Semi-dwarfing genes have contributed to enhanced lodging resistance, resulting in increased crop productivity. In the history of grain sorghum breeding, the spontaneous mutation, dw1 found in Memphis in 1905, was the first widely used semi-dwarfing gene. Here, we report the identification and characterization of Dw1. We performed quantitative trait locus (QTL) analysis and cloning, and revealed that Dw1 encodes a novel uncharacterized protein. Knockdown or T-DNA insertion lines of orthologous genes in rice and Arabidopsis also showed semi-dwarfism similar to that of a nearly isogenic line (NIL) carrying dw1 (NIL-dw1) of sorghum. A histological analysis of the NIL-dw1 revealed that the longitudinal parenchymal cell lengths of the internode were almost the same between NIL-dw1 and wildtype, while the number of cells per internode was significantly reduced in NIL-dw1. NIL-dw1dw3, carrying both dw1 and dw3 (involved in auxin transport), showed a synergistic phenotype. These observations demonstrate that the dw1 reduced the cell proliferation activity in the internodes, and the synergistic effect of dw1 and dw3 contributes to improved lodging resistance and mechanical harvesting.

Semi-dwarf traits have been widely introgressed into cereal crops to improve lodging resistance. In sorghum (Sorghum bicolor L. Moench), four major unlinked dwarfing genes, Dw1-Dw4, have been introduced to reduce plant height, and among them, Dw3 and Dw1 have been cloned. Dw3 encodes a gene involved in auxin transport, whereas, Dw1 was recently isolated and identified as a gene encoding a protein of unknown function. In this study, we show that DW1 is a novel component of brassinosteroid (BR) signaling. Sorghum possessing the mutated allele of Dw1 (dw1), showed similar phenotypes to rice BR-deficient mutants, such as reduced lamina joint bending, attenuated skotomorphogenesis, and insensitivity against feedback regulation of BR-related genes. Furthermore, DW1 interacted with a negative regulator of BR signaling, BRASSINOSTEROID INSENSITIVE 2 (BIN2), and inhibited its nuclear localization, indicating that DW1 positively regulates BR signaling by inhibiting the function of BIN2. In contrast to rice and wheat breeding which used gibberellin (GA) deficiency to reduce plant height, sorghum breeding modified auxin and BR signaling. This difference may result from GA deficiency in rice and wheat does not cause deleterious side effects on plant morphology, whereas in sorghum it leads to abnormal culm bending.In crop breeding, breeders have significantly changed plant stature during the selection of improved grain crops. One famous example is the introduction of a semi-dwarf trait into rice and wheat in the 1960s. Compared to normal plants, semi-dwarf plants have lower center of gravity, which increases lodging resistance and thus enables plant to sustain high grain yield. This phenomenon was later referred as the 'green revolution' . The mechanism of semi-dwarfism that contributed to the 'green revolution' was the introduction of mutated alleles of gibberellin (GA) 20-oxidase (semidwarf 1; sd1) in rice 1, 2 and DELLA (Rht) in wheat 3 , encoding a GA biosynthesis enzyme and a dominant repressor of GA signal transduction, respectively. Furthermore, it has also been reported that the semi-dwarfism of barley, caused by the introgression of semi-dwarf 1 (sdw1/denso) into cultivars grown in Europe, probably depends on a defect in an ortholog of rice SD1 4-6 . Such wide usage of GA-related mutations to produce semi-dwarf plants has been possible due to a unique feature of GA. That is, GA deficiency specifically causes a decrease in plant height without deleterious side effects on other morphologies or physiologies, whereas dwarfism caused by other mechanisms often induces undesired phenotypes, such as abnormal leaf structure, abnormal internode elongation, and stunted seeds [7][8][9][10] . Therefore, it is rare that mutations involved in mechanisms other than GA deficiency were used to improve lodging resistance in crop breeding. One rare exception is a semi-dwarf barley mutant containing semi-brachytic 1 (uzu), a weak allele of the brassinosteroid (BR) receptor, which is grown in a limited region of East Asia, including areas...

We have developed a new atomic force microscope with differential laser interferometers (DLI-AFM), carried out test measurements of the prototype 1D-grating standards with pitches of 100, 80, 60 and 50 nm using the DLI-AFM and evaluated the uncertainty in the pitch measurements. In the procedures of the pitch calculation, two types of definitions of the peak positions, ‘the centre of gravity method’, and ‘the zero-crossing method’, were compared. The zero-crossing method was adopted in this study since the standard deviation of pitches by the zero-crossing method was smaller than that by the centre of gravity method. The expanded uncertainty (k = 2) was approximately 0.20 nm and was only 0.4% for the nominal pitch of 50 nm. We propose a design of usable 1D-grating standards as certified reference materials.

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An outlier correction procedure for areal surface topography data based on surrounding data for outlier detection and correction is reviewed. The outlier detection is based on the median relative height of the surrounding data within a defined detection window. The threshold value is calculated from a cumulative probability curve of the medians of all data points. The detection window size is selected based on the size of the largest outlier cluster observed on the topography data. The application of the procedure to dental implant surface topography data measured by a confocal laser scanning microscope shows excellent outlier removal compared to typical filtering methods. The procedure only affects outliers, and the information on normal data points remains unchanged. The application to topography data from 21 repeated measurements of a deterministic measuring standard shows great improvement in accuracy and repeatability of surface roughness parameters. The flexibility of the outlier correction procedure is observed through its application to several types of topography data from various types of optical surface measurement systems.