Nascimento Erica, Klepa Milena Serenato, Olchanheski Luiz Ricardo, de Alencar Almeida Mayara, Chicora Kauane, Prestes Leticia, Rodrigues Elisete Pains, Hungria Mariangela, da Silva Batista Jesiane Stefania
Departamento de Biologia Estrutural, Molecular E Genética, Universidade Estadual de Ponta Grossa, C.P. 6001, Ponta Grossa, PR, 84030-900, Brazil.
Embrapa Soja, C.P. 40061, Londrina, PR, 86805-981, Brazil.
Braz J Microbiol. 2024 Dec;55(4):3321-3334. doi: 10.1007/s42770-024-01472-1. Epub 2024 Aug 12.
The phosphate (P)-solubilizing potential of rhizobia isolated from active root nodules of Brazilian native Mimosa and Desmodium was assessed. Out of the 15 strains selected, five Paraburkholderia isolated from Mimosa spp. grown in rocky outcrops stood out. The Ca(PO)-solubilizing efficiency of these strains ranged from 110.67 to 356.3 mgL, with less expressive results for FePO and Al(HPO) that might be attributed to the low solubility of these two P compounds. Paraburkholderia strains CNPSo 3281 and CNPSo 3076 were the most efficient siderophore producers (44.17 and 41.87 µMol EDTA) and two of the top FePO solubilizers. Acidification of the culture media was observed for all the strains and P sources. Regarding Ca(PO) solubilization the main organic acids detected were glucuronic (an important component of rhizobia exopolysaccharides) and gluconic acids. Genomic analysis of P. nodosa CNPSo 3281 and CNPSo 3076 along with other phosphate-solubilizing Paraburkholderia species of the genus pointed out a conserved gene organization of phoUBR, pstSCAB, ppk and ppx. Greenhouse experiment revealed that P. nodosa CNPSo 3281 and CNPSo 3076 promoted maize growth under low P. Our results indicate the relevance of native rhizobia as multifunctional plant-associated bacteria and the rocky outcrops ecosystems as hotspots for bioprospection.
对从巴西本土含羞草和山蚂蝗的活性根瘤中分离出的根瘤菌的解磷潜力进行了评估。在所选的15个菌株中，从生长在岩石露头处的含羞草属植物中分离出的5株类伯克霍尔德氏菌表现突出。这些菌株对Ca₃(PO₄)₂的解磷效率在110.67至356.3 mg/L之间，对FePO₄和Al(HPO₄)₂的解磷效果较差，这可能归因于这两种磷化合物的低溶解度。类伯克霍尔德氏菌菌株CNPSo 3281和CNPSo 3076是最有效的铁载体产生菌（分别为44.17和41.87 µMol EDTA），也是FePO₄解磷能力最强的菌株中的两个。观察到所有菌株和磷源都会使培养基酸化。关于Ca₃(PO₄)₂的溶解，检测到的主要有机酸是葡萄糖醛酸（根瘤菌胞外多糖的重要成分）和葡萄糖酸。对类伯克霍尔德氏菌CNPSo 3281和CNPSo 3076以及该属其他解磷类伯克霍尔德氏菌进行的基因组分析指出，phoUBR、pstSCAB、ppk和ppx基因组织保守。温室实验表明，类伯克霍尔德氏菌CNPSo 3281和CNPSo 3076在低磷条件下促进了玉米生长。我们的结果表明，本土根瘤菌作为多功能植物相关细菌具有重要意义，而岩石露头生态系统是生物勘探的热点。
