Genome-wide association analysis of potassium uptake and translocation rates under low K stress in Tibetan wild barley
EUPHYTICA
Authors: Ye, Zhilan; Zeng, Jianbin; Ye, Lingzhen; Long, Lizhi; Zhang, Guoping
Abstract
A low level of available potassium (K) in soils is a major factor restricting crop growth and production. In earlier studies we found that Tibetan wild barley has a wider variation in low K stress tolerance than cultivated barley. In this study, we performed a genome-wide association analysis of 179 Tibetan wild barley (Hordeum vulgare L.) accessions exposed to low K stress and investigated the associations of K uptake rate (KUR), K translocation rate (KTR) and other K metabolism traits with 11,013 diversity arrays technology markers. The results showed that there were significant differences in tissue K concentration and content, KUR and KTR among the wild barley accessions analyzed. Scores for all traits showed a normal distribution. Three significant quantitative trait loci (QTLs) for KUR and KTR were identified and located on 6H and 1H. These QTLs were found to be associated with the cation/H(+) antiporter and cyclic nucleotide gated channel. A number of unique candidate genes associated with K-related signals, including K channels, K transporters and ethylene-related genes, were also identified. The K channels and K transporters involved in K uptake and translocation, respectively, were closely associated with KUR in response to low K stress. The present study highlights the potential of Tibetan wild barley to provide elite candidate genes for the improvement of K use efficiency of barley.
Insulin and Exendin-4 Reduced Mutated Huntingtin Accumulation in Neuronal Cells
FRONTIERS IN PHARMACOLOGY
Authors: Rea, Silvia; Della-Morte, David; Pacifici, Francesca; Capuani, Barbara; Pastore, Donatella; Coppola, Andrea; Arriga, Roberto; Andreadi, Aikaterini; Donadel, Giulia; Di Daniele, Nicola; Bellia, Alfonso; Lauro, Davide
Abstract
Patients with diabetes mellitus (DM) are more prone to develop cognitive decline and neurodegenerative diseases. A pathological association between an autosomal dominant neurological disorder caused by brain accumulation in mutated huntingtin (mHTT), known as Huntington disease (HD), and DM, has been reported. By using a diabetic mouse model, we previously suggested a central role of the metabolic pathways of HTT, further suggesting the relevance of this protein in the pathology of DM. Furthermore, it has also been reported that intranasal insulin (Ins) administration improved cognitive function in patients with neurodegenerative disorders such as Alzheimer disease, and that exendin-4 (Ex-4) enhanced lifespan and ameliorated glucose homeostasis in a mouse model of HD. Although antioxidant properties have been proposed, the underlying molecular mechanisms are still missing. Therefore, the aim of the present study was to investigate the intracellular pathways leading to neuroprotective effect of Ins and Ex-4 hypoglycemic drugs by using anin vitromodel of HD, developed by differentiated dopaminergic neurons treated with the pro-oxidant neurotoxic compound 6-hydroxydopamine (6-ohda). Our results showed that 6-ohda increased mHTT expression and reduced HTT phosphorylation at Ser421, a post-translational modification, which protects against mHTT accumulation. Pre-treatment with Ins or Ex-4 reverted the harmful effect induced by 6-ohda by activating AKT1 and SGK1 kinases, and by reducing the phosphatase PP2B. AKT1 and SGK1 are crucial nodes on the Ins activation pathway and powerful antioxidants, while PP2B dephosphorylates HTT contributing to mHTT neurotoxic effect. In conclusion, present results highlight that Ins and Ex-4 may counteract the neurotoxic effect induced by mHTT, opening novel pharmacological therapeutic strategies against neurodegenerative disorders, with the main focus on HD, still considered an orphan illness.