Wide Distribution of Teratosphaeria epicoccoides and T. destructans Associated with Diseased Eucalyptus Leaves in Plantations in Southern China.

Species of Mycosphaerellaceae and Teratosphaeriaceae represent over 40% of the fungi identified on eucalypt leaves worldwide. These include some important pathogens that mainly cause leaf blight and spot, and result in increasingly negative impacts on global commercial eucalypt industries. Eucalyptus plantations are commonly cultivated in southern China for solid wood and pulp products. However, the species diversity and geographic distribution of Mycosphaerellaceae and Teratosphaeriaceae, associated with diseased plantation Eucalyptus leaves in China, have not been clarified. In this study, we conducted the first systematic surveys and sample collections of Mycosphaerellaceae- and Teratosphaeriaceae-like fungi from diseased plantation Eucalyptus leaves in southern China. In total, 558 isolates were obtained from 59 sampled sites in five provinces. One isolate was isolated from each tree. According to the disease symptoms, conidia morphological characteristics, and DNA sequence comparisons of ITS, tef1 and tub2 gene regions. The 558 isolates were identified as Teratosphaeria epicoccoides (312 isolates; 55.9%) and T. destructans (246 isolates, 44.1%). Both species were widely distributed in the sampled regions in southern China. The genotypes of T. epicoccoides and T. destructans were determined based on ITS, tef1, and tub2 sequences. The results showed that multiple genotypes of each species of T. epicoccoides and T. destructans exist in China. Additionally, isolates with multiple genotypes were obtained in all five sampled provinces. These results suggest that both T. epicoccoides and T. destructans are not clonal. This study proved that both T. epicoccoides and T. destructans are dominant species and widely distributed on diseased Eucalyptus leaves in southern China. The wide geographic distribution and potential high genetic diversity pose challenges for the disease management of Teratosphaeria leaf blight and leaf spot in China.

Quantified the influence of different synoptic weather patterns on the transport and local production processes of O3 events in Pearl River Delta, China.

Regional ozone (O3) pollution in the Pearl River Delta (PRD) region has become a topic of discussion in recent years. The occurrence of regional O3 pollution are influenced by local emissions and cross-regional transportation. In this study, we identified the predominant synoptic patterns that were associated with regional O3 pollution from August to November in 2015-2021 using the Lamb-Jenkinson classification technique. All synoptic types were divided into four major categories of NE-type, C-type, S-type and A-type, which accounted for 42 %, 25 %, 18 % and 15 % of the total number of regional O3 pollution days, respectively. The weather conditions for each synoptic pattern were described by using MERRA-2 datasets. Then a rapidly method was established to quantify the contribution of cross-regional processes to high O3 concentration in different synoptic patterns over the PRD through the WRF-Flexpart model. The NE-type weather condition was characterized by a relatively large wind speed with a significant cross-regional transport contribution of 35.8 %. The A-type weather condition had moderate surface wind speed with the stable weather condition, resulting in a lower cross-region transport contribution of 27.7 %. Under controlled by C-type, the stagnant weather condition caused by low-pressure systems on its periphery, would suppress diffusion of O3. As a result, the regional O3 pollution in the PRD were mostly attributed to locally (87.9 %) with minimal cross-regional transport (12.1 %). The S-type weather condition was mainly associated with the West Pacific Subtropical High and the surface equalization pressure field, accompanied by low wind speed. Therefore, the considerable (minor) contribution of local production (cross-regional transport) of 83.3 % (16.7 %) to O3 pollution in the PRD is a consequence of the stagnation weather condition.

[Impact of Accelerated Electrification Under the Low Carbon Path in Dongguan City on the Coordinated Emission Reduction of CO2 and Pollutants].

Cities are the center of energy consumption. Electrification integrates urban energy structure and achieves the efficient use of clean energy. Exploring the urban impact of accelerated electrification under the low-carbon path is crucial to reducing urban pollution and carbon. Based on the Long-range Energy Alternative Planning System(LEAP-DG), this study set up three scenarios, including the baseline, low-carbon, and accelerated electrification scenarios, to evaluate the emission reduction potential of electrification under different power structures, quantify the contribution of key sectors, and discuss the coordinated emission reduction effect of Dongguan, a typical manufacturing city in Guangdong. The results showed that accelerated electrification under the low-carbon path would reduce the emission intensity of power pollutants, and in 2050, Dongguan will further reduce CO2, NOx, VOC, and CO by 7.35×106, 1.28×104, 1.62×104, and 8.13×104 t; SO2 and PM2.5 emission reductions on the consumption side and increased emissions on the production side had been balanced. Accelerated electrification in the industrial and transportation sectors would reduce CO2 and air pollutant emissions at the same time, and the transportation sector would benefit from the high conversion efficiency of fuel vehicles and electric vehicles, reducing CO2, CO, VOC, and NOx by 5.42×106, 7.76×104, 1.43×104, and 1.06×104 t, respectively, in 2050. In the building sector with high electrification rates, coal power was higher in extra electricity, increasing CO2 and pollutant emissions. Under the optimization of power supply structure, cities can reasonably adjust the electrification of different departments to achieve targeted pollution prevention and control.

Characterization of Pseudofusicoccum Species from Diseased Plantation-Grown Acacia mangium, Eucalyptus spp., and Pinus massoniana in Southern China.

Fungi from Pseudofusicoccum (Phyllostictaceae, Botryosphaeriales) have been reported as pathogens, endophytes, or saprophytes from various woody plants in different countries. Recently, Botryosphaeriales isolates were obtained from the dead twigs of Acacia mangium, Eucalyptus spp., Pinus massoniana, and Cunninghamia lanceolata in Guangdong, Guangxi, Hainan, and Fujian Provinces in southern China. This study aimed to understand the diversity, distribution, and virulence of these Pseudofusicoccum species on these trees. A total of 126 Pseudofusicoccum isolates were obtained, and the incidences of Pseudofusicoccum (percentage of trees that yielded Pseudofusicoccum) on A. mangium, P. massoniana, Eucalyptus spp., and C. lanceolata were 21%, 2.6%, 0.5%, and 0%, respectively. Based on the internal transcribed spacer (ITS), translation elongation factor 1-alpha (tef1), and ß-tubulin (tub2) loci, 75% of the total isolates were identified as P. kimberleyense, and the remaining isolates were identified as P. violaceum. For P. kimberleyense, the majority of isolates (83%) were from A. mangium, and the rest were from P. massoniana (14%) and Eucalyptus spp. (3%). Similarly, the proportion of isolates of P. violaceum from A. mangium, P. massoniana, and Eucalyptus spp. were 84%, 13%, and 3%, respectively. Inoculation trials showed that the two species produced expected lesions on the tested seedlings of A. mangium, E. urophylla × E. grandis, and P. elliottii. This study provides fundamental information on Pseudofusicoccum associated with diseases in main plantations in southern China.