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Land use change drives the ecosystem service value (ESV) to some extent. Investigating the impact of land use distribution patterns under different scenarios on ESV is crucial for optimizing land spatial utilization in tropical island regions. This study employs a combination of multi-objective programming (MOP) and the patch-generating land use simulation (PLUS) model to simulate and predict the spatial distribution of land use in Hainan Island for the year 2030 under three scenarios: natural development, ecological protection priority, and tourism development priority. The ESV for these scenarios is then assessed to provide insights into the sustainable economic, social, and ecological development of tropical island regions. The results indicate the following: (1) Between 2010 and 2020, forest land was the dominant land use type in Hainan Island, accounting for 63% of the total area, followed by arable land. Land use changes were characterized mainly by increases in built-up land and grass land, which increased by 497.13 km2 and 18.87 km2, respectively, with decreases in other types. The largest area of land conversion was from forest land, which was predominantly converted to built-up land and arable land, measuring 259.97 km2 and 174.49 km2, respectively. (2) The PLUS model was used to simulate land use changes in Hainan Island, achieving a Kappa coefficient of 0.88 and an overall accuracy of 0.94, indicating a high consistency between the simulation results and actual data. (3) The ecological protection priority scenario yielded the highest ecosystem service values (CNY 72.052 billion), while the values under other scenarios decreased compared to 2020. The natural development scenario saw a decrease of CNY 1.821 billion, and the tourism development priority scenario saw a decrease of CNY 0.595 billion. Spatially, the ecological protection priority scenario also showed the greatest increase in areas with high ecosystem service values, particularly due to an increase in forest land area, which contributed to an overall increase in the ecosystem service values of the study area. This study offers a scientific foundation and a decision-making reference for selecting priority scenarios for tourism development on Hainan Island, aimed at supporting its future sustainable development. It emphasizes the protection of forest resources, the promotion of greening initiatives, and the achievement of a balance between ecological preservation and tourism activities. [ABSTRACT FROM AUTHOR]

Arthrobotrys oligospora is a typical nematode-trapping (NT) fungus, which can secrete food cues to lure, capture, and digest nematodes by triggering the production of adhesive networks (traps). Based on genomic and proteomic analyses, multiple pathogenic genes and proteins involved in trap formation have been characterized; however, there are numerous uncharacterized genes that play important roles in trap formation. The functional studies of these unknown genes are helpful in systematically elucidating the complex interactions between A. oligospora and nematode hosts. In this study, we screened the gene AOL_s00004g24 (Ao4g24). This gene is similar to the SWI/SNF chromatin remodeling complex, which was found to play a potential role in trap formation in our previous transcriptome analysis. Here, we characterized the function of Ao4g24 by gene disruption, phenotypic analysis, and metabolomics. The deletion of Ao4g24 led to a remarkable decrease in conidia yield, trap formation, and secondary metabolites. Meanwhile, the absence of Ao4g24 influenced the mitochondrial membrane potential, ATP content, autophagy, ROS level, and stress response. These results indicate that Ao4g24 has crucial functions in sporulation, trap formation, and pathogenicity in NT fungi. Our study provides a reference for understanding the role of unidentified genes in mycelium growth and trap formation in NT fungi. [ABSTRACT FROM AUTHOR]

Prdx2 is a peroxiredoxin (Prx) family protein that protects cells from attack via reactive oxygen species (ROS), and it has an important role in improving the resistance and scavenging capacity of ROS in fungi. Arthrobotrys oligospora is a widespread nematode-trapping fungus that can produce three-dimensional nets to capture and kill nematodes. In this study, AoPrdx2, a homologous protein of Prx5, was investigated in A. oligospora via gene disruption, phenotypic analysis, and metabolomics. The deletion of Aoprdx2 resulted in an increase in the number of mycelial septa and a reduction in the number of nuclei and spore yield. Meanwhile, the absence of Aoprdx2 increased sensitivity to oxidative stresses, whereas the ∆Aoprdx2 mutant strain resulted in higher ROS levels than that of the wild-type (WT) strain. In particular, the inactivation of Aoprdx2 severely influenced trap formation and pathogenicity; the number of traps produced by the ∆Aoprdx2 mutant strain was remarkably reduced and the number of mycelial rings of traps in the ∆Aoprdx2 mutant strain was less than that of the WT strain. In addition, the abundance of metabolites in the ∆Aoprdx2 mutant strain was significantly downregulated compared with the WT strain. These results indicate that AoPrdx2 plays an indispensable role in the scavenging of ROS, trap morphogenesis, and secondary metabolism. [ABSTRACT FROM AUTHOR]