title: Transformation of inorganic P fractions of soil and plant growth promotion by phosphate-solubilizing ability of Penicillium oxalicum I1.
abstract: The solubilization of tricalcium phosphate is often considered as the standard for screening of most phosphate-solubilizing microorganisms (PSMs). However, usually the effect of large-scale application of PSM on the promotion of crop growth varies. This study presents an efficient method for screening and testing phosphate-solubilizing fungus that enhance plant growth. A fungus Penicillium oxalicum I1 (P-I1) was isolated and identified that had high ability of phosphate-solubilization and could utilize maize root exudates as sources, and propagate well in vitro and in soil. P-I1 excreted oxalic acid and reached 593.9 μg/ml, and the pH value was decreased from 6.90 to 1.65 in 26 h. The amount of P-I1 increased by 48-fold in 28 d and was maintained for 49 d in soil. PSM showed selectivity on the transformation of the different forms of phosphorus, a wide range of insoluble phosphates, such as Ca₈H₂(PO₄)₆·5H₂O, AlPO₄, FePO₄, and Ca10(PO₄)₆(OH)₂, were converted to soluble CaHPO₄in soil, and CaHPO₄was also inhibited from being converted into insoluble phosphate by P-I1. The Ca₂-P content reached 27.11 μg/g soil on day 28 at 20°C, which increased by 110.32%, and plant growth promotion was tested and verified, the results showed that maize yield increased remarkably than control after inoculated P-I1, maize yield increased maximum by 14.47%. The data presented that P-I1 appear attractive for exploring their plant growth-promoting activity and potential field application.
authors.affiliation: The Key Laboratory of Microbial Resources, Ministry of Agriculture / Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 10081, P. R. China.
authors.forename: Mingbo
authors.initials: M
authors.lastname: Gong
authors.forename: Peng
authors.initials: P
authors.lastname: Du
authors.forename: Xue
authors.initials: X
authors.lastname: Liu
authors.forename: Changxiong
authors.initials: C
authors.lastname: Zhu
mesh_terms: D002130:Calcium Phosphates / Q000378:metabolism; D002681:China; D010070:Oxalates / Q000378:metabolism*; D010407:Penicillium / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D010758:Phosphorus / Q000378:metabolism; D010802:Phylogeny; D063245:Plant Development / Q000502:physiology*; D018517:Plant Roots / Q000378:metabolism; D012987:Soil / Q000737:chemistry; D012988:Soil Microbiology; D012995:Solubility; D003313:Zea mays / Q000254:growth & development*
chemical_list: D002130:Calcium Phosphates; D010070:Oxalates; D010710:Phosphates; D012987:Soil; D010758:Phosphorus; C018392:tricalcium phosphate