Genome-Wide DNA Polymorphism Analysis and Molecular Marker Development for the Setaria italica Variety “SSR41” and Positional Cloning of the Setaria White Leaf Sheath Gene SiWLS1

Genome-wide DNA polymorphism analysis and molecular marker development are important for forward genetics research and DNA marker-assisted breeding. As an ideal model system for Panicoideae grasses and an important minor crop in East Asia, foxtail millet (Setaria italica) has a high-quality reference genome as well as large mutant libraries based on the “Yugu1” variety. However, there is still a lack of genetic and mutation mapping tools available for forward genetics research on S. italica. Here, we screened another S. italica genotype, “SSR41”, which is morphologically similar to, and readily cross-pollinates with, “Yugu1”. High-throughput resequencing of “SSR41” identified 1,102,064 reliable single nucleotide polymorphisms (SNPs) and 196,782 insertions/deletions (InDels) between the two genotypes, indicating that these two genotypes have high genetic diversity. Of the 8,361 high-quality InDels longer than 20 bp that were developed as molecular markers, 180 were validated with 91.5% accuracy. We used “SSR41” and these developed molecular markers to map the white leaf sheath gene SiWLS1. Further analyses showed that SiWLS1 encodes a chloroplastlocalized protein that is involved in the regulation of chloroplast development in bundle sheath cells in the leaf sheath in S. italica and is related to sensitivity to heavy metals. Our study provides the methodology and an important resource for forward genetics research on Setaria

Screening of Mutants Related to the C4 Photosynthetic Kranz Structure in Foxtail Millet

C4 plants exhibit significantly higher photosynthetic, water and nutrient use efficiency compared with C3 plants. Kranz anatomy is associated with many C4 plants in which bundle sheath cells surround the veins and are themselves surrounded by mesophyll cells. This specialized Kranz anatomy is elucidated as an important contributor to C4 photosynthetic activities in C4 plant. Characterizing the molecular basis of Kranz structure formation has become a key objective for studies of C4 photosynthesis. However, severe mutants that specifically disrupt Kranz anatomy have not been identified. In this study, we detected 549 stable ethyl methane sulfonate-induced foxtail millet (cultivar Yugu1) mutants related to leaf development and photosynthesis among 2,709 mutants screened (M3/M4 generation). The identified mutants included 52 that had abnormal leaf veins (with abnormal starch accumulation based on iodine staining). Each of the 52 mutants was characterized through an analysis of leaf morphology, and through microscopic observations of leaf tissue sections embedded in resin and paraffin. In total, 14 mutants were identified with abnormal Kranz structures exemplified by small bundle sheath cell size. Additional phenotypes of the mutants included poorly differentiated mesophyll and bundle sheath cells, increased vein density and the absence of chloroplasts in the bundle sheath cells. Kranz structure mutations were accompanied by varying leaf thickness, implying these mutations induced complex effects. We identified mutations related to Kranz structure development in this trial, which may be useful for the mapping and cloning of genes responsible for mediating Kranz structure development

Satellite confirmation of the dominance of chlorofluorocarbons in the global stratospheric chlorine budget

OBSERVED increases in concentrations of chlorine in the stratosphere1-7 have been widely implicated in the depletion of lower-stratospheric ozone over the past two decades8-14. The present concentration of stratospheric chlorine is more than five times that expected from known natural 'background' emissions from the oceans and biomass burning15-18, and the balance has been estimated to be dominantly anthropogenic in origin, primarily due to the breakdown products of chlorofluorocarbons (CFCs)19,20. But despite the wealth of scientific data linking chlorofluorocarbon emissions to the observed chlorine increases, the political sensitivity of the ozone-depletion issue has generated a re-examination of the evidence21,22. Here we report a four-year global time series of satellite observations of hydrogen chloride (HCl) and hydrogen fluoride (HF) in the stratosphere, which shows conclusively that chlorofluorocarbon releases - rather than other anthropogenic or natural emissions - are responsible for the recent global increases in stratospheric chlorine concentrations. Moreover, all but a few per cent of observed stratospheric chlorine amounts can be accounted for by known natural and anthropogenic tropospheric emissions. Altogether, these results implicate the chlorofluorocarbon s beyond reasonable doubt as dominating ozone depletion in the lower stratosphere

A new instrument for the study of mesospheric gravity waves through nightglow observations.

The observations of the mesospheric nightglow have been used to study the characteristics of propagating gravity waves for two decades. This study involves the design and construction of an optical instrument with high spatial and temporal resolutions and the development of proper observation mode and data analysis techniques. A new variety of low resolution spectrometer is developed in this dissertation. This device, an Image Plane Detector Spectrophotometer (IPDS), measures the rotational temperature and brightness of molecular band emissions or the brightness of an atomic line. It uses an interference filter as a dispersive element and an Image Plane Detector (IPD) as the photon collecting device. The IPDS can measure a spectrum at twelve wavelength positions simultaneously without mechanical scan. Therefore, it has the advantage of increasing temporal resolution in nightglow observations. The IPDS has high throughput compared to traditional spectroscopic instrument, and it is compact in size and portable. This dissertation describes the principle, design, construction and calibrations of a ground-based IPDS. Although the commercial filter used did not fully meet our specifications, the instrument performed reasonably well. The data reduction technique is described. This technique is used to recover the rotational temperature and brightness of molecular band emissions from observed spectral signals. The errors in recovered parameters are also examined. The ground-based IPDS was set up to measure night-time mesosopheric emissions in Ann Arbor, Michigan. The rotational temperature and brightness of the O\sb2(0-1) and OH(6-2) bands were obtained as a function of local time at one position in the sky. Oscillations in the temperature and brightness are clearly revealed, indicating the presence of gravity waves. Some degrees of co-variances showed in the brightness and temperature trends. A four-position observation mode of measuring (OI) green line intensity is described. This measurement is conducted in order to examine the possibility of determining gravity wave parameters. A discussion is given about obtaining wave propagation direction and horizontal wavelength using time delays among the observed intensities at four positions. The result shows that by using only time delays, one cannot uniquely identify the wave. A criterion of eliminating some of possible waves is presented, which is based upon the wave-airglow interaction theory. The effect of background wind is also discussed. As a conclusion, a multi-instrument observation is suggested to completely study the characteristics of gravity waves in the mesosphere.Ph.D.Atmospheric and Space SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/105569/1/9135642.pdfDescription of 9135642.pdf : Restricted to UM users only

Stabilized Brillouin laser with sub-Hz fundamental linewidth aided by frequency shifted optical injection locking

Stable laser emission with ultra-narrow linewidth plays an important role in making fundamental scientific breakthroughs. Here, we propose and demonstrate a new technique for the generation of an ultra-narrow linewidth and highly stable laser based on stimulated Brillouin scattering in combination with a frequency-shifted optical injection locking mechanism. The laser performance is characterized via a delayed self-heterodyne interference system, where the white frequency noise floor is ∼20 mHz2/Hz, corresponding to a fundamental linewidth of about 63 mHz. The maximum deviation in the output power is less than 1.5% over more than 10 min. The operation of the laser can be stabilized without the need for active optoelectronic feedback. The scheme presented in this work enables narrow linewidth and stable single-frequency fiber lasers in a robust and efficient way, which has shown promising potential for many applications

New-Generation Quality and Safety Management of the Construction Industry

Construction is a complex human–machine–environment system, and the quality and safety management during construction faces numerous challenges. As the new-generation information technology develops, digital twin now can be used in construction to improve the quality and safety management and promote smart construction in China. Computability and controllability of the whole construction process is expected to be achieved using the digital twin technology; digital management of construction sites can be realized using advanced sensing, computing, and other technologies. In this article, we first investigate the demand for the application of digital twin into the construction quality management and analyze the research status and problems of the application. Subsequently, we propose a next-generation construction quality and safety management system that is composed of product intelligent design for construction quality and safety control, intelligent sensing and analysis of construction quality and safety status, data-driven construction quality and safety control, and construction quality management and dynamic supervision. Furthermore, we propose suggestions for the application of digital twin technology in the construction industry in China from the aspects of management, technology, as well as standards and specifications

Data from: SiSTL1 encoding a large subunit of RNR, is crucial for plant growth, chloroplast biogenesis, and cell cycle progression in Setaria italica

The activity of ribonucleotide reductase (RNR), which catalyzes the transformation of four ribonucleoside diphosphates (NDPs) to their corresponding deoxyribonucleoside diphosphates (dNDPs), is the main determiner of the cellular concentration of dNTP pools and should be tightly coordinated with DNA synthesis and cell-cycle progression. Either constitutively increased or decreased RNR activity are indeed likely to interfere with DNA replication and lead to arrested cell cycle progression; however, the mechanisms underlying these disruptive effects in higher plants remain to be uncovered. In this study, we identified a RNR large subunit mutant, sistl1, in Setaria italica (foxtail millet), that exhibited growth retardation as well as striped leaf phenotype, i.e., irregularly reduced leaf vein distances and decreased chloroplast biogenesis. We determined that a Gly737 to Glu substitution occurrring in the C-terminus of the SiSTL1 protein slightly affected its optimal function, leading in turn to the reduced expression of genes variously involved in the assembly and activation of the DNA pre-replicative complex, elongation of replication forks and S phase entry. Our study provides new insight into how SiSTL1 regulates plant growth, chloroplast biogenesis, and cell cycle progression in Poaceae crops