Natural products have long been a crucial source of, or provided inspiration for new agrochemical discovery.  Naturally occurring 18β-glycyrrhetinic acid shows broad-spectrum bioactivities and is a potential skeleton for novel drug discovery.  To extend the utility of 18β-glycyrrhetinic acid for agricultural uses, a series of novel 18β-glycyrrhetinic acid amide derivatives were prepared and evaluated for their antibacterial potency.  Notably, compound 5k showed good antibacterial activity in vitro against Xanthomonas oryzae pv. oryzae (Xoo, EC₅₀=3.64 mg L^–1), and excellent protective activity (54.68%) against Xoo in vivo.  Compound 5k induced excessive production and accumulation of reactive oxygen species in the tested pathogens, resulting in damaging the bacterial cell envelope.  More interestingly, compound 5k could increase the activities of plant defense enzymes including catalase, superoxide dismutase, peroxidase, and phenylalanine ammonia lyase.  Taken together, these enjoyable results suggested that designed compounds derived from 18β-glycyrrhetinic acid showed potential for controlling intractable plant bacterial diseases by disturbing the balance of the phytopathogen’s redox system and activating the plant defense system

Soybean yield has been increased through high planting density, but investigating plant height and petiole traits to select for compact architecture, lodging resistance, and high yield varieties is an underexplored avenue to improve yield.  We compared the relationship between yield-related traits, lodging resistance, and petiole-associated phenotypes in the short petiole germplasm M657 with three control accessions over 2017-2018 in four locations of the Huang-Huai region.  The results showed M657 exhibited stable and high tolerance to high planting density and resistance to lodging, especially at the highest density (8×10⁵ plants ha^-1).  Regression analysis showed that shorter petiole length was significantly associated with increased lodging resistance.  Yield analysis showed that M657 achieved higher yields under higher densities, especially in the north Huang-Huai region.  There are markedly different responses to intra- and inter-row spacing designs among varieties in both lodging and yield related to location and density.  Lodging was positively correlated with planting density, plant height, petiole length, and number of effective branches, and negatively correlated with stem diameter, seed number per plant, and seed weight per plant.  The yield of soybean was increased by appropriately increasing planting density on the basis of current soybean varieties in the Huang-Huai region.  This study provides a valuable new germplasm resource for introgression of compact architecture traits amenable to high yield in high density planting systems and establishes a high-yield model of soybean in the Huang-Huai region.

Tea is one of the most popular non-alcoholic beverages in the world, and free amino acids, especially theanine, make a major contribution to the umami taste of tea.  However, the genetic basis of the variation in amino acid content in tea plants remains largely unknown.  Here, we measured the free amino acid content in fresh leaves of 174 tea accessions over two years using a targeted metabolomics approach and obtained genotype data via RNA sequencing.  Genome-wide association studies were conducted to investigate loci affecting the content of free amino acids.  A total of 69 quantitative trait loci (–log₁₀(P-value)>5) were identified.  Functional annotation revealed that branched-chain amino acid aminotransferase, glutamine synthetase, nitrate transporter, and glutamate decarboxylase might be important for amino acid metabolism.  Two significant loci, glutamine synthetase (Glu1, P=3.71×10^–4; Arg1, P=4.61×10^–5) and branched-chain amino acid aminotransferase (Val1, P=4.67×10^–5; I_Leu1, P=3.56×10^–6), were identified, respectively.  Based on the genotyping result, two alleles of CsGS (CsGS-L and CsGS-H) and CsBCAT (CsBCAT-L and CsBCAT-H) were selected to perform function verification.  Overexpression of CsGS-L and CsGS-H enhanced the contents of glutamate and arginine in transgenic plants, and overexpression of CsBCAT-L and CsBCAT-H promoted the accumulation of valine, isoleucine and leucine.  Enzyme activity assay uncovered that SNP₁₀₅₄ is important for CsGS catalyzing glutamate into glutamine.  Furthermore, CsGS-L and CsGS-H differentially regulated the accumulation of glutamine, and CsBCAT-L and CsBCAT-H differentially regulated the accumulation of branched-chain amino acids.  In summary, the findings in our study would provide new insights into the genetic basis of amino acids contents variation in tea plants and facilitate the identification of elite genes to enhance amino acids content.

Omega-3 (linolenic acid (ALA), docosapentaenoic acid, eicosapentaenoic acid) and omega-6 (linoleic acid (LA), arachidonic acid) polyunsaturated fatty acids are essential for health and normal physiological functioning in humans.  Here we report a genome-wide association study (GWAS) on LA content in chicken meat.  The 19 significant single nucleotide polymorphisms (SNPs) identified by the GWAS approach were annotated in VILL, PLCD1 and OXSR1 genes with highly polymorphic linkage blocks, and explained 4.5% of the phenotypic variation in the LA content.  Specifically, the PLCD1 mRNA expression level was negatively correlated with the LA content, and significantly higher in chickens with low LA content than in those with high LA content.  In addition, PLCD1 was found to be involved in metabolic pathways, etc.  Furthermore, the LA content was correlated with volatile organic compounds (e.g., octanal, etc.), but no relationship was found with intramuscular fat and triglycerides in chicken meat.  The results indicated that there are key SNPs in PLCD1 that regulate the content of LA, and it has no significant effect on fat deposition, but may affect the content of volatile organic compounds (VOCs).

Utilizing the heterosis of indica/japonica hybrid rice (IJHR) is an effective way to further increase rice grain yield.  Rational application of nitrogen (N) fertilizer plays a very important role in using the heterosis of IJHR to achieve its great yield potential.  However, the responses of the grain yield and N utilization of IJHR to N application rates and the underlying physiological mechanism remain elusive.  The purpose of this study was to clarify these issues.  Three rice cultivars currently used in rice production, an IJHR cultivar Yongyou 2640 (YY2640), a japonica cultivar Lianjing 7 (LJ-7) and an indica cultivar Yangdao 6 (YD-6), were grown in the field with six N rates (0, 100, 200, 300, 400, and 500 kg ha^–1) in 2018 and 2019.  The results showed that with the increase in N application rates, the grain yield of each test cultivar increased at first and then decreased, and the highest grain yield was at the N rate of 400 kg ha^–1 for YY2640, with a grain yield of 13.4 t ha^–1, and at 300 kg ha^–1 for LJ-7 and YD-6, with grain yields of 9.4–10.6 t ha^–1.  The grain yield and N use efficiency (NUE) of YY2640 were higher than those of LJ-7 or YD-6 at the same N rate, especially at the higher N rates.  When compared with LJ-7 or YD-6, YY2640 exhibited better physiological traits, including greater root oxidation activity and leaf photosynthetic rate, higher cytokinin content in the roots and leaves, and more remobilization of assimilates from the stem to the grain during grain filling.  The results suggest that IJHR could attain both higher grain yield and higher NUE than inbred rice at either low or high N application rates.  Improved shoot and root traits of the IJHR contribute to its higher grain yield and NUE, and a higher content of cytokinins in the IJHR plants plays a vital role in their responses to N application rates and also benefits other physiological processes. 

Phenotypic screening of soybean germplasm suitable for high planting density is currently the most viable strategy to increase yield.  Previous studies have shown that soybean varieties with dwarf features and a short petiole often exhibit a compact plant architecture which could improve yield through increased planting density, although previously reported short petiole accessions were ultimately not usable for breeding in practice.  Here, we established a method to assess petiole length and identified an elite mutant line, M657, that exhibits high photosynthetic efficiency.  The agronomic traits of M657 were evaluated under field conditions, and appeared to be stable for short petiole across seven locations in northern, Huang–Huai, and southern China from 2017 to 2018.  Compared with the Jihuang 13 wild type, the mutant M657 was shorter in both petiole length and plant height, exhibited lower total area of leaf, seed weight per plant and 100-seed weight, but had an increased number of effective branches and the growth period was prolonged by 2–7 days.  Using M657 as a parental line for crosses with four other elite lines, we obtained four lines with desirable plant architecture and yield traits, thus demonstrating the feasibility of adopting M657 in breeding programs for soybean cultivars of high density and high yield.

High-moisture extrusion technology should be considered one of the best choices for producing plant-based meat substitutes with the rich fibrous structure offered by real animal meat products.  Unfortunately, the extrusion process has been seen as a “black box” with limited information about what occurs inside, causing serious obstacles in developing meat substitutes.  This study designed a high-moisture extrusion process and developed 10 new plant-based meat substitutes comparable to the fibrous structure of real animal meat.  The study used the Feature-Augmented Principal Component Analysis (FA-PCA) method to visualize and understand the whole extrusion process in three ways systematically and accurately.  It established six sets of mathematical models of the high-moisture extrusion process based on 8 000 pieces of data, including five types of parameters.  The FA-PCA method improved the R² values significantly compared with the PCA method.  The Way 3 was the best to predict product quality (Z), demonstrating that the gradually molecular conformational changes (Yⁿ´) were critical in controlling the final quality of the plant-based meat substitutes.  Moreover, the first visualization platform software for the high-moisture extrusion process has been established to clearly show the “black box” by combining the virtual simulation technology.  Through the software, some practice work such as equipment installation, parameter adjustment, equipment disassembly, and data prediction can be easily achieved.

Choriogenesis is the last step of insect oogenesis, a process by which the chorion polypeptides are produced by the follicular cells and deposited on the surface of oocytes in order to provide a highly specialized protective barrier to the embryo.  The essential features of chorion genes have yet to be clearly understood in the diamondback moth, Plutella xylostella, a worldwide Lepidoptera pest attacking cruciferous crops and wild plants.  In this study, complete sequences for 15 putative chorion genes were identified, and grouped into A and B classes.  Phylogenetic analysis revealed that both classes were highly conserved and within each, branches are also species-specific.  Chorion genes from each class were located in pairs on scaffolds of the P. xylostella genome, some of which shared the common promoter regulatory region.  All chorion genes were highly specifically expressed in the P. xylostella adult females, mostly in the ovary with full yolk, which is a crucial period to build the shells of the eggs.  RNAi-based knockdown of chorion-1, which is located on the Px_scaffold 6 alone, although had no effect on yolk deposition, resulted in smaller eggs and sharply reduced hatchability.  Additionally, inhibition of PxCho-1 expression caused a less dense arrangement of the columnar layers, reduced exochorion roughness and shorter microvilli.  Our study provides the foundation for exploring molecular mechanisms of female reproduction in P. xylostella, and for making use of chorion genes as the potential genetic-based molecular target to better control this economically important pest.