Identification of two major QTLs for pod shell thickness in peanut (Arachis hypogaea L.) using BSA-seq analysis.

BACKGROUND: Pod shell thickness (PST) is an important agronomic trait of peanut because it affects the ability of shells to resist pest infestations and pathogen attacks, while also influencing the peanut shelling process. However, very few studies have explored the genetic basis of PST. RESULTS: An F2 segregating population derived from a cross between the thick-shelled cultivar Yueyou 18 (YY18) and the thin-shelled cultivar Weihua 8 (WH8) was used to identify the quantitative trait loci (QTLs) for PST. On the basis of a bulked segregant analysis sequencing (BSA-seq), four QTLs were preliminarily mapped to chromosomes 3, 8, 13, and 18. Using the genome resequencing data of YY18 and WH8, 22 kompetitive allele-specific PCR (KASP) markers were designed for the genotyping of the F2 population. Two major QTLs (qPSTA08 and qPSTA18) were identified and finely mapped, with qPSTA08 detected on chromosome 8 (0.69-Mb physical genomic region) and qPSTA18 detected on chromosome 18 (0.15-Mb physical genomic region). Moreover, qPSTA08 and qPSTA18 explained 31.1-32.3% and 16.7-16.8% of the phenotypic variation, respectively. Fifteen genes were detected in the two candidate regions, including three genes with nonsynonymous mutations in the exon region. Two molecular markers (Tif2_A08_31713024 and Tif2_A18_7198124) that were developed for the two major QTL regions effectively distinguished between thick-shelled and thin-shelled materials. Subsequently, the two markers were validated in four F2:3 lines selected. CONCLUSIONS: The QTLs identified and molecular markers developed in this study may lay the foundation for breeding cultivars with a shell thickness suitable for mechanized peanut shelling.

AhNPR3 regulates the expression of WRKY and PR genes, and mediates the immune response of the peanut (Arachis hypogaea L.).

Systemic acquired resistance is an essential immune response that triggers a broad-spectrum disease resistance throughout the plant. In the present study, we identified a peanut lesion mimic mutant m14 derived from an ethyl methane sulfonate-mutagenized mutant pool of peanut cultivar "Yuanza9102." Brown lesions were observed in the leaves of an m14 mutant from seedling stage to maturity. Using MutMap together with bulked segregation RNA analysis approaches, a G-to-A point mutation was identified in the exon region of candidate gene Arahy.R60CUW, which is the homolog of AtNPR3 (Nonexpresser of PR genes) in Arabidopsis. This point mutation caused a transition from Gly to Arg within the C-terminal transactivation domain of AhNPR3A. The mutation of AhNPR3A showed no effect in the induction of PR genes when treated with salicylic acid. Instead, the mutation resulted in upregulation of WRKY genes and several PR genes, including pathogenesis-related thaumatin- and chitinase-encoding genes, which is consistent with the resistant phenotype of m14 to leaf spot disease. Further study on the AhNPR3A gene will provide valuable insights into understanding the molecular mechanism of systemic acquired resistance in peanut. Moreover, our results indicated that a combination of MutMap and bulked segregation RNA analysis is an effective method for identifying genes from peanut mutants.

Hydrogen sulfide inhibits human T-cell leukemia virus type-1 (HTLV-1) protein expression via regulation of ATG4B.

Hydrogen sulfide (H2 S) is a redox gasotransmitter. It has been shown that H2 S has a key role in host antiviral defense by inhibiting interleukin production and S-sulfhydrating Keap1 lead to Nrf2/ARE pathway activation. However, it is yet unclear whether H2 S can play an antiviral role by regulating autophagy. In this study, we found that exogenous H2 S decreased the expression of human T-cell leukemia virus type-1 (HTLV-1) protein and HTLV-1 induced autophagosomes accumulation. Transmission electron microscope assays indicated that autophagosomes accumulation decreased after H2 S administration. HTLV-1-transformed T-cell lines had a high level of CSE (H2 S endogenous enzyme) which could be induced in Hela by HTLV-1 infection. Immunoblot demonstrated that overexpression of CSE inhibited HTLV-1 protein expression and autophagy. And we got the opposite after CSE knockdown. Meanwhile, H2 S could not restrain the autophagy when ATG4B had a mutant at its site of 89. In a word, these results suggested that H2 S modulated HTLV-1 protein expression via ATG4B. Therefore, our findings suggested a new mechanism by which H2 S defended against virus infection.

Implementing an Air Suction Effect Induction Strategy to Create Super Thermally Insulating and Superelastic SiC Aerogels.

Silicon carbide (SiC) aerogels are promising thermal insulators that are lightweight and possess high thermal stability. However, their application is hindered by their brittleness. Herein, an air suction effect induction (ASEI) strategy is proposed to fabricate a super thermally insulating SiC aerogel (STISA). The ASEI strategy exploits the air suction effect to subtly regulate the directional flow of the SiO gas, which can induce directional growth and assembly of SiC nanowires to form a directional lamellar structure. The sintering time is significantly reduced by >90%. Significant improvements in the compression and elasticity performance of the STISA are achieved upon the formation of a directional lamellar structure through the ASEI strategy. Moreover, the lamellar structure endows the STISA with an ultralow thermal conductivity of 0.019 W m-1 K-1 . The ASEI strategy paves the way for structural design of advanced ceramic aerogels for super thermal insulation.

QTL mapping of web blotch resistance in peanut by high-throughput genome-wide sequencing.

BACKGROUND: Web blotch is one of the most important foliar diseases worldwide in peanut (Arachis hypogaea L.). The identification of quantitative trait loci (QTLs) for peanut web blotch resistance represents the basis for gene mining and the application of molecular breeding technologies. RESULTS: In this study, a peanut recombinant inbred line (RIL) population was used to map QTLs for web blotch resistance based on high-throughput genome-wide sequencing. Frequency distributions of disease grade and disease index in five environments indicated wide phenotypic variations in response to web blotch among RILs. A high-density genetic map was constructed, containing 3634 bin markers distributed on 20 peanut linkage groups (LGs) with an average genetic distance of 0.5 cM. In total, eight QTLs were detected for peanut web blotch resistance in at least two environments, explaining from 2.8 to 15.1% of phenotypic variance. Two major QTLs qWBRA04 and qWBRA14 were detected in all five environments and were linked to 40 candidate genes encoding nucleotide-binding site leucine-rich repeat (NBS-LRR) or other proteins related to disease resistances. CONCLUSIONS: The results of this study provide a basis for breeding peanut cultivars with web blotch resistance.

Expanded newborn screening for inborn errors of metabolism by tandem mass spectrometry in newborns from Xinxiang city in China.

BACKGROUND: Tandem mass spectrometry is a powerful technology available in China over the last 15 years. The development of tandem mass spectrometry had made it possible to rapidly screen newborns for inborn errors of metabolism. The aim of this study was to determine the birth incidence of inborn errors of metabolism through expanded screening of newborns by tandem mass spectrometry in Xinxiang area. METHODS: Dried blood spots from 50 112 newborns were assessed for inborn errors of metabolism by tandem mass spectrometry. The diagnoses were confirmed based on the clinical features, conventional laboratory tests, and the organic acid levels tested in urine by gas chromatography-mass spectrometry. RESULTS: The study findings revealed that 31 newborns were diagnosed with inborn errors of metabolism. The total incidence rate of inborn errors of metabolism was 1/1617, and these included 16 cases of amino acid disorders (51.6%), nine cases of organic acid disorders (29.0%), and 6 (19.4%) cases of fatty acid beta-oxidation disorders. CONCLUSIONS: The screening for the incidence of inborn errors of metabolism in Xinxiang area showed that the rate was higher than previously reported. This study provides valuable data which may be useful in facilitating improvements in the expansion of screening to enable early diagnosis and treatment of inborn errors of metabolism before the onset of symptoms.

Marker-assisted backcrossing to improve seed oleic acid content in four elite and popular peanut (Arachis hypogaea L.) cultivars with high oil content.

High oleic acid composition is an important determinant of seed quality in peanut (Arachis hypogaea) in regard to its nutritional benefits for human health and prolonged shelf-life for peanut products. To improve the oleic acid content of popular peanut cultivars in China, four peanut cultivars of different market types were hybridized with high-oleic-acid donors and backcrossed for four generations as recurrent parents using fad2 marker-assisted backcross selection. Seed quality traits in advanced generations derived by selfing were assessed using near-infrared reflectance spectroscopy for detection of oleic acid and Kompetitive allele-specific PCR (KASP) screening of fad2 mutant markers. Twenty-four high-oleic-acid lines of BC4F4 and BC4F5 populations, with morphological features and agronomic traits similar to those of the recurrent parents, were obtained within 5 years. The genetic backgrounds of BC4F5 lines were estimated using the KASP assay, which revealed the genetic background recovery rate was 79.49%-92.31%. The superior lines raised are undergoing a multi-location test for cultivar registration and release. To our knowledge, this is the first application of single nucleotide polymorphism markers based on the high-throughput and cost-effective KASP assay for detection of fad2 mutations and genetic background evaluation in a peanut breeding program.

High-resolution chromosome painting with repetitive and single-copy oligonucleotides in Arachis species identifies structural rearrangements and genome differentiation.

BACKGROUND: Arachis contains 80 species that carry many beneficial genes that can be utilized in the genetic improvement of peanut (Arachis hypogaea L. 2n = 4x = 40, genome AABB). Chromosome engineering is a powerful technique by which these genes can be transferred and utilized in cultivated peanut. However, their small chromosomes and insufficient cytological markers have made chromosome identification and studies relating to genome evolution quite difficult. The development of efficient cytological markers or probes is very necessary for both chromosome engineering and genome discrimination in cultivated peanut. RESULTS: A simple and efficient oligonucleotide multiplex probe to distinguish genomes, chromosomes, and chromosomal aberrations of peanut was developed based on eight single-stranded oligonucleotides (SSONs) derived from repetitive sequences. High-resolution karyotypes of 16 Arachis species, two interspecific F1 hybrids, and one radiation-induced M1 plant were then developed by fluorescence in situ hybridization (FISH) using oligonucleotide multiplex, 45S and 5S rDNAs, and genomic in situ hybridization (GISH) using total genomic DNA of A. duranensis (2n = 2x = 20, AA) and A. ipaënsis (2n = 2x = 20, BB) as probes. Genomes, chromosomes, and aberrations were clearly identifiable in the established karyotypes. All eight cultivars had similar karyotypes, whereas the eight wild species exhibited various chromosomal variations. In addition, a chromosome-specific SSON library was developed based on the single-copy sequence of chromosome 6A of A. duranensis. In combination with repetitive SSONs and rDNA FISH, the single-copy SSON library was applied to identify the corresponding A3 chromosome in the A. duranensis karyotype. CONCLUSIONS: The development of repetitive and single-copy SSON probes for FISH and GISH provides useful tools for the differentiation of chromosomes and identification of structural chromosomal rearrangement. It facilitates the development of high-resolution karyotypes and detection of chromosomal variations in Arachis species. To our knowledge, the methodology presented in this study demonstrates for the first time the correlation between a sequenced chromosome region and a cytologically identified chromosome in peanut.

Research on the Relationship between the Amylopectin Structure and the Physicochemical Properties of Starch Extracted from Glutinous Rice.

Glutinous rice has very low amylose content and is a good material for determining the structure and physicochemical properties of amylopectin. We selected 29 glutinous rice varieties and determined the amylopectin structure by high-performance anion exchange chromatography with the pulsed amperometric detection method. We also determined the correlation between amylopectin structure and the physicochemical properties of starch extracted from these varieties. The results showed that the amylopectin chain ratio Σdegree of polymerization (DP) ≤ 11/ΣDP ≤ 24 of 29 glutinous rice varieties was greater than 0.26, signifying that these varieties contained type II amylopectin. The results of the correlation analysis with gelatinization temperature showed that ΣDP 6-11 was significantly negatively correlated with the onset gelatinization temperature (GT) (TO), peak GT (TP), and conclusion GT (TC). Among the thermodynamic properties, ΣDP 12-24 was significantly positively correlated with To, Tp, and Tc, ΣDP 25-36 was significantly negatively correlated with To, Tp, and Tc, and ΣDP ≥ 37 had no correlation with the thermodynamic properties. The results of correlation analysis with RVA spectrum characteristic values showed that ΣDP 6-11 was significantly negatively correlated with hot paste viscosity (HPV), cool paste viscosity (CPV), consistency viscosity (CSV), peak time (PeT), and pasting temperature (PaT) among the Rapid Visco Analyzer (RVA) profile characteristics, ΣDP 12-24 was significantly positively correlated with HPV, CPV, CSV, PeT, and PaT, and ΣDP ≥ 25 had no correlation with the viscosity characteristics. Therefore, we concluded that the amylopectin structure had a greater effect on the TO, TP, TC, ΔH and peak viscosity, HPV, CPV, CSV, PeT, and PaT. The glutinous rice varieties with a higher distribution of short chains and a lower distribution of medium and long chains in the amylopectin structure resulted in lower GT and RVA spectrum characteristic values.

Effects of Neutron and Gamma Rays Combined Irradiation on the Transcriptional Profile of Human Peripheral Blood.

We studied the effects of neutrons, neutrons and γ rays, and γ rays exposures on the transcription spectrum in human peripheral blood of three healthy adult men. Samples were irradiated with 1.42 Gy 2.5-MeV neutrons, 0.71 Gy neutrons and 0.71 Gy 137Cs γ rays, and 1.42 Gy 137Cs γ rays. Transcriptome sequencing identified 56 differentially co-expressed genes and enriched 26 KEGG pathways. There are 97, 45 and 30 differentially expressed genes in neutron, neutron and γ ray combined treatment, and γ rays, respectively, and 21, 3 and 8 KEGG pathways with significant differences are enriched. Fluorescence quantitative polymerase chain reaction (qPCR) verified differential co-expression of AEN, BAX, DDB2, FDXR, and MDM2. Additionally, irradiation of AHH-1 human lymphocytes with a 252Cf neutron source at 0, 0.14, 0.35, and 0.71 Gy, fluorescence qPCR revealed a dose-response relationship for BAX, DDB2, and FDXR at dose ranges of 0-0.71 Gy, with R2 of 0.803, 0.999, and 0.999, respectively. Thus, neutrons can induce more differentially expressed genes and enrich more pathways. Combined treatment of neutrons and γ-rays may incorporate damage of both high and low LET, the genes activated by neutrons and γ rays combined are almost the combination of genes activated by neutron and γ rays combined treatment. BAX, DDB2 and FDXR are differentially expressed after irradiation by Deuterium-Deuterium (D-D) neutron source and 252Cf neutron source, so they are expected to be molecular targets of neutron damage.

Gut microbiota of two invasive fishes respond differently to temperature.

Temperature variation structures the composition and diversity of gut microbiomes in ectothermic animals, key regulators of host physiology, with potential benefit to host or lead to converse results (i.e., negative). So, the significance of either effect may largely depend on the length of time exposed to extreme temperatures and how rapidly the gut microbiota can be altered by change in temperature. However, the temporal effects of temperature on gut microbiota have rarely been clarified. To understand this issue, we exposed two juvenile fishes (Cyprinus carpio and Micropterus salmoides), which both ranked among the 100 worst invasive alien species in the world, to increased environmental temperature and sampled of the gut microbiota at multiple time points after exposure so as to determine when differences in these communities become detectable. Further, how temperature affects the composition and function of microbiota was examined by comparing predicted metagenomic profiles of gut microbiota between treatment groups at the final time point of the experiment. The gut microbiota of C. carpio was more plastic than those of M. salmoides. Specifically, communities of C. carpio were greatly altered by increased temperature within 1 week, while communities of M. salmoides exhibit no significant changes. Further, we identified 10 predicted bacterial functional pathways in C. carpio that were temperature-dependent, while none functional pathways in M. salmoides was found to be temperature-dependent. Thus, the gut microbiota of C. carpio was more sensitive to temperature changes and their functional pathways were significantly changed after temperature treatment. These results showed the gut microbiota of the two invasive fishes differ in response to temperature change, which may indicate that they differ in colonization modes. Broadly, we have confirmed that the increased short-term fluctuations in temperatures are always expected to alter the gut microbiota of ectothermic vertebrates when facing global climate change.

Localization of high level of sequence conservation and divergence regions in cotton.

In a previous study, we observed that the variations in chromosome size are due to uneven expansion and contraction by comparing the structures and sizes of a pair of homoeologous high-resolution cytogenetic maps of chromosomes 12A and 12D in tetraploid cotton. To reveal the variation at the sequence level, in the present paper, we sequenced two pairs of homoeologous bacterial artificial chromosomes derived from high- to low-variable genomic regions. Comparisons of their sequence variations confirmed that the highly conserved and divergent sequences existed in the distal and pericentric regions, e.g., high- and low-variable genome size regions in these two pairs of cotton homoeologous chromosomes. Sequence analysis also confirmed that the differential accumulation of Gossypium retrotransposable gypsy-like element (Gorge3) accounted for the main contributions for the size difference between the pericentric regions. By fluorescence in situ hybridization analysis, we found that Gorge3 has a bias distribution in the A(T)/A proximal regions and is associated with the heterochromatin along the chromosomes in the entire Gossypium genome. These results indicate that, between A(T)/A and D(T)/D genomes, the distal and pericentric regions usually possess high level of sequence conservation and divergence, respectively, in cotton.

Transvaginal color Doppler sonography predicts ovarian interstitial fibrosis and microvascular injury in women with ovarian endometriotic cysts.

OBJECTIVE: To determine novel predictors of ovarian interstitial fibrosis and microvascular injury associated with ovarian endometriotic cysts (OECs). DESIGN: Case-control study. SETTING: The gynecology unit of an affiliated hospital in China. POPULATION: Women <40 years of age with OECs or benign ovarian tumors (controls). METHODS: Transvaginal color Doppler sonography was performed preoperatively to detect ovarian interstitial flow. Postoperatively, expressions of transforming growth factor-ß1 (TGF-ß1) and thrombospondin-1 (TSP-1), as well as microvessel density in ovarian interstitial, were analyzed using immunohistochemistry. MAIN OUTCOME AND MEASURES: Ovarian interstitial flow and expressions of TGF-ß1, TSP-1, and microvessel density. RESULTS: Compared with controls, ovarian interstitial flow in the study group was decreased and arterial spectra indicated significantly higher resistance indices. Microvessel density was reduced, but TGF-ß1 and TSP-1 were elevated in the study group. There was a positive correlation between TGF-ß1 and TSP-1. There were negative correlations between TGF-ß1 and microvessel density, and between TSP-1 and microvessel density. Microvessel density and resistance indices were negatively correlated, whereas the correlations of TGF-ß1 and TSP-1 with resistance indices were positive. CONCLUSIONS: Resistance indices are consistent with pathological indices. Changes in resistance indices in ovaries with endometriosis are related to interstitial fibrosis and microvascular injury.

Ovarian interstitial blood flow changes assessed by transvaginal colour Doppler sonography: predicting ovarian endometrioid cyst-induced injury to ovarian interstitial vessels.

PURPOSE: To evaluate the blood flow changes and their relationships to microvessel density (MVD) and thrombospondin-1 (TSP-1) by transvaginal colour Doppler sonography (TV-CDS) in the ovarian interstitium to predict ovarian interstitial microvascular injury in the pathological process of ovarian endometrial cysts (OEC). METHODS: TV-CDS was preoperatively performed to detect blood flow changes in 60 patients with 76 ovarian endometrioid cysts, and flow classification and resistance indices (RI) values were recorded for analysis. Ovarian interstitial specimens with blood flow signals were collected for postoperative pathologic examination. TSP-1 protein was evaluated by immunohistochemistry and Western blot, TSP-1 mRNA by reverse transcriptase polymerase chain reaction, microvessels by CD34 antibody, and MVD by image analysis. Thirty age-matched patients with benign ovarian tumours served as controls. RESULTS: Blood flow, most of star-shaped, within ovarian interstitial arteries in the OEC group was diminished; however, arterial spectra exhibited a high-resistance flow manifesting a significantly higher RI compared with that of the control group (P < 0.01). In ovarian interstitial specimens, there were significantly (P < 0.01) lower CD34-MVD and higher TSP-1 protein and mRNA in the OEC group than in the controls. CD34-MVD and TSP-1 showed remarkably negative correlation (rs = -0.76, P < 0.01). RI values correlated negatively with MVD values (rs = -0.91, P < 0.01), but positively with TSP-1 (rs = 0.81, P < 0.01), while flow classification correlated positively with MVD values (rs = 0.66, P < 0.01), but negatively with TSP-1 (rs = -0.54, P < 0.01). CONCLUSIONS: Changes in CD34-MVD and TSP-1 reflected ovarian interstitial microvascular injury of OEC, pathologically supported the findings of blood flow changes within ovarian interstitial arteries, and prospectively predicted OEC-induced ovarian interstitial vessel injury. This has important clinical value: early treatment, instead of allowing the cyst to become bigger, is of great importance for OEC patients, because a greater number of functional tissue blood vessels would be destroyed as the disease progresses.

Effects of Cellulase and Lactobacillus plantarum on Fermentation Quality, Chemical Composition, and Microbial Community of Mixed Silage of Whole-Plant Corn and Peanut Vines.

Significant anaerobic fermentation occurs in silage through the action of anaerobic bacteria. The objective of this study was to evaluate the effects of cellulase and Lactobacillus plantarum on the fermentation quality and bacterial community of whole-plant corn and peanut vine mixed silage. Mixed silage was tested with no addition (CK), addition of Lactobacillus plantarum (LP), addition of cellulase (CE), and the simultaneous addition of Lactobacillus plantarum and cellulase (LPCE). LPCE samples exhibited decreased pH; decreased content of acetic acid, propionic acid, and butyric acid; and increased content of lactic acid. LP and LPCE had better effects on chemical composition than CK and CE, especially in decreasing acid detergent fiber and neutral detergent fiber content. High-throughput sequencing identified Lactobacillus, Klebsiella, Serratia, and Weissella as the main microorganisms. LP and CE increased the abundance of Acetobacter, and LPCE decreased the abundance of Acetobacter. All additives decreased the abundance of Weissella, Leuconostoc, and Lactococcus, and increased the abundance of Pantoea. Overall, simultaneous addition of cellulase and Lactobacillus plantarum helped to improve the quality of mixed silage of whole-plant corn and peanut vines.

Mechanically Strong and Tailorable Polyimide Aerogels Prepared with Novel Silicone Polymer Crosslinkers.

Polyimide (PI) aerogels were prepared using self-designed silicone polymer cross-linkers with multi-amino from low-cost silane coupling agents to replace conventional small-molecule cross-linkers. The long-chain structure of silicone polymers provides more crosslinking points than small-molecule cross-linkers, thus improving the mechanical properties of polyimide. To investigate the effects of amino content and degree of polymerization on the properties of silicone polymers, the different silicone polymers and their cross-linked PI aerogels were prepared. The obtained PI aerogels exhibit densities as low as 0.106 g/cm3 and specific surface areas as high as 314 m2/g, and the maximum Young's modulus of aerogel is up to 20.9 MPa when using (T-20) as cross-linkers. The cross-linkers were an alternative to expensive small molecule cross-linkers, which can improve the mechanical properties and reduce the cost of PI aerogels.

High Performance and Self-Humidifying of Novel Cross-Linked and Nanocomposite Proton Exchange Membranes Based on Sulfonated Polysulfone.

The introduction of inorganic additive or nanoparticles into fluorine-free proton exchange membranes (PEMs) can improve proton conductivity and have considerable effects on the performance of polymer electrolyte membrane fuel cells. Based on the sol-gel method and in situ polycondensation, novel cross-linked PEM and nanocomposite PEMs based on a sulfonated polysulfone (SPSU) matrix were prepared by introducing graphene oxide (GO) polymeric brushes and incorporating Pt-TiO2 nanoparticles into an SPSU matrix, respectively. The results showed that the incorporation of Pt-TiO2 nanoparticles could obviously enhance self-humidifying and thermal stability. In addition, GO polymer brushes fixed on polymeric PEM by forming a cross-linked network structure could not only solve the leakage of inorganic additives during use and compatibility problem with organic polymers, but also significantly improve proton conductivity and reduce methanol permeability of the nanocomposite PEM. Proton conductivity, water uptake and methanol permeability of the nanocomposite PEM can be up to 6.93 mS cm-1, 46.58% and be as low as 1.4157 × 10-6 cm2 s-1, respectively, which represent increases of about 70%, about 22% and a decrease of about 40%, respectively, compared with that of primary SPSU. Therefore, the synergic action of the covalent cross-linking, GO polymer brush and nanoparticles can significantly and simultaneously improve the overall performance of the composite PEM.

Improvement of the Thermal Insulation Performance of Silica Aerogel by Proper Heat Treatment: Microporous Structures Changes and Pyrolysis Mechanism.

A simple heat treatment method was used to optimize the three-dimensional network structure of the hydrophobic aerogel, and during the heat treatment process at 200-1000 °C, the thermal conductivity of the aerogel reached the lowest to 0.02240 W/m·K between 250 °C and 300 °C, which was mainly due to the optimization of microstructure and pyrolysis of surface groups. Further Fluent heat-transfer simulation also confirmed the above results. Synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) was used to finely measure the pyrolysis process of aerogels, and the pyrolysis process of aerogel was divided into four stages. (I) Until 419 °C, as the temperature continued to rise, surface methyl groups were oxidized to form hydroxyl. (II) As the temperature reached to 232 °C, the oxidation proceeded. In addition, inside the aerogel, because of lacking oxygen, the reaction produced CH4 and C-Si bonds would form. (III) After 283 °C, Si-OH groups began to condense to form Si-O-Si, which optimized the three-dimensional network structures to be beneficial to improve the thermal insulation performance of silica aerogel. (IV) When it reached 547 °C, the chemical reaction was terminated, and all the primary particles gradually fused into secondary particles and sintered to form clusters.

Transcriptome analysis of pod mutant reveals plant hormones are important regulators in controlling pod size in peanut (Arachis hypogaea L.).

Pod size is an important yield-influencing trait in peanuts. It is affected by plant hormones and identifying the genes related to these hormones may contribute to pod-related trait improvements in peanut breeding programs. However, there is limited information on the molecular mechanisms of plant hormones that regulate pod size in peanuts. We identified a mutant with an extremely small pod (spm) from Yuanza 9102 (WT) by 60Co γ-radiation mutagenesis. The length and width of the natural mature pod in spm were only 71.34% and 73.36% of those in WT, respectively. We performed comparative analyses for morphological characteristics, anatomy, physiology, and global transcriptome between spm and WT pods. Samples were collected at 10, 20, and 30 days after peg elongation into the soil, representing stages S1, S2, and S3, respectively. The differences in pod size between WT and spm were seen at stage S1 and became even more striking at stages S2 and S3. The cell sizes of the pods were significantly smaller in spm than in WT at stages S1, S2, and S3. These results suggested that reduced cell size may be one of the important contributors for the small pod in spm. The contents of indole-3-acetic acid (IAA), gibberellin (GA), and brassinosteroid (BR) were also significantly lower in spm pods than those in WT pods at all three stages. RNA-Seq analyses showed that 1,373, 8,053, and 3,358 differently expressed genes (DEGs) were identified at stages S1, S2, and S3, respectively. Functional analyses revealed that a set of DEGs was related to plant hormone biosynthesis, plant hormone signal transduction pathway, and cell wall biosynthesis and metabolism. Furthermore, several hub genes associated with plant hormone biosynthesis and signal transduction pathways were identified through weighted gene co-expression network analysis. Our results revealed that IAA, GA, and BR may be important regulators in controlling pod size by regulating cell size in peanuts. This study provides helpful information for the understanding of the complex mechanisms of plant hormones in controlling pod size by regulating the cell size in peanuts and will facilitate the improvement of peanut breeding.