Peroxidase gene TaPrx109-B1 enhances wheat tolerance to water deficit via modulating stomatal density.

Increasing the tolerance of crops to water deficit is crucial for the improvement of crop production in water-restricted regions. Here, a wheat peroxidase gene (TaPrx109-B1) belonging to the class III peroxidase gene family was identified and its function in water deficit tolerance was revealed. We demonstrated that overexpression of TaPrx109-B1 reduced leaf H2O2 level and stomatal density, increased leaf relative water content, water use efficiency, and tolerance to water deficit. The expression of TaEPF1 and TaEPF2, two key negative regulators of stomatal development, were significantly upregulated in TaPrx109-B1 overexpression lines. Furthermore, exogenous H2O2 downregulated the expression of TaEPF1 and TaEPF2 and increased stomatal density, while exogenous application of diphenyleneiodonium chloride, a potent NADPH oxidase inhibitor that repressed the synthesis of H2O2, upregulated the expression of TaEPF1 and TaEPF2, decreased stomatal density, and enhanced wheat tolerance to water deficit. These findings suggest that TaPrx109-B1 influences leaf stomatal density by modulation of H2O2 level, and consequently affecting the expression of TaEPF1 and TaEPF2. The results of the field trial showed that overexpressing TaPrx109-B1 increased grain number per spike, which reduced the yield loss caused by water deficiency. Therefore, TaPrx109-B1 has great potential in breeding wheat varieties with improved water deficit tolerance.

Genome-Wide Identification of TaSAUR Gene Family Members in Hexaploid Wheat and Functional Characterization of TaSAUR66-5B in Improving Nitrogen Use Efficiency.

Excessive input of nitrogen fertilizer not only causes a great waste of resources but brings about a series of ecological and environmental problems. Although Small Auxin Up-regulated RNAs (SAURs) participate in diverse biological processes, the function of SAURs in the nitrogen starvation response has not been well-studied. Here, we identified 308 TaSAURs in wheat and divided them into 10 subfamilies. The promoter regions of most TaSAURs contain hormone responsive elements, and their expression levels change under the treatment of different hormones, such as IAA, MeJA, and ABA. Interestingly, overexpression of one of the TaSAUR family members, a nitrogen starvation responsive gene, TaSAUR66-5B, can promote the growth of Arabidopsis and wheat roots. In addition, overexpression of TaSAUR66-5B in Arabidopsis up-regulates the expression levels of auxin biosynthesis related genes, suggesting that overexpression TaSAUR66-5B may promote root growth by increasing the biosynthesis of auxin. Furthermore, overexpression of TaSAUR66-5B in wheat can increase the biomass and grain yields of transgenic plants, as well as the nitrogen concentration and accumulation of both shoots and grains, especially under low nitrogen conditions. This study provides important genomic information of the TaSAUR gene family and lays a foundation for elucidating the functions of TaSAURs in improving nitrogen utilization efficiency in wheat.

Effects of LAIR-1 on hepatocellular carcinoma cell proliferation and invasion via PI3K-AKT-mTOR pathway regulation.

INTRODUCTION: Hepatocellular carcinoma (HCC) is one of the common malignant tumors. Although surgical resection is the best treatment for HCC, many patients with HCC are found to have metastases at the time of initial diagnosis and lose the opportunity for radical treatment. Therefore, the study of the invasion and metastasis of HCC has always been the focus of HCC research. This study aimed to assess the influence of LAIR-1 on HCC cell proliferation and invasion and the relevant mechanisms involved in this process. METHODS: Immunocytochemical staining assay, quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting (WB) were used to detect the expression of LAIR-1mRNA and protein in healthy human hepatocyte LO2 and the HCC cell lines HepG2, Bel-7402, MHCC97-H, and Huh-7. Then, we evaluated the cell viability, colony formation, and invasion of MHCC97-H and Huh-7 cells in each group by silencing or overexpressing LAIR-1 expression in MHCC97-H and Huh-7 cells, respectively. WB was used to detect the expression levels of PI3K-AKT-mTOR pathway related proteins. RESULTS: Our findings showed that LAIR-1 can inhibit cell viability, colony formation and invasion in vitro. Meanwhile, LAIR-1 significantly downregulated the expression of PI3K, p-AKT and p-mTOR, which were abolished by the PI3K inhibitor, LY294002. CONCLUSIONS: Our study revealed that LAIR-1 inhibited cell proliferation and invasion, probably via suppressing the PI3K-AKT-mTOR pathway.

Protective Effect of Retrograde Reperfusion Against Hepatic Autophagy Impairment in Rat Liver Transplantation.

The retrograde reperfusion (RTR) technique was introduced in orthotopic liver transplantation (OLT) to improve initial postoperative liver function, but the related mechanisms remain unexplained. We investigated the influences of different reperfusion sequences, including initial portal reperfusion (IPR) and RTR, on hepatic ischemia/reperfusion (I/R) injury and autophagic activity in a simplified rat orthotopic liver transplantation (ROLT) model. METHODS: First, we established an ROLT model of male Sprague-Dawley rats to simulate either the IPR or RTR technique. The operative times and survival rates until postoperative day (POD) 7 were recorded. Liver enzyme levels, histologic damage, and in situ apoptosis were assessed. Second, we evaluated differences in the autophagic flux of liver grafts at 1, 2, and 6 hours after reperfusion between the IPR and RTR techniques. All experimental procedures involving animals were approved by the Institutional Animal Ethics Committee of the 900th Hospital of PLA. RESULTS: In the first experiment, all animals survived to POD 7. In contrast to the IPR sequence, the RTR technique decreased the extent of graft I/R injury. In the second experiment, reperfusion markedly impaired the autophagic flux of ischemic liver grafts, but the RTR technique could alleviate and postpone the reduction in autophagy after I/R. CONCLUSIONS: A feasible modified ROLT model with the cuff method was described and could flexibly simulate 2 reperfusion techniques: IPR and RTR. The use of the RTR sequence exhibited a protective effect against I/R injury and impairment of autophagy in liver grafts.