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Key message: A novel QTL (qSCN-PL10) for SCN resistance and related candidate genes were identified in the soybean variety Pingliang xiaoheidou, and plant basal immunity seems to contribute to the SCN resistance. Soybean cyst nematode (SCN, Heterodera glycines Ichinohe) is one of the most devastating soybean pests worldwide. The development of host plant resistance represents an effective strategy to control SCN. However, owing to the lack of diversity of resistance genes in soybean varieties, further investigation is necessary to identify new SCN resistance genes. By analyzing the resistance phenotypes of soybean variety Pingliang xiaoheidou (Pingliang, ZDD 11047), we found that it exhibited the different resistance phenotypes from PI 88788 and Peking varieties. Because Pingliang variety contains the Rhg1-a (low copy) haplotype and lacks the resistant Rhg4 haplotype, novel quantitative trait locus might account for their SCN resistance. After sequencing parental lines (Magellan and Pingliang) and 200 F2:3 progenies, a high-density genetic map was constructed using the specific length amplified fragment sequencing method and qSCN-PL10 was identified as a novel locus for SCN resistance. Candidate genes were predicted by RNA sequencing (RNA-seq) in the qSCN-PL10 locus region. The RNA-seq analysis performed also indicated that plant basal immunity plays an important role in the resistance of Pingliang to SCN. These results lay a foundation for the use of marker-assisted breeding to enhance the resistance to SCN. [ABSTRACT FROM AUTHOR]

Abstract: This study presents a method for direct measurement of wall surface temperature realising two-dimensional, thermographic phosphorescence imaging. The experiments were performed in a constant-volume combustion chamber (CVCC) wherein the ambient gas and fuel injection conditions closely mimic those found in a typical diesel engine. The new method successfully made use of a high-power light emitting diode (LED) system and intensified charge-coupled device (ICCD) camera—which offers practical advantages such as much lower cost and reduced safety concerns in comparison to laser-based phosphorescence diagnostics. Previous studies have successfully demonstrated measurement strategies using LEDs (Atakan et al., Exp Measur Strat. 10.1088/0957-0233/20/7/075304, 2009; Salem et al., Exp Fluids 49:797-807, 2010); however, most have implemented a lifetime-based approach. Aizawa and Kosaka (Int J Fuels Lubr 1:549-558, 2008) demonstrated the applicability of the absolute intensity method as a viable alternative, using a laser source for excitation. This paper combines Aizawa and Kosaka's intensity-ratio methodology with LED excitation, and implements the technique to a diesel flame/wall interaction case in a pre-burn-type optical CVCC. Europium-doped lanthanum oxysulphide (La2O2S:Eu) was selected as a suitable phosphor material due to its high temperature sensitivity at this engine relevant condition. The present study first investigates how phosphorescence signals are influenced by the coating thickness. The thickness of the phosphor-binder layer was measured by a scanning electron microscope (SEM) in the 11.9-19.0 µm range. The optimal layer thickness was chosen as 14.3 µm, the thinnest possible layer capable of achieving the highest emission signal, as thicker coatings are more prone to thermal gradients—especially at a transient flame/wall interaction condition. Calibration images were obtained in the 294-523 K range with ± 2 K uncertainty in an electric furnace, thereby allowing two-dimensional temperature measurements in the CVCC application. The results obtained for various timings after the start of fuel injection, namely before and after the flame impingement on the wall, indicate effective wall temperature measurements with low spatial (pixel-by-pixel) and shot-to-shot variations of < 7.5 K (95% confidence).Graphical abstract: [ABSTRACT FROM AUTHOR]

Nodule development directly affects nitrogen fixation efficiency during soybean growth. Although abundant genome-based information related to nodule development has been released and some studies have reported the molecular mechanisms that regulate nodule development, information on the way nodule genes operate in nodule development at different developmental stages of soybean is limited. In this report, notably different nodulation phenotypes in soybean roots inoculated with Bradyrhizobium japonicum strain 113-2 at five developmental stages (branching stage, flowering stage, fruiting stage, pod stage and harvest stage) were shown, and the expression of nodule genes at these five stages was assessed quantitatively using RNA-Seq. Ten comparisons were made between these developmental periods, and their differentially expressed genes were analysed. Some important genes were identified, primarily encoding symbiotic nitrogen fixation-related proteins, cysteine proteases, cystatins and cysteine-rich proteins, as well as proteins involving plant-pathogen interactions. There were no significant shifts in the distribution of most GO functional annotation terms and KEGG pathway enrichment terms between these five development stages. A cystatin Glyma18g12240 was firstly identified from our RNA-seq, and was likely to promote nodulation and delay nodule senescence. This study provides molecular material for further investigations into the mechanisms of nitrogen fixation at different soybean developmental stages. [ABSTRACT FROM AUTHOR]