Leguminosae native nodulating bacteria from a gold mine As-contaminated soil: Multi-resistance to trace elements, and possible role in plant growth and mineral nutrition.
Efficient N2-fixing Leguminosae nodulating bacteria resistant to As may facilitate plant growth on As-contaminated sites. In order to identify bacteria holding these features, 24 strains were isolated from nodules of the trap species Crotalaria spectabilis (12) and Stizolobium aterrimum (12) growing on an As-contaminated gold mine site. 16S rRNA gene sequencing revealed that most of the strains belonged to the group of α-Proteobacteria, being representatives of the genera Bradyrhizobium, Rhizobium, Inquilinus, Labrys, Bosea, Starkeya, and Methylobacterium. Strains of the first four genera showed symbiotic efficiency with their original host, and demonstrated in vitro specific plant-growth-promoting (PGP) traits (production of organic acids, indole-3-acetic-acid and siderophores, 1-aminocyclopropane-1-carboxylate deaminase activity, and Ca3(PO4)2solubilization), and increased resistance to As, Zn, and Cd. In addition, these strains and some type and reference rhizobia strains exhibited a wide resistance spectrum to β-lactam antibiotics. Both intrinsic PGP abilities and multi-element resistance of rhizobia are promising for exploiting the symbiosis with different legume plants on trace-element-contaminated soils.
a Biology Department , Federal University of Lavras (UFLA) , Lavras , Minas Gerais , Brazil.|b Soil Science Department , UFLA , Lavras , Minas Gerais , Brazil.|c Soil Department , Federal University of Santa Maria (UFSM) , Santa Maria , Rio Grande do Sul , Brazil.
Wesley de M
WM
Rangel
b Soil Science Department , UFLA , Lavras , Minas Gerais , Brazil.
Silvia M
SM
de Oliveira Longatti
b Soil Science Department , UFLA , Lavras , Minas Gerais , Brazil.|c Soil Department , Federal University of Santa Maria (UFSM) , Santa Maria , Rio Grande do Sul , Brazil.
Paulo A A
PAA
Ferreira
b Soil Science Department , UFLA , Lavras , Minas Gerais , Brazil.
Daiane S
DS
Bonaldi
b Soil Science Department , UFLA , Lavras , Minas Gerais , Brazil.
Amanda A
AA
Guimarães
d Centre for Environmental Sciences, Hasselt University , Diepenbeek , Belgium.
Sofie
S
Thijs
d Centre for Environmental Sciences, Hasselt University , Diepenbeek , Belgium.
Nele
N
Weyens
d Centre for Environmental Sciences, Hasselt University , Diepenbeek , Belgium.
Jaco
J
Vangronsveld
b Soil Science Department , UFLA , Lavras , Minas Gerais , Brazil.
Fatima M S
FMS
Moreira
D001151:Arsenic / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D007887:Fabaceae / Q000382:microbiology*; D006046:Gold; D008903:Minerals; D008906:Mining; D063245:Plant Development; D010944:Plants; D012336:RNA, Ribosomal, 16S; D012987:Soil; D012989:Soil Pollutants / Q000378:metabolism*; D014131:Trace Elements
D008903:Minerals; D012336:RNA, Ribosomal, 16S; D012987:Soil; D012989:Soil Pollutants; D014131:Trace Elements; D006046:Gold; D001151:Arsenic
biological N2 fixation; plant growth-promoting; trace elements multi-resistance; β-lactam antibiotics resistance