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Background: Plant U-box (PUB) E3 ubiquitin ligases play essential roles in many biological processes and stress responses, but little is known about their functions in sorghum (Sorghum bicolor L.). Results: In the present study, 59 SbPUBgenes were identified in the sorghum genome. Based on the phylogenetic analysis, the 59 SbPUB genes were clustered into five groups, which were also supported by the conserved motifs and structures of these genes. SbPUBgenes were found to be unevenly distributed on the 10 chromosomes of sorghum. Most PUB genes (16) were found on chromosome 4, but there were no PUBgenes on chromosome 5. Analysis of cis-acting elements showed that SbPUBgenes were involved in many important biological processes, particularly in response to salt stress. From proteomic and transcriptomic data, we found that several SbPUB genes had diverse expression under different salt treatments. To verify the expression of SbPUBs, qRT-PCR analyses also were conducted under salt stress, and the result were consistent with the expression analysis. Furthermore, 12 SbPUB genes were found to contain MYB-related elements, which are important regulators of flavonoid biosynthesis. These results, which were consistent with our previous multi-omics analysis of sorghum salt stress, laid a solid foundation for further mechanistic study of salt tolerance in sorghum. Our study showed that PUB genes play a crucial role in regulating salt stress, and might serve as promising targets for breeding of salt-tolerant sorghum in the future.

Background Sorghum is an important food staple in the developing world, with the capacity to grow under severe conditions such as salinity, drought, and a limited nutrient supply. As a serious environmental stress, soil salinization can change the composition of rhizosphere soil bacterial communities and induce a series of harm to crops. And the change of rhizospheric microbes play an important role in the response of plants to salt stress. However, the effect of salt stress on the root bacteria of sorghum and interactions between bacteria and sorghum remains poorly understood. Results The purpose of this study was to assess the effect of salt stress on sorghum growth performance and rhizosphere bacterial community structure. Statistical analysis confirmed that low high concentration stress depressed sorghum growth. Further taxonomic analysis revealed that the bacterial community predominantly consisted of phyla Proteobacteria, Actinobacteria, Acidobacteria, Chloroflexi, Bacteroidetes and Firmicutes in sorghum rhizosphere soil. Low salt stress suppressed the development of bacterial diversity less than high salt stress in both bulk soil and planted sorghum soil. Different sorghum development stages in soils with different salt concentrations enriched distinctly different members of the root bacteria. No obviously different effect on bacterial diversity were tested by PERMANOVA analysis between different varieties, but interactions between salt and growth and between salt and variety were detected. The roots of sorghum exuded phenolic compounds that differed among the different varieties and had a significant relationship with rhizospheric bacterial diversity. These results demonstrated that salt and sorghum planting play important roles in restructuring the bacteria in rhizospheric soil. Salinity and sorghum variety interacted to affect bacterial diversity. Conclusions In this paper, we found that salt variability and planting are key factors in shifting bacterial diversity and community. In comparison to bulk soils, soils under planting sorghum with different salt stress levels had a characteristic bacterial environment. Salinity and sorghum variety interacted to affect bacterial diversity. Different sorghum variety with different salt tolerance levels had different responses to salt stress by regulating root exudation. Soil bacterial community responses to salinity and exotic plants could potentially impact the microenvironment to help plants overcome external stressors and promote sorghum growth. While this study observed bacterial responses to combined effects of salt and sorghum development, future studies are needed to understand the interaction among bacteria communities, salinity, and sorghum growth.

In recent years, mobile operating systems, represented by android and iOS, have become more and more popular in smartphones. However, the energy issue in smartphones, which refers to the poor battery capacity and management schemes, has been the bottle-neck to further advance the development in this area. Generally, mobile applications have to consider both performance and energy consumption. But unfortunately, few works have been focused on this issue. In this paper, we aim at conducting an experimental study on the performance and energy tradeoffs for mobile applications. In particular, we focus on mobile database applications as they are one of the basic applications on mobile operating systems. In detail, we use the android system as the basic mobile platform, and the TPC-H benchmark as the workload, and build a benchmark platform called TPCdroid to conduct performance and energy measurement. In TPCdroid, we control the mobile database performance by changing the processor frequency. The initial experimental results show that lowering frequency is not always helpful for reducing energy consumption. Moreover, we found that the traditional energy reducing technologies based on X86 and magnetic disks are not suitable for mobile database applications running on ARM and flash memory. Finally, we analyse the relationship between performance and energy consumption under different kinds of workloads, which is done by adjusting the parameters reflecting performance and energy consumption for mobile database applications. The results show that the energy consumption has a dynamic connection with the performance in mobile database applications.