, operationalized need strength differently, and produced inconsistent findings. METHOD: In two studies among 224 South African adults (Mage  = 24.13, SD = 4.25; 54.0% male) and 156 Belgian prisoners (Mage  = 38.60, SD = 11.68; 88.5% male), we investigated the moderating role of autonomy valuation and desire in the relations of autonomy satisfaction and frustration with a variety of well-being and ill-being indicators. RESULTS: Study 1 provided some evidence for the moderating role of mostly explicit autonomy desire (rather than explicit autonomy valuation). In Study 2, neither explicit nor implicit autonomy desire played a consistent moderating role. CONCLUSIONS: Overall, these findings are congruent with a moderate (albeit not with a strong) interpretation of the universality claim made within self-determination theory, provide initial evidence for a differentiation between deficit-based and growth-oriented interpersonal differences in need strength, and indicate that the potential moderating role of need strength deserves continued attention before any firm conclusions can be drawn.status: publishe

The internalization of and defiance against rules within prison : the role of correctional officers’ autonomy-supportive and controlling communication style as perceived by prisoners

While incarcerated, prisoners are subject to a vast number of rules. Drawing upon self-determination theory, the present study examined whether prisoners’ perceptions of the degree to which prison officers communicate rules in an autonomysupportive or controlling way related to prisoners’ internalization of and defiance against rules, and whether this, in turn, related to their (mal)adaptive functioning in prison. Participants were 156 Belgian prisoners (Mage=38.60; SD=11.68, 88.5% male) who filled out questionnaires concerning the study variables. Associations were tested using structural equation modeling. Results showed that, whereas a higher level of perceived autonomy-supportive communication style related via greater internalization of rules to prisoners’ higher quality of life, a perceived controlling style was positively related to aggression and irritation vis-à-vis prison officers. Additional analyses suggested that an alternative model, where prisoners’ maladaptive functioning is predictive of higher levels of perceived controlling communication, is equally valid