Temporal and spatial variations of soil C, N contents and C:N stoichiometry in the major grain-producing region of the North China Plain.

Soil C, N contents and C:N stoichiometry are important indicators of soil quality, the variation characteristics of which have great significance for soil carbon-nitrogen cycle and sustainable utilization. Based on 597 observations along with soil profiles of 0-20cm depth in the 1980s and the 2010s, the temporal and spatial variations of soil C, N contents and C:N stoichiometry in the major grain-producing region of the North China Plain were illustrated. Results showed that there were significant changes in soil C, N contents over time, with increasing rates of 60.47% and 50%, respectively. The changes of C, N contents resulting in a general improvement of C:N stoichiometry. There was a significant decline in nugget effects of soil C, N contents from the 1980s to 2010s, the spatial autocorrelation of soil nutrients showed an increasing trend, and the effect of random variation was reduced. C:N stoichiometry was higher in Huixian City and Weihui City, and lower in Yanjin County, an apparent decline was observed in the spatial difference of soil C:N stoichiometry from the 1980s to 2010s. Soil C, N contents and C:N stoichiometry differed among soil types, agricultural land-use types, and topography in space. The temperature, precipitation, and fertilization structure were considered as the main factors that induce the temporal variations. These findings indicated that the soil nutrient elements in the farmland ecosystems changed in varying degrees in both time and space scales, and the variation was influenced by soil types, land-use types, topography, meteorological factors, and fertilization structure.

The Enhancement of Antiviral Activity of Chloroinconazide by Aglinate-based Nanogel and Its Plant Growth Promotion Effect.

Improving the efficiency and prolonging the duration of pesticides are of great significance in agricultural production. In this work, based on the antiviral compound chloroinconazide (CHI) synthesized previously, the improvement of the fabricated CHI-loaded alginate-based nanogel (CHI@ALGNP) was studied. It was found that CHI@ALGNP showed higher foliar adhesion than CHI and exhibited a sustained release for up to 7 days. CHI@ALGNP could also continuously activate the reactive oxygen species and antioxidant levels and induce the increase of salicylic acid content and the expression of its responsive gene PR2 for a long time, thus achieving sustained resistance to tobacco mosaic virus infection in Nicotiana benthamiana. Strikingly, CHI@ALGNP could release Ca2+ and Mg2+ to promote the growth of N. benthamiana. Taken together, for the first time, we have shown the improvement of a nanogel carrier to the antiviral activity and growth promotion of small molecular pesticides. As the alginate-based nanogel can be easily applied to the spray-based pesticide delivery technology, our study provides a new strategy for the development of new pesticide preparations and the application of multifunctional pesticides.

Synthetic chloroinconazide compound exhibits highly efficient antiviral activity against tobacco mosaic virus.

BACKGROUND: Development of anti-plant-virus compounds and improvement of biosafety remain hot research topics in controlling plant viral disease. Tobacco mosaic virus (TMV) infects all tobacco species as well as many other plants worldwide and causes severe losses in tobacco production. To date, no efficient chemical treatments are known to protect plants from virus infection. Therefore, the search for a highly active antiviral compound with high efficacy in field application is required. RESULTS: We reported the synthesis of a novel antiviral halogenated acyl compound Chloroinconazide (CHI) using tryptophan as a substrate and examined its anti-TMV activity. We found that CHI displayed the ability to strongly inhibit the infection of TMV on Nicotiana benthamiana via multiple mechanisms. We observed that CHI was able to impair the virulence of TMV by directly altering the morphological structure of virions and increasing the activity of anti-oxidative enzymes, resulting in reduced TMV-induced ROS production during infection of the plant. In addition, the expression of salicylic acid-responsive genes was significantly increased after CHI application. However, after application of CHI on SA-deficient NahG plants no obvious anti-TMV activity was observed, suggesting that the SA signaling pathway was required for CHI-induced anti-TMV activity associated with reduced infection of TMV. CHI exhibited no effects on plant growth and development. CONCLUSION: The easily synthesized CHI can actively induce plant resistance against TMV as well as act on virus particles and exhibits high biosafety, which provides a potential for commercial application of CHI in controlling plant virus disease in the future. © 2020 Society of Chemical Industry.