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Cotton (Gossypium spp.) is one of the most important fiber crops worldwide. In the last two decades, transgenesis and genome editing have played important roles in cotton improvement. However, genotype dependence is one of the key bottlenecks in generating transgenic and gene‐edited cotton plants through either particle bombardment or Agrobacterium‐mediated transformation. Here, we developed a shoot apical meristem (SAM) cell‐mediated transformation system (SAMT) that allowed the transformation of recalcitrant cotton genotypes including widely grown upland cotton (Gossypium hirsutum), Sea island cotton (Gossypium barbadense), and Asiatic cotton (Gossypium arboreum). Through SAMT, we successfully introduced two foreign genes, GFP and RUBY, into SAM cells of some recalcitrant cotton genotypes. Within 2–3 months, transgenic adventitious shoots generated from the axillary meristem zone could be recovered and grown into whole cotton plants. The GFP fluorescent signal and betalain accumulation could be observed in various tissues in GFP‐ and RUBY‐positive plants, as well as in their progenies, indicating that the transgenes were stably integrated into the genome and transmitted to the next generation. Furthermore, using SAMT, we successfully generated edited cotton plants with inheritable targeted mutagenesis in the GhPGF and GhRCD1 genes through CRISPR/Cas9‐mediated genome editing. In summary, the established SAMT transformation system here in this study bypasses the embryogenesis process during tissue culture in a conventional transformation procedure and significantly accelerates the generation of transgenic and gene‐edited plants for genetic improvement of recalcitrant cotton varieties. [ABSTRACT FROM AUTHOR]

This paper aims at solving the material durability problem caused by spraying deicing salt on pavement concrete in the northern winter. Super absorbent polymer (SAP) was adopted as an internal curing agent to enhance the durability of pavement concrete. Curing parameters including particle size and dosage of SAP and curing condition were optimized based on mortar tests by means of the grey target decision method. The deterioration rule of durability and mechanical properties of pavement concrete internally cured by different SAP dosages after salt freeze–thaw cycles were explored through rapid freeze–thaw test. Combined with the characteristics of pore structure, hydration and microstructure, the influence mechanism of SAP on the salt freeze–thaw resistance of pavement concrete was revealed. The experimental results showed that: (i) The reduction in mass loss rate and relative dynamic modulus was significantly improved by SAP internal curing with moderate dosage; (ii) The more freeze–thaw cycles the specimen underwent, the greater the increase in strength; (iii) After 75 cycles, the chloride ion erosion depth could be decreased by approximately 23.18%. Moreover, the addition of SAP could refine the pore size, inhibit the generation of shrinkage microcracks, and promote the degree of cement hydration in the late stage, which improved the internal density of the cement concrete structure. Therefore, the deterioration of pavement under the coupling effect of salt freeze–thaw was reduced. [ABSTRACT FROM AUTHOR]

To clarify the influencing mechanism of superabsorbent polymer (SAP) internal curing agent on the carbonation resistance of cement concrete, accelerated carbonation experiment was conducted to explore the effect of particle size and dosage of SAP on carbonation depth. The hydration performance of internally cured concrete at different ages was studied by Fourier transform infrared spectroscopy (FTIR) test and X-ray diffraction (XRD) test. Combined with the scanning electron microscope (SEM) test, the hydration filling effect of internal curing on the microstructure of concrete was analyzed; meanwhile, the influence mechanism of SAP on carbonation resistance was revealed. The results showed that (i) when the particle size and dosage of SAP were 100 mesh and 0.200%, the carbonation depth of internally cured concrete was only 56.5% of the control group on day 28; (ii) the Ca(OH)2 absorption peak area of SAP-concrete in the FTIR spectra could be increased by 3.38 times than that of the control group, and more C2S and C3S were translated into Ca(OH)2, which helped to improve the hydration degree of cement concrete; (iii) the hydration products of day 56 were increased significantly and the remaining pores formed by SAP gels were gradually filled by hydration products, which enhanced the compactness and carbonation resistance of cement concrete. [ABSTRACT FROM AUTHOR]

CRISPR/Cas9, Genome-editing, Fluorescence protein, Visualization, Zea mays Keywords: CRISPR/Cas9; Genome-editing; Fluorescence protein; Visualization; Zea mays EN CRISPR/Cas9 Genome-editing Fluorescence protein Visualization Zea mays 872 874 3 05/20/21 20210501 NES 210501 The emerging and promising biotechnology methodology of CRISPR/Cas9 gene editing is revolutionizing crop improvement. [Extracted from the article]

Maize (Zea mays) is one of the most important crops in the world. However, few agronomically important maize genes have been cloned and used for trait improvement, due to its complex genome and genetic architecture. Here, we integrated multiplexed CRISPR/Cas9-based high-throughput targeted mutagenesis with genetic mapping and genomic approaches to successfully target 743 candidate genes corresponding to traits relevant for agronomy and nutrition. After low-cost barcode-based deep sequencing, 412 edited sequences covering 118 genes were precisely identified from individuals showing clear phenotypic changes. The profiles of the associated gene-editing events were similar to those identified in human cell lines and consequently are predictable using an existing algorithm originally designed for human studies. We observed unexpected but frequent homology-directed repair through endogenous templates that was likely caused by spatial contact between distinct chromosomes. Based on the characterization and interpretation of gene function from several examples, we demonstrate that the integration of forward and reverse genetics via a targeted mutagenesis library promises rapid validation of important agronomic genes for crops with complex genomes. Beyond specific findings, this study also guides further optimization of high-throughput CRISPR experiments in plants. [ABSTRACT FROM AUTHOR]

Three genes involved in poly-γ-glutamic acid(γ-PGA)synthesis cloned from Bacillus licheniformis were transformed into cucumber for the first time. Compared with control, its water content increased by 6–14 % and water loss rate decreased by 11–12 %. In zebrafish and human skin experiments, the moisturizing effect of transgenic cucumber was significantly higher than that of CK, γ-PGA and hyaluronic acid group. Transgenic cucumber reduced facial wrinkles and roughness by 19.58 % and 24.97 %, reduced skin melanin content by 5.27 %, increased skin topological angle and L-value by 5.89 % and 2.49 %, and increased the R2 and Q1 values of facial elasticity by 7.67 % and 5.64 %, respectively. The expressions of aqp3 , Tyr , silv and OCA2 were down-regulated, eln1 , eln2 , col1a1a and col1a1b were up-regulated in zebrafish after treated with transgenic cucumber. This study provides an important reference for the endogenous synthesis of important skin care functional molecules in plants. The transgenic cucumber could downregulate the expression of aqp3 that was lead to increasing by the addition of NaCl, prevent the formation of "pores" on the cell membrane, control the water in cells, and lock moisture in the skin; also, it could maintain skin elasticity through upregulating the expression of collagen genes col1a1a and col1a1b and the elastin genes eln1 and eln2 ; further, it could improve skin tone through downregulating the genes of tyr , silv and oca2 in the process of the formation of melanin. [Display omitted] • Cucumber successfully synthesized γ-PGA heterologously, and the normal growth of cucumber was not affected. • Its water content increased by 6~14% and water loss rate decreased by 11-12% owing to the heterologous γ-PGA. • Its skin-moisturizing, anti-wrinkle, and whitening effects surpassed those of wild-type and γ-PGA controls significantly. • The transgenic cucumber's skin moisturizing, anti-wrinkle, and whitening enhancement mechanism was confirmed in zebrafish. [ABSTRACT FROM AUTHOR]

Summary: Low grain moisture at harvest is crucial for safe production, transport and storage, but the genetic architecture of this trait in maize (Zea mays) remains elusive. Here, we measured the dynamic changes in grain moisture content in an association‐mapping panel of 513 diverse maize inbred lines at five successive stages across five geographical environments. Genome‐wide association study (GWAS) revealed 71 quantitative trait loci (QTLs) that influence grain moisture in maize. Epistatic effects play vital roles in the variability in moisture levels, even outperforming main‐effect QTLs during the early dry‐down stages. Distinct QTL–environment interactions influence the spatio‐temporal variability of maize grain moisture, which is primarily triggered at specific times. By combining genetic population analysis, transcriptomic profiling and gene editing, we identified GRMZM5G805627 and GRMZM2G137211 as candidate genes underlying major QTLs for grain moisture in maize. Our results provide insights into the genetic architecture of dynamic changes in grain moisture, which should facilitate maize breeding. [ABSTRACT FROM AUTHOR]

Summary: The nutritional traits of maize kernels are important for human and animal nutrition, and these traits have undergone selection to meet the diverse nutritional needs of humans. However, our knowledge of the genetic basis of selecting for kernel nutritional traits is limited. Here, we identified both single and epistatic quantitative trait loci (QTLs) that contributed to the differences of oil and carotenoid traits between maize and teosinte. Over half of teosinte alleles of single QTLs increased the values of the detected oil and carotenoid traits. Based on the pleiotropism or linkage information of the identified single QTLs, we constructed a trait–locus network to help clarify the genetic basis of correlations among oil and carotenoid traits. Furthermore, the selection features and evolutionary trajectories of the genes or loci underlying variations in oil and carotenoid traits revealed that these nutritional traits produced diverse selection events during maize domestication and improvement. To illustrate more, a mutator distance–relative transposable element (TE) in intron 1 of DXS2, which encoded a rate‐limiting enzyme in the methylerythritol phosphate pathway, was identified to increase carotenoid biosynthesis by enhancing DXS2 expression. This TE occurs in the grass teosinte, and has been found to have undergone selection during maize domestication and improvement, and is almost fixed in yellow maize. Our findings not only provide important insights into evolutionary changes in nutritional traits, but also highlight the feasibility of reintroducing back into commercial agricultural germplasm those nutritionally important genes hidden in wild relatives. Significance Statement: The identification and selection‐feature characterization of genetic loci contributing to nutritional trait variation between maize and teosinte is of fundamental importance in understanding the evolutionary interface between plant and human. Most favorable alleles associated with nutritional traits exist in teosinte and are not fixed in modern maize, underscoring the potential benefit of introducing teosinte alleles during maize breeding regimens to yield hybrids with desirable nutritional traits. [ABSTRACT FROM AUTHOR]

An AGAMOUS ( AG)-like gene, GbAGL2, was isolated from Gossypium barbadense and characterized. Alignment and phylogenetic analysis indicated that GbAGL2 shared high homology with AG-subfamily genes and belonged to a C-class gene family. DNA gel blot analysis showed that GbAGL2 belonged to a low-copy gene family. Reverse transcriptase-polymerase chain reaction (RT-PCR) and quantitative real-time PCR (qPCR) revealed that GbAGL2 was highly expressed in reproductive tissues including ovules and carpels, but barely expressed in vegetative tissues. In addition, GbAGL2 expression in a cotton cultivar XuZhou142 (wt) (XZ142, G. hirsutum L.) and its fibreless mutant XZ142 (fl) was examined. RNA in situ hybridization analysis indicated that GbAGL2 transcripts were preferentially restricted to outer ovule integuments, carpels and fibres. These expression patterns implied that GbAGL2 might participate in the development of the carpel and ovule. Furthermore, Arabidopsis transformation was performed and modifications occurred in flowers, and the silique length of transgenic plants also increased slightly, suggesting that the GbAGL2 gene may have a positive effect on the development of the ovary or ovule. Our findings suggest that GbAGL2 might not only specify the identity of floral organs but also play a potential key role in ovary or fibre development in cotton. [ABSTRACT FROM AUTHOR]