植物抗镉内生细菌筛选及其对小麦幼苗耐镉能力的影响
文章编号：2095-1191（2018）12-2379-08
Screening of cadmium-resistant endophytic bacteria and its effect on enhancing cadmium tolerance of wheat seeding
LIU Jun-sheng1，2， XIE Xiu-chao1，2*， LUO Yang-lan1，2， DENG Bai-wan1，2，
CAO Nai-xin1，2， JIA Jiao1，2
（1Shaanxi Provincial Engineering Research Center of Edible & Medicinal Fungi， Shaanxi University of Technology，Hanzhong， Shaanxi 723001， China; 2School of Biological Science & Engineering， Shaanxi University of Technology，
Hanzhong， Shaanxi 723001， China）
Abstract：【Objective】In order to provide the dominant strains for the remediation of soil polluted by cadmium via plant-microbe combined remediation system，the cadmium-resistant endophytic bacteria were screened. 【Method】Endophytic bacteria were isolated from Periploca sepium Bunge and Melilotus suaveolens Ledeb in Qinling Mountains lead-zinc tai-ling area，and those with high cadmium-resistant level were screened and identified by analysis of 16S rDNA sequence. The biological characteristics including its removal rate of Cd2+， the activity of indole acetic acid （IAA），siderophore and 1-aminocyclopropane-1-carboxylic acid （ACC） deaminase were measured. Potted plant experiment was used to test whe-ther the strains improved the tolerance of wheat seeding to cadmium. 【Result】The results showed that 11 cadmium-resistant endophytic bacteria（GS3，CR4，CG7，GR31，GR38，GR42，GR43，GR44，GR45，GR49 and GR54） were isolated and screened with the condition of 800 mg/L Cd2+ concentration. All the strains were identified as Bacillus sp. Biological chara-cteristics showed that the removal rate of Cd2+ for all 11 endophytic bacteria were in the range of 14.56%-79.45% at 800 mg/L Cd2+ concentration level， and removal rate of Cd2+ for the strain GR44 was the highest. There were 7 strains which had activity of IAA and strain GR44，GR49，CG7 were higher. All the 11 strains contained siderophore activity and ACC deaminase activity. Siderophore activity of GR44 was the highest， and ACC deaminase activity of GR54 was the highest. Wheat potted experiment showed that endophytic bacteria GR44 could significantly improve the tolerance of wheat seedling to cadmium（P<0.05）. 【Conclusion】As the selected cadmium-resistant endophytic bacteria， GR44 can be used as dominant strains for constructing the plant-microbe combined remediation system for soil polluted by cadmium，and has positive significance for reclamation of mining area.