Background Anaerobic germination tolerance is an important trait for direct-seeded rice varieties. Understanding the genetic basis of anaerobic germination is a key for breeding direct-seeded rice varieties. Results In this study, a recombinant inbred line (RIL) population derived from a cross between YZX and 02428 exhibited obvious coleoptile phenotypic differences. Mapping analysis using a high-density bin map indicated that a total of 25 loci were detected across two cropping seasons, including 10 previously detected loci and a total of 13 stable loci. Analysis of the 13 stable loci demonstrated that the more elite alleles that were pyramided in an individual, the higher the values of these traits were in the two cropping seasons. Furthermore, some anaerobic germination-tolerant recombinant inbred lines, namely G9, G10, G16, and G151, were identified. A total of 84 differentially expressed genes were obtained from the 13 stable loci via genome-wide expression analysis of the two parents at three key periods. Among them, Os06g0110200, Os07g0638300, Os07g0638400, Os09g0532900, Os09g0531701 and Os12g0539751 constitute the best candidates associated with anaerobic germination. Conclusions Both the anaerobic germination-tolerant recombinant inbred lines and the loci identified in this study will provide new genetic resources for improving the anaerobic germination tolerance of rice using molecular breeding strategies, as well as will broaden our understanding of the genetic control of germination tolerance under anaerobic conditions. Electronic supplementary material The online version of this article (10.1186/s12864-019-5741-y) contains supplementary material, which is available to authorized users.

No abstract

The microstructure and corrosion behavior of pure magnesium, with 25 ppm Fe but a high corrosion rate, have been studied in this work. It was found that Fe-rich particles, containing also Si, distribute non-uniformly in the Mg matrix and they are spaced at a distance of 100-1000 μm. Before the initiation of localized corrosion, Fe-rich particles play a key role in determining the overall corrosion behavior by supporting hydrogen evolution. During corrosion propagation, Fe-rich particles could be oxidized once they were detached from the Mg matrix and, consequently, lose their cathodic activation. Once the corrosion has taken place over majority of the surface, the effects of crystallographic orientation of the underlying metal dominate the last stage of corrosion, which propagates parallel to the (0001) Magnesium alloys are of great value for industrial applications due to their low density and high strength-to-weight ratio. However, a major deficiency is their comparatively poor corrosion resistance when exposed to aqueous and humid environments.1,2 Consequently, there is a demand to develop magnesium alloys with improved corrosion resistance. 2,3The equilibrium potential for magnesium oxidation is well below the equilibrium potential for hydrogen evolution over the entire pH range of practical interest. As a consequence, the cathodic reaction of hydrogen evolution largely dominates over oxygen reduction during corrosion in an aqueous environment. For this reason, the presence of elements with low overpotentials (or high exchange current density) for hydrogen evolution is likely to produce detrimental effects on the corrosion resistance due to increase in the hydrogen evolution rate. Hanawalt et al. 4 found that four elements (Fe, Ni, Cu, and Co) had a very profound effect on accelerating the corrosion rate of Mg in chloride-containing aqueous environments even at concentrations below 0.2 wt%. Subsequent studies have confirmed that the most critical factor affecting the corrosion behavior of Mg is the presence of impurities.3

Increasing evidences indicate that gut microbiota composition is associated with multiple inflammatory diseases. However, little is known about how gut microbiota changes with age and correlations with gut inflammation at sexual maturity stage of healthy individuals. Elucidating the dynamic changes of gut microbiota in healthy individuals at the sexual maturity stage and correlations with gut inflammation can provide clues for early risk assessment of gut diseases at the sexual maturity stage. Here, the shift in gut bacteria and its relationship with gut inflammation at the sexual maturity stage were explored. Sprague–Dawley rats at the sexual maturity stage were used in this study. 16S rRNA gene sequencing was performed to decipher gut bacteria shifts from the 7th week to the 9th week, and enzyme-linked immunosorbent assay (ELISA) was used to measure gut inflammation and gut barrier permeability. We found an increase in bacterial richness with age and a decrease in bacterial diversity with age. The gut bacteria were primarily dominated by the phyla Firmicutes and Bacteroides and the genus Prevotella. The relative abundance of Firmicutes increased with age, and the relative abundance of Bacteroides decreased with age. There was a positive correlation between body weight and the Firmicutes:Bacteroides ratio. More and more gut microbiota participated in the host gut inflammation and barrier permeability regulation with age. Ruminococcus was the only gut bacteria participated in gut inflammation and barrier permeability regulation both in the 7th week and the 15th week. These results provide a better understanding of the relationship between gut bacteria and gut inflammation in sexually mature rats and show that Ruminococcus may be a potential indicator for early risk assessment of gut inflammation.

No abstract