BACKGROUND:Numerous quantitative trait loci (QTLs) and candidate genes associated with yield-related traits have been identified in cotton by genome-wide association study (GWAS) analysis. However, most of the phenotypic data were from a single or few environments, and the stable loci remained to be validated under multiple field environments.RESULTS:Here, 242 upland cotton accessions collected from different origins were continuously investigated for phenotypic data of four main yield components, including boll weight (BW) and lint percentage (LP) under 13 field environments, and boll number per plant (BN) and seed index (SI) under 11 environments. Correlation analysis revealed a positive correlation between BN and LP, BW and SI, while SI had a negative correlation with LP and BN. Genetic analysis indicated that LP had the highest heritability estimates of 94.97%, followed by 92.08% for SI, 86.09% for BW, and 72.92% for BN, indicating LP and SI were more suitable traits for genetic improvement. Based on 56,010 high-quality single nucleotide polymorphisms (SNPs) and GWAS analysis, a total of 95 non-redundant QTLs were identified, including 12 of BN, 23 of BW, 45 of LP, and 33 of SI, respectively. Of them, 10 pairs of homologous QTLs were detected between A and D sub-genomes. We also found that 15 co-located QTLs with more than two traits and 12 high-confidence QTLs were detected under more than six environments, respectively. Further, two NET genes (GH_A08G0716 and GH_A08G0783), located in a novel QTL hotspot (qtl24, qtl25 and qlt26) were predominately expressed in early fiber development stages, exhibited significant correlation with LP and SI. The GH_A07G1389 in the stable qtl19 region encoded a tetratricopeptide repeat (TPR)-like superfamily protein and was a homologous gene involved in short fiber mutant ligon lintless-y (Liy), implying important roles in cotton yield.CONCLUSIONS:The present study provides a foundation for understanding the regulatory mechanisms of yield components and may enhance yield improvement through molecular breeding in cotton.

Succinate dehydrogenase (SDH) is demonstrably one of the most important molecular targets in development of new fungicide. In our continuous efforts to discover novel SDH inhibitors, forty-two carboxamide derivatives containing 1,2,3-triazole ring were designed and synthesized, which were precisely characterized by 1H NMR, ESI-MS, elemental analysis and X-ray single-crystal diffraction. The compounds were screened for antifungal activities against phytopathogenic fungi by mycelia growth inhibition assay in vitro. Compound A3-3 exhibited significant antifungal activity against Sclerotinia sclerotiorum, Botrytis cinerea, Rhizoctonia cerealis and Gaeumannomyces graminsis with EC50 values of 1.08, 8.75, 1.67 and 5.30 μg/mL, respectively, comparable to those of commercial SDHI boscalid. In vivo testing demonstrated that A3-3 was effective for suppressing rape sclerotinia rot, cucumber grey mould and wheat powdery mildew caused by S. sclerotiorum， B. cinerea and Blumeria graminis at a dosage of 200 μg/mL. Inhibition activities against SDH test proved the designed analogues were effective in the enzyme level. The molecular docking simulation revealed that A3-3 interacted with ARG43，TYR58 and TRP173 of the SDH through hydrogen bond and pi-pi interaction, which could explain the probable mechanism of action between the inhibitor and target protein.

Ubiquitous natural organic matter (NOM) plays a crucial role in the peroxidase-mediated transformation of phenolic pollutants in aquatic environment. As a poorly defined polydispersed mixture of assorted organic substances with wide molecular weight (MW) distribution, NOM has far prevented researchers from finding out the primarily responsible components for the specific effect. In this work, MW fractionated NOMs (Mf-NOMs) were used to investigate their roles on horseradish peroxidase (HRP)-mediated transformation of 17α-ethinylestradiol (EE2). The removal rate of EE2 was restrained in the presence of pristine or Mf-NOMs, and the inhibitory mechanism was MW-dependent. Low Mf-NOMs restrained the enzymatic reaction by acting as competitive substrates, while high Mf-NOMs retained freely dissolved EE2 which reduced its availability for enzymatic reaction. The contribution of these two processes to the inhibition induced by pristine NOM was further quantified and found to be relevant to the reaction conditions, especially EE2 concentration. The findings of this work reveal more complex influences of NOM on the enzymatic reaction than ever demonstrated, which aids in understanding the fate of EE2 and other congener contaminants in natural and municipal water.

A series of benzimidazole phenylhydrazone derivatives (6a–6ai) were synthesized and characterized by 1H-NMR, ESI-MS, and elemental analysis. The structure of 6b was further confirmed by single crystal X-ray diffraction as (E)-configuration. All the compounds were screened for antifungal activity against Rhizoctonia solani and Magnaporthe oryzae employing a mycelium growth rate method. Compound 6f exhibited significant inhibitory activity against R. solani and M. oryzae with the EC50 values of 1.20 and 1.85 μg/mL, respectively. In vivo testing demonstrated that 6f could effectively control the development of rice sheath blight (RSB) and rice blast (RB) caused by the above two phytopathogens. This work indicated that the compound 6f with a benzimidazole phenylhydrazone scaffold could be considered as a leading structure for the development of novel fungicides.

A series of new 1,2,3-triazole derivatives have been prepared and screened for their antifungal activity against phytopathogenic fungi using the mycelium growth inhibition method in vitro. The results indicated that the 1,2,3-triazole hydrazide scaffold displayed significant antifungal activity. Compound 6ad exhibited the most potent anti-phytopathogenic activity, with EC50 values of 0.18, 0.35, 0.37 and 2.25 mu g mL(-1) against Rhizoctonia solani, Sclerotinia sclerotiorum, Fusarium graminearum, and Magnaporthe oryzae, respectively. In vivo testing demonstrated that 6ad was effective for the control of rice sheath blight, rape sclerotinia rot, fusarium head blight and rice blast caused by the aforementioned phytopathogens. This work suggests that the combination of 1,2,3-triazole and hydrazide moiety could be a promising fungicide scaffold in the future. (C) 2016 Elsevier Masson SAS. All rights reserved.