Exogenous melatonin improves germination rate in buckwheat under high temperature stress by regulating seed physiological and biochemical characteristics.

The germinations of three common buckwheat (Fagopyrum esculentum) varieties and two Tartary buckwheat (Fagopyrum tataricum) varieties seeds are known to be affected by high temperature. However, little is known about the physiological mechanism affecting germination and the effect of melatonin (MT) on buckwheat seed germination under high temperature. This work studied the effects of exogenous MT on buckwheat seed germination under high temperature. MT was sprayed. The parameters, including growth, and physiological factors, were examined. The results showed that exogenous MT significantly increased the germination rate (GR), germination potential (GP), radicle length (RL), and fresh weight (FW) of these buckwheat seeds under high-temperature stress and enhanced the content of osmotic adjustment substances and enzyme activity. Comprehensive analysis revealed that under high-temperature stress during germination, antioxidant enzymes play a predominant role, while osmotic adjustment substances work synergistically to reduce the extent of damage to the membrane structure, serving as the primary key indicators for studying high-temperature resistance. Consequently, our results showed that MT had a positive protective effect on buckwheat seeds exposed to high temperature stress, providing a theoretical basis for improving the ability to adapt to high temperature environments.

A Genomic Analysis of Bacillus megaterium HT517 Reveals the Genetic Basis of Its Abilities to Promote Growth and Control Disease in Greenhouse Tomato.

Bacillus megaterium is well known as a plant growth-promoting rhizobacterium, but the relevant molecular mechanisms remain unclear. This study aimed to elucidate the effects of B. megaterium HT517 on the growth and development of and the control of disease in greenhouse tomato and its mechanism of action. A pot experiment was conducted to determine the effect of B. megaterium on tomato growth, and this experiment included the HT517 group (3.2 × 108 cfu/pot) and the control group (inoculated with the same amount of sterilized suspension). An antagonistic experiment and a plate confrontation experiment were conducted to study the antagonistic effect of B. megaterium and Fusarium oxysporum f.sp. lycopersici. Liquid chromatography-mass spectrometry was used to determine the metabolite composition and metabolic pathway of HT517. PacBio+Illumina HiSeq sequencing was utilized for map sequencing of the samples. An in-depth analysis of the functional genes related to the secretion of these substances by functional bacteria was conducted. HT517 could secrete organic acids that solubilize phosphorus, promote root growth, secrete auxin, which that promotes early flowering and fruiting, and alkaloids, which control disease, and reduce the incidence of crown rot by 51.0%. The complete genome sequence indicated that the strain comprised one circular chromosome with a length of 5,510,339 bp (including four plasmids in the genome), and the GC content accounted for 37.95%. Seven genes (pyk, aceB, pyc, ackA, gltA, buk, and aroK) related to phosphate solubilization, five genes (trpA, trpB, trpS, TDO2, and idi) related to growth promotion, eight genes (hpaB, pheS, pheT, ileS, pepA, iucD, paaG, and kamA) related to disease control, and one gene cluster of synthetic surfactin were identified in this research. The identification of molecular biological mechanisms for extracellular secretion by the HT517 strain clarified that its organic acids solubilized phosphorus, that auxin promoted growth, and that alkaloids controlled tomato diseases.

Threshold effect of government subsidy, corporate social responsibility and brand value using the data of China's top 500 most valuable brands.

An increasing number of firms have begun to attach importance to corporate social responsibility (CSR) to obtain sustainable strategic advantages in the competitive market. On the basis of nonlinear perspective, panel data of A-share listed companies in the ranking list of China's Top 500 Most Valuable Brands in 2012-2018 and Hansen panel threshold regression technology were adopted. With government subsidy and CSR being threshold variables, the internal mechanism about the influence of government subsidy and CSR on brand value was explored. Results show that the following. (1) CSR has a significantly inverted U-type threshold effect on brand value. (2) Government subsidy facilitates CSR with diminishing marginal utility. (3) When a difference exists in the strength of government subsidy, the influence of CSR on brand value presents a significant N-type law. Furthermore, threshold regression method was used to innovatively explore the complex nonlinear relationship among government subsidy, CSR, and brand value. This relationship has a significantly practical significance for listed firms for weighing the business decisions regarding the input of CSR and brand value, as well as subsidy policies for enterprises by the government.

Major QTL for Seven Yield-Related Traits in Common Wheat (Triticum aestivum L.).

Flag leaves, plant height (PH), and spike-related traits are key determinants contributing to yield potential in wheat. In this study, we developed a recombinant inbred line (RIL) population with 94 lines derived from the cross between 'AS985472' and 'Sumai 3.' A genetic map spanned 3553.69 cM in length were constructed using 1978 DArT markers. Severn traits including flag leaf width (FLW), flag leaf length (FLL), PH, anthesis date (AD), spike length (SL), spikelet number spike (SNS), and spike density (SD) were evaluated against this RIL population under three different environments. Combined phenotypic data and genetic map, we identified quantitative trait loci (QTL) for each trait. A total of four major and stably expressed QTLs for FLW, PH, and SD were detected on chromosomes 2D and 4B. Of them, the major QTLs individually explained 10.10 - 30.68% of the phenotypic variation. QTLs with pleiotropic effects were identified on chromosomes 4A and 6D as well. Furthermore, the genetic relationships between seven yield-related traits were detected and discussed. A few genes related to leaf growth and development at the interval of a major locus for FLW on chromosome 2D were predicated. Overall, the present study provided useful information for understanding the genetic basis of yield-related traits and will be useful for marker-assisted selection in wheat breeding.

Identification of a novel genomic region associated with resistance to Fusarium crown rot in wheat.

KEY MESSAGE: Genome-wide association study (GWAS) on 358 Chinese wheat germplasms and validation in a biparental population identified a novel significant genomic region on 5DL for FCR resistance. Fusarium crown rot (FCR) is a chronic and severe disease in many dryland wheat-producing areas worldwide. In the last few years, the incidence and severity of FCR progressively increased in China, and the disease has currently become a new threat to local wheat crops. Here, we report a genome-wide association study (GWAS) on a set of 358 Chinese germplasms with the wheat 55 K SNP array. A total of 104 SNPs on chromosomes 1BS, 1DS, 2AL, 5AL, 5DS, 5DL, 6BS and 7BL were significantly associated with seedling resistance to FCR in the association panel. Of these SNPs, a novel 13.78 Mb region targeted by five SNPs on chromosome arm 5DL was continually detected in all three trials. The effects of this region on FCR resistance was confirmed in biparental population. qRT-PCR showed that within this 5DL region, several genes encoding TIR-NBS-LRR proteins and proteins related to mycotoxins deoxynivalenol (DON) detoxification increased rapidly in the disease-resistant variety 04 Zhong 36 than the susceptible variety Xinmai 26 after inoculation. Our study provides new insights into gene discovery and creation of new cultivars with desirable alleles for improving FCR resistance in wheat.

Development of a quartz crystal microbalance biosensor with aptamers as bio-recognition element.

The ultimate goal in any biosensor development project is its use for actual sample detection. Recently, there has been an interest in biosensors with aptamers as bio-recognition elements, but reported examples all deal with standards, not human serum. In order to verify the differences of aptamer-based biosensor and antibody-based biosensor in clinical detection, a comparison of the performance of aptamer-based and antibody-based quartz crystal microbalance (QCM) biosensors for the detection of immunoglobulin E (IgE) in human serum was carried out. Aptamers (or antibodies) specific to IgE were immobilized on the gold surface of a quartz crystal. The frequency shifts of the QCM were measured. The linear range with the antibody (10-240 µg/L) compared to that of the aptamer (2.5-200 µg/L), but a lower detection limit could be observed in the aptamer-based biosensor. The reproducibility of the two biosensors was comparable. The aptamers were equivalent or superior to antibodies in terms of specificity and sensitivity. In addition, the aptamer receptors could tolerate repeated affine layer regeneration after ligand binding and recycling of the biosensor with little loss of sensitivity. When stored for three weeks, the frequency shifts of the aptamer-coated crystals were all greater than 90% of those on the response at the first day.

Aptamer-based piezoelectric quartz crystal microbalance biosensor array for the quantification of IgE.

The aim of this study was to develop a rapid method to measure IgE in human serum by use of a direct aptamer-based biosensor based on a quartz crystal microbalance (QCM). An avidin monolayer was applied to immobilize aptamers specific for IgE on the gold surface of a quartz crystal. The frequency shifts (FS) of the QCM were measured and related to IgE concentrations. We could demonstrate that aptamers were able to detect IgE with high specificity and sensitivity in 15 min. A linear relationship existed between the FS (Hz) and the IgE concentrations from 2.5 to 200 microg/L in buffer and human serum. The regression equation was y = 1.03x - 0.06 for this QCM method and chemiluminescence in 50 clinical human serum samples. In addition, the aptamer receptors tolerated repeated affine layer regeneration after ligand binding and recycling of the biosensor with little loss of sensitivity. When stored for 3 weeks, the FS were all greater than 90% of those on the response at the first day. The QCM biosensor can measure IgE and offer advantages of high specificity, reusability, low detection limit, no label or sample pretreatment, and low sample requirement. The aptamer QCM biosensor was suitable for sensitive and specific protein detection, representing an innovative tool for future proteomics.