Differentiation and response mechanisms of the endophytic flora of plants ecologically restored in the ilmenite area

Xin Yu ¹ Junqiang Xu ² Ziping Zou ¹ Yunfeng Zhang ¹ Peng Wu ² Qiang Li ^1*

• ¹ Chengdu University, Chengdu, China
• ² Yunnan Agricultural University, Kunming, Yunnan, China

Heavy metal contamination in soils poses a severe environmental challenge, with particular concern surrounding abandoned mining areas. To address ecological restoration in these regions, this study investigated the ecological restoration of abandoned ilmenite mines by seven common plants. The results revealed that the abandonment of ilmenite significantly increased the contents of total phosphorus, total potassium, available potassium, iron, and lead in the surrounding soils. It also affected the richness and diversity of endophytic bacterial communities. Pvi had the highest richness, while Tsi had the lowest richness (P < 0.05). A total of 28 phylums, 69 classs, 171 orders, and 521 genus were identified; the nine core OTUs shared.Beta diversity analysis revealed that the community structure of the endophytic bacteria differed during the remediation process at the ilmenite site. Functional prediction revealed upregulation of Dco transporter protein function, DNA-binding transcriptional regulators, glyoxalase or related metal-dependent hydrolases, acyl coenzyme A synthetases, ATPase components, amino acid synthesis, and cellular respiration-related functions. Pearson correlation analysis revealed that the SOC, TK, AN, AK, and Zn contents were significantly correlated with α diversity.Redundancy analysis (RDA) revealed that Actinobacteriota was significantly positively correlated with soil SOD, AN, TN, and TK contents. This study revealed the interactions among plants, endophytic bacteria and soil pollutants, laying a theoretical basis for screening specific plant endophytic bacteria for ecological restoration.