The successful establishment of invasive populations is closely linked to environmental factors. It is unclear whether coexisting species in the native area follow the same genetic pattern in the invaded continents under the local climate factors. Two coexisting morphologically similar snails (Pomacea canaliculata and P. maculata), native to tropical and sub-tropical South America, have become invasive species for agriculture production and wetland conservation across five continents over 40 years. We analyzed the correlation between the genetic diversity of the two snails and the climate factors or habitat changes. Based on the 962 sequences from the invaded continents and South America, the nucleotide diversity in the agricultural habitat was low for P. canaliculata, whereas it was high for P. maculata, compared with that in the non-agricultural habitat. The two snails showed a divided population structure among the five continents. The P. canaliculata population in the invaded continents has remained stable, whereas the P. maculata population expanded suddenly. Seven main haplotype networks and two ancestral haplotypes (Pc3, Pm1) were found in the P. canaliculata and P. maculata populations. The haplotypes of the two snails were related to local climate factors. The overall fixation index of P. canaliculata and P. maculata was 0.2657 and 0.3097 between the invaded continents and South America. The population expansion of the two snails fitted the isolation-by-distance model. We discovered nine new sequences from the sampling locations. Overall, the genetic diversity and genetic differentiation of the two invasive snails were closely related to geographic separation, agricultural habitat, and climate factors.

Rice is widely planted and serves as staple food in the world, but it is often exposed to acid rain and rice blast (Pyricularia oryzae). In this work, we analyzed the effects of co-exposure to simulated acid rain (SAR) and P. oryzae on the photosynthetic growth of rice seedlings. We found that the growth, photosynthesis, and chloroplast ultrastructure of rice seedlings were damaged under single treatments of P. oryzae and strong acid rain (pH 2.0) but increased under medium acidity acid rain (pH 4.0). Similarly, when plants were exposed to both P. oryzae and acid rain, pH 4.0 mitigated the changes of growth, photosynthetic characteristics, and chloroplast ultrastructure induced by P. oryzae, but pH 2.0 aggravated these changes. In addition, we found that significant differences in chlorophyll content (chlorophyll a and chlorophyll b) correlated with transpiration rate (Tr) under the combined stress of acid rain and P. oryzae at pH 4.0 and pH 2.0. Medium-acidity acid rain alleviated the harm caused by P. oryzae on rice growth by enhancing synergistic regulatory mechanisms of photosynthetic traits to increase plant resistance tolerance. The effect of P. oryzae on photosynthetic traits of rice was regulated by acidity of acid rain.

Prickly pear (Rosa roxburghii Tratt), a shrub mainly distributed in South China, is an economically essential plant for helping the local people out of poverty. To efficiently provide sufficient nutrients to the plant in the soil for the ecological cultivation of prickly pear, we studied the aerobic composting of a prickly pear litter with three agents, including AC (Bacillus natto, Bacillus sp., Actinomycetes sp., Saccharomyces sp., Trichoderma sp., Azotobacter sp., and Lactobacillus sp.), BC (Bacillus subtilis, Lactobacillaceae sp., Bacillus licheniformis, Saccharomyces sp., and Enterococcus faecalis), and CC (Bacillus sp., Actinomycetes sp., Lactobacillaceae sp., Saccharomyces sp., and Trichoderma sp.) and a control without microbial agents. The results show that the physicochemical and microbial traits of three resultant prickly pear composts were different after the inoculation with AC, BC, or CC. The pH values of three composts ranged from 8.0 to 8.5, and their conductivity values were between 1.6 and 1.9 mS/cm. The seed germination index of all three composts exceeded 70%. The contents of volatile solids and organic matter of the three composts both decreased significantly. The BC maximally increased the total N (18%) of the compost, whereas the CC maximally increased the total P (48%) and total K (38%) contents. Contents of available P and available K of the three composts increased significantly, and the available N content in compost after BC inoculation increased by 16%. The physicochemical features showed that three composts were non-hazardous to plants, and the microbial agents improved nutrient availability. The richness, Chao1, and Shannon index in the bacterial communities of three composts increased significantly. At the phylum level, Proteobacteria, Bacteroidetes, and Firmicutes bacterium became dominant in the three composts, whereas at the family level, Microscillaceae and A4b (phylum Chloroflexi) became the dominant groups. Abundant cellulose-degrading bacteria existed at the dominant phylum level, which promoted fiber degradation in composts. Organic matter and the available N content regulated the composting bacterium. The inoculants enhanced the efficiency of composting: agents B and C were more suitable exogenous inoculants for the composting of a prickly pear litter.