Phosphate solubilization and indole-3-acetic acid (IAA) produced by Colletotrichum gloeosporioides and Aspergillus fumigatus strains isolated from the rhizosphere of Dillenia indica L

Plants form associations with different microbes; some promote their growth and protect from biotic and abiotic stresses in different ways. However, the biological role of fungi associated with the rhizosphere of medicinal plants is not well explored. In the present study, Colletotrichum gloeosporioides, and Aspergillus fumigatus isolated from the rhizosphere of Dillenia indica were screened for their phosphate solubilization and indole-3-acetic acid (IAA) production potential. The selected fungal strains were identified by macroscopic, microscopic, and molecular characteristics. Phosphate solubilization was qualitatively and quantitatively evaluated using Pikovskaya's (PVK) agar and PVK broth medium using different substrates such as AlPO4, Ca-3(PO4)(2), and FePO4. Colletotrichum gloeosporioides and Aspergillus fumigatus with respect to the phosphate source showed solubilization index (SI) of 1.7 +/- 0.03 and 2.1 +/- 0.04, and solubilized phosphate up to 138.8 +/- 0.058 mu g/mL and 121.6 +/- 0.062 mu g/mL. These fungal strains are also good producers of IAA and significantly enhance the growth of Vigna radiata and Cicer arietinum seedlings. This is the first report on A. fumigatus and C. gloeosporioides from the rhizosphere of Dillenia indica and their phosphate solubilization and IAA production ability.

Automated summary

This study reports for the first time the phosphate solubilization and IAA production abilities of Aspergillus fumigatus and Colletotrichum gloeosporioides isolated from the rhizosphere of Dillenia indica. These fungi not only solubilize phosphate, but also produce IAA, significantly enhancing the growth of Vigna radiata and Cicer arietinum seedlings.