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Introduction: The contamination of Trichoderma species causing green mold in substrates poses a significant obstacle to the global production of Lentinula edodes, adversely impacting both yield and quality of fruiting bodies. However, the diversity of Trichoderma species in the contaminated substrates of L. edodes (CSL) in China is not clear. The purpose of this study was to assess the biodiversity of Trichoderma species in CSL, and their interactions with L. edodes. Methods: A comprehensive two-year investigation of the biodiversity of Trichoderma species in CSL was conducted with 150 samples collected from four provinces of China. Trichoderma strains were isolated and identified based on integrated studies of phenotypic and molecular data. Resistance of L. edodes to the dominant Trichoderma species was evaluated in dual culture in vitro. Results: A total of 90 isolates were obtained and identified as 14 different Trichoderma species, including six new species named as Trichoderma caespitosus, T. macrochlamydospora, T. notatum, T. pingquanense, T. subvermifimicola, and T. tongzhouense, among which, T. atroviride, T. macrochlamydospora and T. subvermifimicola were identified as dominant species in the CSL. Meanwhile, three known species, namely, T. auriculariae, T. paraviridescens and T. subviride were isolated from CSL for the first time in the world, and T. paratroviride was firstly reported to be associated with L. edodes in China. Notebly, the in vitro evaluation of L. edodes resistance to dominant Trichoderma species showed strains of L. edodes generally possess poor resistance to Trichoderma contamination with L. edodes strain SX8 relatively higher resistant. Discussion: This study systematically investigated the diversity of Trichoderma species in the contaminated substrate of L. edodes, and a total of 31 species so far have been reported, indicating that green mold contaminated substrates of edible fungi were undoubtedly a biodiversity hotspot of Trichoderma species. Results in this study will provide deeper insight into the genus Trichoderma and lay a strong foundation for scientific management of the Trichoderma contamination in L. edodes cultivation. [ABSTRACT FROM AUTHOR]

The excessive use of cultivated land for non-grain production activities is considered a threat to grain security. This study presents an analysis framework on unraveling the causal mechanisms for non-grain production of cultivated land. We apply the analysis framework in Liyang, which is located in the Yangtze River Delta and is also an important "national grain base" county of China. We first determine four non-grain production categories as immediately recoverable (IMR), simple-engineering recoverable (SER), engineering recoverable (ENR), and irrecoverable (IR) based on the effect of non-grain activities on the degree of soil damage of the cultivated land, especially the difficulty of restoring the capacity for grain production. Then, we analyze the spatial pattern features for non-grain production of four given categories at the village scale. Furthermore, we reveal the mechanisms of the four categories using multiple linear regression modeling with geophysical, demographic, economic, and policy variables. The results show that the total non-grain area of cultivated land in Liyang is 28,158.38 hectares, and the non-grain rate is 48.09%, ranging from 10.59% to 96.75% among villages. The IMR, SER, ER, and IR rates are 11.81%, 17.76%, 15.07%, and 3.45%, respectively. There is also a significant neighborhood effect among the four categories, indicating that non-grain production activities have a stimulating effect on the surrounding operators of cultivated land. Farming conditions such as the proportion of irrigated farmland and economic variables such as the tourism scale have stronger effects on non-grain production than demographic variables. Policy variables, especially the cultivated land transfer policy, neither inhibit nor promote non-grain production. Based on these findings, we make policy suggestions for reducing non-grain production activities and protecting cultivated land. This analysis framework contributes to a new perspective for unraveling the causal mechanisms and making categorical governance decisions of non-grain production on cultivated land at the village level. [ABSTRACT FROM AUTHOR]

Planned urban form has become an important strategy to improve air quality in urban agglomerations (UAs), especially pollution due to PM 2.5 , but the influencing mechanisms are not yet clear. This study explores the relationship between four metrics of urban form (size, fragmentation, shape, and dispersion) as determined by analysis of remotely sensed images at 30-m resolution and PM 2.5 concentrations in 19 Chinese UAs. The influence of level of urban development and season is examined. Five control variables, including population density, temperature, precipitation, wind speed, and the normalized difference vegetation index (NDVI) are selected for use in multiple linear regression models. Size, fragmentation, and shape of urban form, but not dispersion, were found to have significant effects on PM 2.5 concentrations of different urbanization-level UAs. Urban size and fragmentation have stronger impacts on PM 2.5 concentrations in UAs with lower urbanization levels while urban shape has a greater impact in higher-level UAs. In terms of seasonal variation in all UAs, urban form is more pronouncedly associated with PM 2.5 concentrations during spring and autumn than summer and winter. Urban size and fragmentation are positively associated with PM 2.5 concentrations whereas urban shape and dispersion are on the contrary. The relationships between urban form and PM 2.5 uncovered here underscore the importance of urban planning as a tool to minimize PM 2.5 pollution. Specifically, local government should encourage polycentric urban form with lower fragmentation in urban agglomerations. UAs with lower urbanization levels should control the disordered expansion of construction land and higher-level UAs should promote the mix of green land and construction land. Moreover, measures to control air pollution from anthropogenic activities in spring, autumn and winter are likely to be more effective in decreasing PM 2.5 concentrations in UAs. • The urban form was measured by urban size, fragmentation, shape, and dispersion. • Effect of urban form on PM 2.5 concentrations varies with urbanization levels of urban agglomerations. • Seasonally, urban form has a stronger effect on PM 2.5 concentrations in spring and autumn. • Polycentric urban form with lower fragmentation should be encouraged in urban agglomerations for reducing PM 2.5 pollution. [ABSTRACT FROM AUTHOR]