Antagonistic potential of some phosphate solubilizing fungi against some phyto-pathogenic fungi

Siada H Nasr,M A Marzouk,A S M Mousa,M M Yasser

doi:10.1186/s43088-021-00159-y

Abstract

BackgroundLittle phosphorus availability in soil is one of the major forces for crop production. Phosphate solubilizing fungi enhance available phosphorus from soils and contribute to achieve the plants phosphorus requirement. Phosphate solubilizing fungi are important component of soil microbiota and play an essential role in the biogeochemical cycling of phosphorus in natural ecosystems.ResultsThe study tested the potential of the isolated phosphate solubilizing fungi to inhibit the growth of Alternaria alternata, Fusarium solani, Geotrichum candidum, Rhizoctonia solani and Sclerotium rolfsii. A total of 137 fungal isolates were isolated and identified from 30 soil samples. Nine isolates solubilized inorganic phosphate (tricalcium phosphate). Eight of these isolates were isolated from the rhizosphere of Alhagi graecorum Boiss., Allium cepa L., Ehrharta calycina Sm., Ludwigia stolonifera (Guill. & Perr.) Raven, Mentha longifolia L., Phragmites communis Trin.,Triticum aestivum L. and Zea mays L., respectively and one isolate was isolated from island's free soil. Purified single spore cultures of these nine isolates were identified to species level by multi loci DNA barcoding using internal transcribed spacer1and 2 (ITS1 and ITS 2) of the rRNA gene cluster, Calmodulin (CaM) and β-tubulin)BenA) gene markers.ConclusionsThe isolated phosphate solubilizing fungi belonged to two genera, Aspergillus and Penicillium. The phosphate solubilization index ranged from 1 to 1.5. Aspergillius japonicus 2 had the highest solubilization index (1.5) and also had the highest inhibition percentage (70%) against Alternaria alternata. This isolate is promising for development of biocontrol agent of Fusarium solani, Geotricum candidium and Alternaria alternata. The highest phosphate solubilization by Aspergillius japonicus 2 was obtained by using sucrose as carbon source and also ammonium chloride and tryptophan as nitrogen source. The highest solubilization percentage was 78.2% at optimum glucose concentration (5%) while the pH value that gave the highest solubilization percentage (90%) was 3. After eight days of incubation of Aspergillius japonicus 2, the solubilization percentage reached its maximum value (80.2%).

Highlights

Little phosphorus availability in soil is one of the major forces for crop production
Phosphate solubilizing fungi (PSF) were isolated by the dilution plate method, this method was modified by Johnson et al [17]. 10 g of rhizosphere soil samples were taken at profile (0–10 cm) by using sterile auger and air dried for 24 h passed through a 0.5 mm soil sieve to remove large particles
All the isolated phosphate solubilizing fungi (PSF) belonged to Aspergillus and Penicillium genera

Summary

Introduction

Little phosphorus availability in soil is one of the major forces for crop production. Phosphate solubilizing fungi enhance available phosphorus from soils and contribute to achieve the plants phosphorus requirement. The continuous application of phosphate fertilizer and soil erosions are the common problems that reduce the crop productivity. Phosphate solubilizing fungi are considered as renewable and potential suppliers of soluble phosphorus. They have a great advantage for plants through solubilization and mineralization [5]. Aspergillus niger and Penicillium funiculosum are the most dominant soil fungi capable of phosphate solubilization [8]. The phosphate solubilizing fungi were Aspergillus (53.69%), Penicillium spp. Morales et al [10] isolated phosphate solubilizing fungi from different habitats such as agricultural land, arctic region, forest and mangrove

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