Maize rhizosphere in Sichuan, China, hosts plant growth promoting Burkholderia cepacia with phosphate solubilizing and antifungal abilities.
Plant growth-promoting rhizobacteria promote plant growth by direct and indirect mechanisms. We isolated twelve bacterial strains showing different degrees of phosphate solubilizing activity from maize rhizosphere. Four isolates solubilized over 300 μg mL⁻¹ phosphate from insoluble Ca₃(PO₄)₂, with isolate SCAUK0330 solubilizing over 450 μg mL⁻¹. Based on the 16S rRNA gene sequence analysis SCAUK0330 was identified as Burkholderia cepacia. SCAUK0330 grew at 10-40 °C and pH 4.0-10.0, tolerated up to 5% NaCl, and showed antagonism against nine pathogenic fungi. SCAUK0330 promoted the growth of both healthy and Helminthosporium maydis infected maize plants, indicating that the isolate was a good candidate to be applied as a biofertilizer and a biocontrol agent under a wide range of environmental conditions.The expression of a single SCAUK0330 gene gave E. coli a pH decrease linked ability to solubilize phosphate. The nucleotide and the deduced amino acid sequences of this phosphate solubilization linked gene showed high degree of sequence identity with B. cepacia E37gabY. The production of gluconic acid is considered as the principle mechanism for phosphate solubilization. In agreement with the proposed periplasmic location of the gluconic acid production, the predicted signal peptide and transmembrane regions implied that GabY is membrane bound.
Department of Microbiology, College of Resource and Environmental Sciences, Sichuan Agricultural University, Yaan 625000, PR China.
Ke
K
Zhao
Petri
P
Penttinen
Xiaoping
X
Zhang
Xiaoling
X
Ao
Maoke
M
Liu
Xiumei
X
Yu
Qiang
Q
Chen
D000935:Antifungal Agents / Q000378:metabolism*; D016956:Burkholderia cepacia / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002681:China; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005658:Fungi / Q000187:drug effects / Q000254:growth & development; D008969:Molecular Sequence Data; D010710:Phosphates / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D058441:Rhizosphere; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D003313:Zea mays / Q000254:growth & development* / Q000382:microbiology*
D000935:Antifungal Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D010710:Phosphates; D012336:RNA, Ribosomal, 16S
Antifungal abilities; Mineral phosphate solubilizing gene; Phosphate solubilizing bacterial; Plant growth-promoting rhizobacteria