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Key points logEs is proportional to 2.0ML for the Shoufeng earthquake sequence in Taiwan. A crossover magnitude detected at ML = 4.0 divides the MW–ML relation into two parts. For ML > 4.0, logM0 ∝ 0.67ML and MW ∝ ML; for ML

Through forward multiple-event analysis of teleseismic P-waves using source time functions (STFs), derived by non-negative time-domain deconvolution, we inferred the rupture features of the 2018 Hualien earthquake. At least six sub-events composed the Hualien earthquake, with the largest one (corresponding to Mw = 6.3) occurring 4.8 s later than the initiation of rupture. The total seismic moment (M0) of 6.48 × 1018 Nm (Mw = 6.5) and radiated seismic energy (ES) of 1.76 × 1014 Nm led to the ES/M0 ratio ~2.72 × 10-5. A static stress drop (ΔσS) of 5.03 MPa was also derived for the earthquake. On average, the rupture parameters of the 2018 Hualien earthquake from this study were similar to globally average values. From M0 and source duration (10.9 s), this implied an average rupture velocity (Vr) less than 2.0 km s-1. The forward multiple-event modeling showed that ΔσS varied with the sub-events and increased with ES/M0 to imply the frictional strength being heterogeneous along the fault. From the highest STF peak (6.9 s after the initiation) near the land-sea interface, we suggested that the Hualien earthquake be divided into two rupture processes. One with low ΔσS, low ES/M0, and high Vr occurred at sea; the other with high ΔσS, high ES/M0, and low Vr occurred on land. Both seawater and local velocity structures probably played crucial factors behind these rupture discrepancies during the 2018 Hualien earthquake.

Heat stress is an essential factor affecting maize growth and yield formation. The exploration and mechanism analysis of related tolerance genes is an important field for breeding maize heat stress tolerant varieties. However, there is few study in this aspect. In this study, we identified a nuclear factor ZmNF-YC13 associated with heat stress response, and its encoding gene expression was rapidly induced by high temperature and osmotic stress. The promoter of Arabidopsis thaliana heat stress-inducible expression gene AtHSP70 was used to drive ZmNF-YC13 and the heat-inducible expression maize material of ZmNF-YC13 (HSP21Pro:ZmNF-YC13-myc) was successfully screened. Phenotypic analysis after high temperature treatment demonstrated that leaf length, leaf width, shoot thickness, fresh and dry weight of shoot and root were significantly higher than wild type. The relative expression level showed that ZmNF-YC13 could enhance the inducible level of downstream heat stress response genes in response to heat stress. Luciferase reporter assay and ChIP-qPCR assay also revealed that ZmNF-YC13 could regulate the expression of heat stress transcription factor ZmHsfA2c. These results confirmed preliminarily that ZmNF-YC13 could improve the heat tolerance of maize by regulating downstream heat stress response genes, which could provide a theoretical basis for marker-assisted selection and germplasm identification using the polymorphism of this locus. [ABSTRACT FROM AUTHOR]

Maize kernel is closely related to yield and nutritive quality. Study on the function of maize kernel development relative genes provides important basis for the molecular mechanism analysis, yield increasing and nutritive quality improving. B73 pollen was treated with ethyl methylmethanesulfonate (EMS) and a defective maize kernel defective kernel 54 (dek54) was screened. dek54 had small mature kernel, wrinkled and whitened seed coat phenotype. Genetic analysis indicated that dek54 is a recessive mutant controlled by a single gene. Paraffin sections showed starchy endosperm cells of dek54 had irregular shape and dense arrangement at developmental stage. Scanning electron microscopy observation indicated that protein bodies around starch granules in the central region of the dek54 mature kernel endosperm were fewer and arranged more loosely compare to wild type. Total protein, zein, amino acids components contents and total nitrogen content of dek54 mature kernel were significantly lowered compared with the wild type. dek54 was located on chromosome 7 within the interval of the physical distance of about 290 kb between markers SSR6 and SSR7. Sequencing revealed that the 351th base G on the 2nd exon of Zm00001d019294 gene changed into A, which led to the premature termination of the protein translation. Zm00001d019294 gene was specifically expressed in immature maize kernel, and has the highest expression in 12 DAP (days after pollination) immature kernel. Targeted mutation was performed using CRISPR/Cas9 system to identify that mutant phenotype was caused by candidate gene Zm00001d019294. Dek54 encoded an MFS (major facilitator superfamily) protein and had high homology with ZmNRT1.5 (nitrate transporter). Besides, Dek54 protein was localized in the plasma membrane of maize protoplasts. The study of dek54 laid the foundation for the molecular mechanism analysis of maize kernel development. [ABSTRACT FROM AUTHOR]

Plasma membrane intrinsic protein (PIP) is one of the main subfamily of aquaporin regulates diverse physiology functions during plant growth and development. In previous research, the expression of ZmPIP1;1 was induced by osmosis or salt stress. However, the biological function of ZmPIP1;1 was still unclear in maize. In this study, ZmPIP1;1 overexpressed transgenic plants were obtained and exhibited less water loss rate and enhanced drought tolerance compared to wild type. Transcriptome sequencing indicated significant changes in the expression levels of genes involved in ABA biosynthesis and its signaling pathways. Photosynthetic activity, kernel width and kernel weight was increased in ZmPIP1;1 overexpression maize, but not growth under normal condition compared with wild type. Moreover, interaction between ZmPIP1;1 and ZmPIP2;6 was observed by bi-molecular fluorescence complementation (BiFC) experiment, resulting in re-localized on plasma membrane and chloroplast in maize mesophyll protoplast. Our study laid an important foundation for understanding the molecular mechanism of ZmPIP1;1, and provided a new method of molecular breeding for high photosynthetic efficiency. [ABSTRACT FROM AUTHOR]

The phosphorus uptake (PU) in above-ground parts of plant, root characteristics and root exudations as well as the quantitative trait loci (QTLs) associated with these characteristics were determined for a F2:3 population derived from the cross of two contrasting maize (Zea mays L.) genotypes, 082 and Ye107. A total of 241 F2:3 families were evaluated in replicated trials under deficient phosphorus conditions in 2007 at two sites (Kaixian County and Southwest University, Chongqing, P. R. China). The results show pleiotropy and close linkage among QTLs. Four common regions in different environments were in bnlg100- bnlg1268b (bins 1.02) for QTL of H+, bnlg1268a-umc1290a (bins 1.09) for QTL of AP (acid phosphatase activity), dupssr15- P1M7/a (bins 6.06) for QTLs of PU (phosphorus uptake) and RW (root weight), and P1M3/d-P1M3/g (bins9.04) for QTLs of PU and AP. These QTLs are non-environment or minor QTLs × environment. By epistatic analysis, three main QTLs and eighteen QTLs × QTLs interactions were detected for the seven measured characteristics. These QTLs may affect trait expression by epistatic interaction with the other loci, and make a substantial contribution to phosphorus utilization efficiency, which should be considered when breeding maize varieties with high P efficiency. Two regions were detected in dupssr15- P1M7/a (bins 6.06) for QTL of RW and P1M3/d- P1M3/g (bins 9.04) for QTL of PU and AP. They were detected in two different environments and by two methods of QTL analysis, which were useful for marker-assisted selection. [ABSTRACT FROM AUTHOR]