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Tilia is a complex genus in the family Malvaceae that has high ecological and economical values. Owing to the lack of sufficient distinguishable morphological and molecular characteristics, interspecific relationships in this genus are not clear. Chloroplast (cp) genomes are small, meanwhile most angiosperms usually undergo matrilineal inheritance. Consequently, they can be used in molecular systematics and phylogenetic analyses. Here, we sequenced and assembled cp genomes from T. endochrysea, T. tomentosa, T. miqueliana, T. americana and T. cordata, and compared them with those of seven previously reported Tilia species. Similar gene contents, gene orders and GC contents existed among the 12 cp genomes, which ranged from 162,564 to 162,855 bp and encoded 113 unique genes. Abundant simple sequence repeats (119–127) and dispersed repeats (97–135) were detected in Tilia cp genomes. In total, 11 hypervariable regions were identified that could be suitable for species identification and phylogenetic studies. A phylogenetic analysis of Malvaceae based on 5 hypervariable genes (matK + ndhF + rpoB + rpoC2+ycf1) revealed that all eight subfamilies were monophyletic groups. Additionally, the genus Tilia was divided into three groups on the basis of all 521 molecular variation loci. The current study provides valuable insights into the genomic evolution of the genus Tilia.

Microplastics and nanoplastics (MPs/NPs) are posing emerging potential threats to global ecosystems and human health. Recently, the individual effects of MPs/NPs and combined effects of MPs/NPs-coexisting pollutants on soil–terrestrial plant systems have attracted increasing attention. Based on the latest research progress, this review firstly summarized the sources of MPs/NPs and the interaction between MPs/NPs and coexisting pollutants in soil environment, and then systematically induced their multilevel impacts on soil properties and terrestrial plants. Soil and agroecosystem are major long-term sinks of primary and secondary MPs/NPs, with extensive sources. MPs/NPs exhibit universal adsorption capacities and can further serve as the vectors for varied heavy metal, organic and biological contaminants. Generally, MPs/NPs and the combination with coexisting contaminants may affect soil physical, chemical and microbiological properties, soil structure and functions, while the specific impacts and degree depend on MP/NP characteristics including polymer type, size, shape, concentration and degradability. Increasing evidence confirmed the uptake and translocation of MPs/NPs in terrestrial plants and proved their influence on growth performance, metabolism and physiological toxicity, as well as cytotoxicity and genotoxicity. The specific effects vary as a function of MP/NPs properties, plant species and environmental conditions. The joint effects of MPs/NPs and coexisting pollutants are complex, and synergistic, antagonism and neutralization effects have been reported at different circumstances. Further comprehensive and in-depth studies are urgently needed to fulfill the current knowledge gaps, especially the deficiency in the inherent mechanisms.

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