Heavy metal pollution of the soil affects the environment and human health. Masson pine is a good candidate for phytoremediation of heavy metal in mining areas. Microorganisms in the rhizosphere can help with the accumulation of heavy metal in host plants. However, studies on its rhizosphere bacterial communities under heavy metal pollution are still limited. Therefore, in this study, the chemical and bacterial characteristics of Masson pine rhizosphere under four different levels of heavy metal pollution were investigated using 16 S rRNA gene sequencing, soil chemistry and analysis of plant enzyme activities. The results showed that soil heavy metal content, plant oxidative stress and microbial diversity damage were lower the farther they were from the mine dump. The co-occurrence network relationship of slightly polluted soils (C1 and C2) was more complicated than that of highly polluted soils (C3 and C4). Relative abundance analysis indicated Sphingomonas and Pseudolabrys were more abundant in slightly polluted soils (C1 and C2), while Gaiella and Haliangium were more abundant in highly polluted soils (C3 and C4). LEfSe analysis indicated Burkholderiaceae, Xanthobacteraceae, Gemmatimonadaceae, Gaiellaceae were significantly enriched in C1 to C4 site, respectively. Mantel analysis showed that available cadmium (Cd) contents of soil was the most important factor influencing the bacterial community assembly. Correlation analysis showed that eight bacterial genus were significantly positively associated with soil available Cd content. To the best of our knowledge, this is the first study to investigate the rhizospheric bacterial community of Masson pine trees under different degrees of heavy metal contamination, which lays the foundation for beneficial bacteria-based phytoremediation using Masson pines in the future.

The EFSA Panel on Plant Health performed a pest categorisation of Dendrolimus punctatus (Lepidoptera: Lasiocampidae), following a commodity risk assessment of bonsai Pinus parviflora grafted onto P. thunbergii from China, in which D. punctatus was identified as a pest of possible concern to the European Union (EU). D. punctatus, also known as the Masson pine caterpillar, is present in China, Taiwan, Vietnam, India and has recently spread to Japanese islands close to Taiwan. Larval feeding on the needles of Pinus elliottii, P. luchuensis, P. massoniana, P. merkusii and P. tabulaeformis causes important damage. D. punctatus larvae can also feed on P. armandii, P. echinata, P. latteri, P. parviflora, P. sylvestris var. mongolica, P. taeda, P. taiwanensis and P. thunbergii, but full development on these hosts is uncertain. The pest has three to five generations per year; winter is spent as larvae on branch tips, on tree trunks and in the soil. The females lay egg clusters on pine needles. Pupation occurs in cocoons attached to branches or needles. D. punctatus could enter the EU either as eggs, larvae or pupae in the foliage of plants for planting or cut branches, as larvae on wood with bark or as overwintering larvae in branches, crevices in the bark or in the litter of potted plants. However, Annex VI of 2019/2072 prohibits the introduction of D. punctatus hosts (Pinus spp.) from countries and areas where the pest occurs. There are climate zones where the pest occurs in Asia that also occur in the EU, though they are limited, which constitutes an uncertainty regarding establishment. The pest's main hosts are not grown in the EU. However, the fact that it attacks the North American Pinus echinata, P. elliottii and P. taeda in its Asian native area suggests a potential capacity to shift to pine species occurring in the EU territory. D. punctatus satisfies all the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest. Whether the Pinus commonly found in Europe could act as hosts is unknown but is fundamental, affecting the criteria of establishment and magnitude of impact.