A Locus Controlling Leaf Rolling Degree in Wheat under Drought Stress Identified by Bulked Segregant Analysis.

Drought stress frequently occurs, which seriously restricts the production of wheat (Triticum aestivum L.). Leaf rolling is a typical physiological phenomenon of plants during drought stress. To understand the genetic mechanism of wheat leaf rolling, we constructed an F2 segregating population by crossing the slight-rolling wheat cultivar "Aikang 58" (AK58) with the serious-rolling wheat cultivar ″Zhongmai 36″ (ZM36). A combination of bulked segregant analysis (BSA) with Wheat 660K SNP Array was used to identify molecular markers linked to leaf rolling degree. A major locus for leaf rolling degree under drought stress was detected on chromosome 7A. We named this locus LEAF ROLLING DEGREE 1 (LERD1), which was ultimately mapped to a region between 717.82 and 720.18 Mb. Twenty-one genes were predicted in this region, among which the basic helix-loop-helix (bHLH) transcription factor TraesCS7A01G543300 was considered to be the most likely candidate gene for LERD1. The TraesCS7A01G543300 is highly homologous to the Arabidopsis ICE1 family proteins ICE/SCREAM, SCREAM2 and bHLH093, which control stomatal initiation and development. Two nucleotide variation sites were detected in the promoter region of TraesCS7A01G543300 between the two wheat cultivars. Gene expression assays indicated that TraesCS7A01G543300 was higher expressed in AK58 seedlings than that of ZM36. This research discovered a candidate gene related to wheat leaf rolling under drought stress, which may be helpful for understanding the leaf rolling mechanism and molecular breeding in wheat.

Functional Characterization of Soybean Diacylglycerol Acyltransferase 3 in Yeast and Soybean.

Diacylglycerol acyltransferases (DGAT) function as the key rate-limiting enzymes in de novo biosynthesis of triacylglycerol (TAG) by transferring an acyl group from acyl-CoA to sn-3 of diacylglycerol (DAG) to form TAG. Here, two members of the type 3 DGAT gene family, GmDGAT3-1 and GmDGAT3-2, were identified from the soybean (Glycine max) genome. Both of them were predicted to encode soluble cytosolic proteins containing the typical thioredoxin-like ferredoxin domain. Quantitative PCR analysis revealed that GmDGAT3-2 expression was much higher than GmDGAT3-1's in various soybean tissues such as leaves, flowers, and seeds. Functional complementation assay using TAG-deficient yeast (Saccharomyces cerevisiae) mutant H1246 demonstrated that GmDGAT3-2 fully restored TAG biosynthesis in the yeast and preferentially incorporated monounsaturated fatty acids (MUFAs), especially oleic acid (C18:1) into TAGs. This substrate specificity was further verified by fatty-acid feeding assays and in vitro enzyme activity characterization. Notably, transgenic tobacco (Nicotiana benthamiana) data showed that heterogeneous expression of GmDGAT3-2 resulted in a significant increase in seed oil and C18:1 levels but little change in contents of protein and starch compared to the EV-transformed tobacco plants. Taken together, GmDGAT3-2 displayed a strong enzymatic activity to catalyze TAG assembly with high substrate specificity for MUFAs, particularly C18:1, playing an important role in the cytosolic pathway of TAG synthesis in soybean. The present findings provide a scientific reference for improving oil yield and FA composition in soybean through gene modification, further expanding our knowledge of TAG biosynthesis and its regulatory mechanism in oilseeds.

Association Analysis Revealed That TaPYL4 Genes Are Linked to Plant Growth Related Traits in Multiple Environment.

Abscisic acid (ABA), one of phytohormones, plays an important regulatory role in plant growth and development. ABA receptor PYL4 (pyrabactin resistance 1-like 4) was previously detected to be involved in plant response to a variety of stresses. TaPYL4 overexpression could enhance wheat (Triticum aestivum) drought resistance. In order to further investigate TaPYL4's role in regulating development of other major agronomic traits in wheat, genes of TaPYL4-2A, TaPYL4-2B, and TaPYL4-2D were cloned from wheat, respectively. Polymorphism analysis on TaPYL4 sequences revealed that encoding regions of the three genes were highly conserved, without any SNP (single nucleotide polymorphism) presence. However, nine SNPs and four SNPs were identified in the promoter regions of TaPYL4-2A and TaPYL4-2B, respectively. Functional molecular markers were developed based on these polymorphisms, which were then used to scan a natural population of 323 common wheat accessions for correlation analysis between genotype and the target phenotypic traits. Both TaPYL4-2A and TaPYL4-2B markers were significantly correlated with plant growth-related traits under multiple environments (well-watered, drought and heat stress treatments). The additive effects of TaPYL4-2A and TaPYL4-2B were verified by the combinational haplotype (Hap-AB1∼Hap-AB4) effects determined from field data. Cis-acting elements were analyzed in the promoters of TaPYL4-2A and TaPYL4-2B, showing that a TGA-element bound by ARFs (auxin response factors) existed only in Hap-2A-1 of TaPYL4-2A. Gene expression assays indicated that TaPYL4-2A was constitutively expressed in various tissues, with higher expression in Hap-2A-1 genotypes than in Hap-2A-2 materials. Notably, TaARF4 could act as TaPYL4-2A transcription activator in Hap-2A-1 materials, but not in Hap-2A-2 genotypes. Analysis of geographic distribution and temporal frequency of haplotypes indicated that Hap-AB1 was positively selected in wheat breeding in China. Therefore, TaPYL4-2A and TaPYL4-2B could be a valuable target gene in wheat genetic improvement to develop the ideal plant architecture.

External Modulation Optical Coherent Domain Reflectometry with Long Measurement Range.

Optical coherent domain reflectometry (OCDR) can achieve a high spatial resolution that is independent of the bandwidth of the receiver, but the measurement range is usually very limited. Here we propose an external modulation OCDR system, in which a pair of linear frequency-modulated pulses generated by one modulator are employed as the probe pulse and the reference, respectively. The spatial resolution is determined by the frequency modulation range of the pulse, and the measurement speed is boosted by orders because the proposed technology can simultaneously diagnose a section of fiber with each pair of pulses, while only a single point can be accessed at a time in typical OCDR. In the demonstrational experiment, a measurement range of up to 50 km is achieved with a spatial resolution of 1.4 m and a measuring time of less than 30 s.

A transposon in the vacuolar sorting receptor gene TaVSR1-B promoter region is associated with wheat root depth at booting stage.

Root depth, as an important component of root architecture, plays a significant role in growth, grain yield determination and abiotic stress tolerance in crop plants, but its genetic basis remains poorly elucidated. In this study, a panel composed of 323 wheat (Triticum aestivum L.) accessions was assessed for variation in root depth and genotyped with the Wheat 660K SNP Array. GWAS (genome-wide association study) detected significant association between a 125 bp miniature inverted-repeat transposable element (MITE) in the promoter of the TaVSR1-B gene with root depth at the booting stage. We showed that the MITE repressed TaVSR1-B expression by DNA methylation and H3K27 tri-methylation. The roles of TaVSR1-B in root growth were verified by altered expression of the gene in transgenic wheat, rice and a tavsr1 TILLING mutant. Increased TaVSR1-B expression made the root elongation zone shorter and the differentiation zone longer, leading to deeper root. This work provides novel insight into the genetic basis of variation in root depth and a promising target for genetic improvement of root architecture in wheat.

Impact of intraoperative allogenic and autologous transfusion on immune function and prognosis in patients with hepatocellular carcinoma.

The effect of intraoperative blood transfusion on the immune function and prognosis of hepatocellular carcinoma (HCC) has not been fully investigated. The aim of this study was to evaluate the effects of intraoperative autologous blood transfusion and allogeneic blood transfusion on immune function and prognosis in surgically treated HCC patients. One hundred fourteen primary hepatic carcinoma patients who would undergo selective operations were divided into two groups, 35 patients in the experimental group received intraoperative autologous blood transfusion and 79 patients in the control group received allogeneic blood transfusion. The amount of serum T lymphocyte subsets, natural killer (NK) cells and immunoglobulin before and after operation, as well as the recurrence-free survival (RFS) were compared. Results shown that, there was no significant difference in the level of immunocytes and immunoglobulin between the two groups before treatment (P > .05). At 1 day after surgery, there were significant differences in T lymphocyte, NK cells and immunoglobulin levels before and after transfusion. CD3+, CD4+, CD4+/CD8+, and NK cells in autologous transfusion group were significantly higher than those in allogeneic transfusion group (P < .05); the level of IgG, IgM, and IgA in allogeneic transfusion group were significantly lower than those before operation (P < .05), the level of IgG, IgM, and IgA in autologous transfusion group did not significantly fluctuate, and significantly higher than those of allogeneic transfusion group (P < .05). At 5 days after surgery, all indexes of autologous transfusion group recovered to the preoperative level, the levels of CD3+, CD4+, CD4+/CD8+, NK cells, IgG, IgM, and IgA were significantly higher than those of allogeneic transfusion group (P < .05). The follow-up results showed that the RFS of autologous transfusion group was significantly higher than that of allogeneic transfusion group (P < .05). In conclusion, compared with allogeneic blood transfusion, intraoperative autologous blood transfusion possessed less impact on immune function, it may even improve immune function and RFS in HCC patients after surgery. Therefore, HCC patients should be recommended to receive autologous blood transfusion instead of allogeneic blood transfusion when they need blood transfusion during the perioperative period.

Controlling quantum interference in phase space with amplitude.

We experimentally show a quantum interference in phase space by interrogating photon number probabilities (n = 2, 3, and 4) of a displaced squeezed state, which is generated by an optical parametric amplifier and whose displacement is controlled by amplitude of injected coherent light. It is found that the probabilities exhibit oscillations of interference effect depending upon the amplitude of the controlling light field. This phenomenon is attributed to quantum interference in phase space and indicates the capability of controlling quantum interference using amplitude. This remarkably contrasts with the oscillations of interference effects being usually controlled by relative phase in classical optics.

Hong-Ou-Mandel dip measurements of polarization-entangled photon pairs at 1550 nm.

We performed a quantum interference experiment using two polarization-entangled photon pairs at 1550 nm, created in periodically poled lithium niobate waveguides. Using four-fold coincidences, a Hong-Ou-Mandel dip at diagonal polarization was observed with a visibility of 74.5% before subtracting accidental coincidences. This experiment lays a foundation for demonstrating polarization-based entanglement swapping and for realizing a quantum relay.

Low-threshold diode-pumped Yb3+,Na+:CaF2 self-Q-switched laser.

For the first time to our knowledge, the laser performance of Yb3+, Na+-codoped CaF2 single crystals was demonstrated. Self-Q-switched laser operation at 1050nm was observed for 976 nm diode pumping at room temperature. On 5 W of incident power, the repetition rate and width of the self-Q-switched pulses reached 28 kHz and 1.5 micros, respectively. A maximal slope efficiency of 20.3% and minimal threshold absorbed pump power of 30 mW were respectively achieved with different output couplers, showing the promising application of Yb3+, Na+-codoped CaF2 crystals as compact and efficient solid-state lasers.