The plant hormone indole-3-acetic acid (IAA) is one of the main signals playing a role in the communication between host and endophytes. Endophytes can synthesize IAA de novo to influence the IAA homeostasis in plants. Although much is known about IAA biosynthesis in microorganisms, there is still less known about the pathway by which IAA is synthesized in fungal endophytes. The aim of this study is to examine a possible IAA biosynthesis pathway in Cyanodermella asteris. In vitro cultures of C. asteris were incubated with the IAA precursors tryptophan (Trp) and indole, as well as possible intermediates, and they were additionally treated with IAA biosynthesis inhibitors (2-mercaptobenzimidazole and yucasin DF) to elucidate possible IAA biosynthesis pathways. It was shown that (a) C. asteris synthesized IAA without adding precursors; (b) indole-3-acetonitrile (IAN), indole-3-acetamide (IAM), and indole-3-acetaldehyde (IAD) increased IAA biosynthesis; and (c) C. asteris synthesized IAA also by a Trp-independent pathway. Together with the genome information of C. asteris, the possible IAA biosynthesis pathways found can improve the understanding of IAA biosynthesis in fungal endophytes. The uptake of fungal IAA into Arabidopsis thaliana is necessary for the induction of lateral roots and other fungus-related growth phenotypes, since the application of the influx inhibitor 2-naphthoxyacetic acid (NOA) but not the efflux inhibitor N-1-naphtylphthalamic acid (NPA) were altering these parameters. In addition, the root phenotype of the mutation in an influx carrier, aux1, was partially rescued by C. asteris.

OBJECTIVE Insulin recruits muscle microvasculature, thereby increasing endothelial exchange surface area. Free fatty acids (FFAs) cause insulin resistance by activating inhibitor of κB kinase β. Elevating plasma FFAs impairs insulin’s microvascular and metabolic actions in vivo. Whether salsalate, an anti-inflammatory agent, prevents FFA-induced microvascular and/or metabolic insulin resistance in humans is unknown. RESEARCH DESIGN AND METHODS Eleven healthy, young adults were studied three times in random order. After an overnight fast, on two occasions each subject received a 5-h systemic infusion of Intralipid ± salsalate pretreatment (50 mg/kg/day for 4 days). On the third occasion, saline replaced Intralipid. A 1 mU/kg/min euglycemic insulin clamp was superimposed over the last 2-h of each study. Skeletal and cardiac muscle microvascular blood volume (MBV), microvascular flow velocity (MFV), and microvascular blood flow (MBF) were determined before and after insulin infusion. Whole body glucose disposal rates were calculated from glucose infusion rates. RESULTS Insulin significantly increased skeletal and cardiac muscle MBV and MBF without affecting MFV. Lipid infusion abolished insulin-mediated microvascular recruitment in both skeletal and cardiac muscle and lowered insulin-stimulated whole body glucose disposal (P < 0.001). Salsalate treatment rescued insulin’s actions to recruit muscle microvasculature and improved insulin-stimulated whole body glucose disposal in the presence of high plasma FFAs. CONCLUSIONS High plasma concentrations of FFAs cause both microvascular and metabolic insulin resistance, which can be prevented or attenuated by salsalate treatment. Our data suggest that treatments aimed at inhibition of inflammatory response might help alleviate vascular insulin resistance and improve metabolic control in patients with diabetes.

Cyanodermella asteris is a fungal endophyte from Aster tataricus, a perennial plant from the Northern part of Asia. Here, we demonstrated an interaction of C. asteris with Arabidospis thaliana, Chi...

Flooding is becoming more frequent and severely affects agricultural production, however, compared to other stressors in plants, the underlying stress management mechanisms are largely underexplored. Using chromatographic (GC-MS, LC-MS) and spectrophotometric analyses, we assessed the impact of long-term (i.e., 24 days) waterlogging on seven Brassica oleracea varieties that belong to different vegetable forms. The response of the metabolism was analysed by assessing the levels of phytohormones, polyphenols, and glucosinolates, and was linked with the impact on stress biomarkers and antioxidative systems. The major outcome of this research is the observed high variety-specific response to waterlogging. Savoy cabbage displayed more severe alterations in its specialised metabolism, which may have been mediated by indole-3-acetic acid (IAA). The expression of the corresponding biosynthesis genes was shown to be linked with changes in metabolic parameters. Modifications in phenolic metabolism pathways affected the antioxidative capacity and potentially influenced the gene expression of genes encoding antioxidative enzymes. The variable effects of waterlogging may indicate the potential of certain specialised metabolite groups as biomarkers for such stress conditions in Brassica plants that can be used to guide future agricultural practices. Furthermore, new insights into the underlying processes of waterlogging stress could aid future studies aimed at strengthening plant stress resilience in the era of severe climate change.