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Characterization of cadmium‐resistant rhizobacteria and their promotion effects on Brassica napus growth and cadmium uptake
Author(s) -
Li Xingjie,
Yan Zhenning,
Gu Daguo,
Li Dongbo,
Tao Yu,
Zhang Daofeng,
Su Liantai,
Ao Yansong
Publication year - 2019
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.201800656
Subject(s) - rhizobacteria , siderophore , chryseobacterium , sphingomonas , cupriavidus necator , biology , brassica , phytoremediation , food science , horticulture , microbiology and biotechnology , botany , inoculation , bacteria , 16s ribosomal rna , rhizosphere , ecology , genetics , contamination , polyhydroxyalkanoates
Excessive cadmium (Cd) accumulation in soil can adversely affect plants, animals, microbes, and humans; therefore, novel and uncharacterized Cd‐resistant plant‐growth‐promoting rhizobacteria (PGPR) are required to address this issue. In the paper, 13 bacteria were screened, their partial 16S rRNA sequences determined, and the isolates, respectively, clustered into Curtobacterium (7), Chryseobacterium (4), Cupriavidus (1), and Sphingomonas (1). Evaluation of PGP traits, including indole‐3‐acetic acid (IAA) production, 1‐aminocyclopropane‐1‐carboxylate (ACC) deaminase activity, siderophore secretion, and cyanhydric acid production, identified Cupriavidus necator GX_5, Sphingomonas sp. GX_15, and Curtobacterium sp. GX_31 as promising candidates for PGPR based on high IAA or ACC deaminase production. Additionally, root‐elongation assays indicated that inoculating GX_5, _15, or _31 increased Brassica napus root length both in the presence and absence of Cd by 19.75–29.96% and 19.15–31.69%, respectively. Pot experiments indicated that inoculating B. napus with GX_5, _15, and _31 significantly increased the dry weight of above‐ground tissues and root biomass by 40.97–85.55% and 18.99–103.13%, respectively. Moreover, these isolates significantly increased Cd uptake in the aerial parts and root tissue of B. napus by 7.38–11.98% and 48.09–79.73%, respectively. These results identified GX_5, _15, or _31 as excellent promoters of metal remediation by using microorganism‐associated phytoremediation.