Alternaria solani effectors AsCEP19 and AsCEP20 reveal novel functions in pathogenicity and conidiogenesis.

Previous work identified a pair of specific effectors AsCEP19 and AsCEP20 in Alternaria solani as contributors to the virulence of A. solani. Here, we constructed AsCEP19 and AsCEP20 deletion mutants in A. solani strain HWC168 to further reveal the effects of these genes on the biology and pathogenicity of A. solani. Deletion of AsCEP19 and AsCEP20 did not affect vegetative growth but did affect conidial maturation, with an increase in the percentage of abnormal conidia produced. Furthermore, we determined the expression patterns of genes involved in the conidiogenesis pathway and found that the regulatory gene abaA was significantly upregulated and chsA, a positive regulator for conidiation, was significantly downregulated in the mutant strains compared to the wild-type strain. These results suggest that AsCEP19 and AsCEP20 indirectly affect the conidial development and maturation of A. solani. Pathogenicity assays revealed significantly impaired virulence of ΔAsCEP19, ΔAsCEP20, and ΔAsCEP19 + AsCEP20 mutants on potato and tomato plants. Moreover, we performed localization assays with green fluorescent protein-tagged proteins in chili pepper leaves. We found that AsCEP19 can specifically localize to the chloroplasts of chili pepper epidermal cells, while AsCEP20 can localize to both chloroplasts and the plasma membrane. Weighted gene co-expression network analysis revealed enrichment of genes of this module in the photosynthesis pathway, with many hub genes associated with chloroplast structure and photosynthesis. These results suggest that chloroplasts are the targets for AsCEP19 and AsCEP20. IMPORTANCE: Alternaria solani is an important necrotrophic pathogen causing potato early blight. Previous studies have provide preliminary evidence that specific effectors AsCEP19 and AsCEP20 contribute to virulence, but their respective functions, localization, and pathogenic mechanisms during the infection process of A. solani remain unclear. Here, we have systematically studied the specific effectors AsCEP19 and AsCEP20 for the first time, which are essential for conidial maturation. The deletion of AsCEP19 and AsCEP20 can significantly impair fungal pathogenicity. Additionally, we preliminarily revealed that AsCEP19 and AsCEP20 target the chloroplasts of host cells. Our findings further enhance our understanding of the molecular mechanisms underlying the virulence of necrotrophic pathogens.

[Synergistic Paths of Reduced Pollution and Carbon Emissions Based on Different Power Demands in China].

Nowadays, China is faced with two strategic tasks:improving ecological environmental quality and realizing carbon neutrality and carbon peaking. Synergy to reduce pollution and carbon emissions has become an inevitable choice for the comprehensive green transition of economic and social development in China. The electric power sector will play an important role in the transition process. Based on different power demand scenarios, a multi-objective model was constructed to achieve carbon peaking and carbon neutrality at a low cost, and the optimal path scheme of carbon emission reduction synergy was obtained. The results showed that under the premise of achieving carbon peaking and carbon neutrality as scheduled, pollution reduction and carbon reduction had good synergies, and their synergistic control could effectively facilitate the realization of the low-carbon transition. Optimizing the power generation structure of the electric power sector was the key measure to achieving the synergistic effect of pollution reduction and carbon reduction. During the study period, the proportion of thermal power decreased continuously, and the proportion of clean power exceeded 92.5%. The emissions of carbon dioxide and major air pollutants were significantly different under different power demands. Carbon dioxide emissions were most affected by power demand. The peak carbon dioxide emissions under low power demand, medium power demand, and high power demand were 9.416 billion, 10.409 billion, and 10.746 billion t, respectively. The emissions of sulfur dioxide, nitrogen oxide, and particulate matter also showed an increasing trend in the low power demand, medium power demand, and high power demand scenarios. The increase in power demand only increased the pressure of power generation structure adjustment within the electric power sector, without affecting the output and activity level of other sectors, that is, the pressure of emission reduction in the electric power sector caused by power demand did not show the trend of transmission between sectors.

[Evaluation Method and Application for Urban Carbon Peaking & Neutrality Performance].

As the key unit of greenhouse gas emission sources, cities have the most direct and fundamental significance to achieve the national carbon peaking carbon neutrality goal. In order to evaluate the current performance of urban carbon peaking and neutrality, a set of urban peaking and carbon neutrality action index evaluation systems consisting of three criterion layers, seven elements, and fourteen specific index layers were developed based on the analytic hierarchy process considering the preferences of decision makers, through the steps of influencing factor determination, indicator selection, and scoring principle determination, as well the indicator weightings. Thus, a relatively comprehensive scientific evaluation method was formed to fully evaluate the attitude of the government towards the goal of carbon peaking and neutrality, the state of social economy, energy consumption, industrial structure, transportation, and other aspects, as well as the actual effect of emission reduction efficiency and trends. Through the central city evaluation application study, it was found that the first-tier economically developed and low-carbon pilot cities had a more outstanding comprehensive performance in reaching the peak and neutrality. The comprehensive scores of Beijing, Shenzhen, Wuhan, Shanghai, Qingdao, Guangzhou, Chengdu, Xiamen, Kunming, and Lanzhou all exceeded 60 points. Beijing, Xiamen, Ningbo, Shenzhen, and Qingdao had significant climate ambitions, whereas Haikou, Guangzhou, Chengdu, Nanning, and Beijing had a better low-carbon status. Kunming, Lanzhou, Luoyang, Daqing, Jilin, and other cities showed significant emission reduction trends. Most cities still had problems such as insufficient willingness to reach the peak and lack of statistical information disclosure system. The evaluation method could be optimized by improving the index system, updating the empowerment, and forming the annual evaluation mechanism next step. It is suggested to formulate the local carbon reduction work plan by coordinating the whole country at different levels, improve the urban energy and greenhouse gas statistics and information disclosure system, and organize the carbon peaking pilot construction in areas where conditions permit.

[Pollution and Carbon Reduction Effect of OFDI in China and Its Mechanism].

Under the "Going out" strategy and the Belt and Road Initiatives, the trade in goods and services and flow of production factors between China and the rest of the world have become more frequent, and the total amount of outward foreign direct investment (OFDI) is considerable and growing significantly. Therefore, along with the extensive economic growth and the substantial growth of foreign investment, the environmental impact of OFDI has become noteworthy. Here, through theoretical analysis and logical deduction, three possible pathways of the impact of OFDI in China on the environment were presented as hypotheses, which included the industrial structure, the technological innovation progress, and the economic-scale expansion. Using Chinese provincial data from 2004 to 2019, an environmental load index including main environmental pollutant emissions and carbon emissions was constructed. Taking this as the dependent variable, an intermediary effect method was constructed to analyze the home pollution and carbon reduction effect and the influence mechanism of OFDI in China. The results showed that ① OFDI in China reduced the environmental load, and each 1% increase in OFDI reduced the environmental load by 0.051%-0.076%. ② The OFDI in China reduced the environmental load by advancing the industrial structure and technological innovation progress, and a 1% increase in OFDI resulted in a 0.060% and 0.006% reduction in environmental load through their indirect effects, respectively, whereas OFDI increased the environmental load by 0.009% through the path of economic-scale expansion. The contributions of leading environmental load changes mediated by advancing industrial structure, technological innovation progress, and economic-scale expansion were 65.9%-84.5%, 6.6%-8.5%, and -12.7%- -9.9%, respectively, and the contribution of OFDI directly driving the environmental load to change was 19.7%-37.4%. Based on this, policy recommendations, including promoting Chinese enterprises and capital going abroad, encouraging relatively disadvantaged domestic industries to explore foreign markets, strengthening reverse technology spillover effects, and forming a sustainable low-carbon development mode, have been proposed.

A comparative study of stage characteristics and factorial decomposition of CO2 emissions between China and the USA.

CO2 contributes a lot to the greenhouse effect. The total CO2 emissions of the two countries, China and the USA, as the world's top two economies, have exceeded 40% of the total global carbon emissions. In this context, the exploration of the evolution of carbon emissions from energy consumption in China and the USA and the comparison of the characteristics of carbon emission drivers in different periods play a significant role in the policy formulation and climate change cooperation between China and the USA. In this study, the BP structural breakpoint test was used to divide the carbon emission stages of China and the USA from 1970 to 2019. The generalized Divisia index model (GDIM) was developed to decompose the growth of carbon emissions in China and the USA into eight items, GDP, carbon intensity of GDP, energy use, carbon intensity of energy, population, carbon emissions per capita, GDP per capita, and energy intensity, and to analyze the characteristics and cumulative contribution of carbon emission drivers at each stage. Based on the stage and cumulative characteristics of carbon emissions between China and the USA, the USA should take the initiative to assume the legal responsibility of carbon emissions and further deepen the cooperation with other countries in the field of climate change. China should transform the economic growth mode, optimize the energy structure, and improve the efficiency of resource utilization to help achieve the peaking carbon emissions and the carbon neutrality smoothly.