Isolation of Phosphate-Solubilizing Fungi from Phosphate Mines and Their Effect on Wheat Seedling Growth

Abstract

Three phosphate-solubilizing fungi, identified as Penicillium expansum, Mucor ramosissimus, and Candida krissii, were isolated from phosphate mines (Hubei, People's Republic of China) and characterized. All the isolates demonstrated diverse levels of phosphate-solubilizing capability in National Botanical Research Institute's phosphate growth medium containing rock phosphate as sole phosphate source. Acidification of culture medium seemed to be the main mechanism for rock phosphate solubilization. Indeed, citric acid, oxalic acid, and gluconic acid were shown to be present in the culture medium inoculated with these isolates. Moreover, the isolates produced acid and alkaline phosphatases in culture medium, which may also be helpful for RP solubilization. A strong negative correlation between content of soluble phosphorus and pH (r = - 0.89; p < 0.01) in culture medium was observed in this study. All the isolates promoted growth, soil available phosphorus, phosphorus, and nitrogen uptake of wheat seedling in field soil containing rock phosphate under pot culture conditions, thus demonstrating the capability of these isolates to convert insoluble form of phosphorus into plant available form from rock phosphate, and therefore hold great potential for development as biofertilizers to enhance soil fertility and promote plant growth.

Effects of Phosphate Solubilizing Fungi on Growth and Yield of Haricot Bean (Phaseolus vulgaris L.) Plants

“…This may be due to better utilization of soluble phosphorus from the pool of available phosphorus in the soil due to solubilization of native and added phosphorus by the actions of the PSF isolates. This result is in agreement with previous reports of Xiao et al (2009) Increased nitrogen content in the leaves of haricot bean plants was recorded by the inoculation of PSF isolates compared to the control. The increase in nitrogen content of haricot bean might be due to increased nodulation as well as the positive interaction between P-solubilizing fungal isolates and root nodulating bacteria.…”

“…The increase in plant shoot height due to PSF inoculation along with RP application could be the result of increased transformation of P into available forms as indicated by the increased P in plants by the PSF isolates PSFAand PSFP. Similar results of increase in shoot height due to PSF inoculation has been reported on groundnut plant (Malviya et al, 2011), wheat (Xiao et al, 2009), chickpea (Yadav et al, 2011) and soy bean (Iman, 2008).…”

“…Several authors reported enhanced growth and yield on wheat (Xiao et al, 2009), soybean (Iman, 2008, maize (Richa et al, 2007;Bojinova et al, 2008) and pea (Kevin & Krista, 2001) through inoculation of P-solubilizing fungi (PSF) in rock phosphate (RP) amended soils. Emphasis is therefore, being placed on the possibility of utilization of rock phosphate, which may be made available to plants by microbiologically mediated processes in order to provide efficient and environmentally desirable approach compared to current technology for industrial P fertilizer production (Bojinova et al, 2008).…”

Evaluation of Phosphate Solubilizing Potential of Three Burkholderia Species Isolated from Green House Soils

“…However subsequently a significant drop in soluble phosphorus level was observed on later days when incubation period progressed. This may be due to the availability of soluble phosphorus in the culture medium, which has an inhibitory effect on further phosphate solubilization (Xiao et al, 2009). Some researchers suggested that it is due to the depletion of nutrients in the culture medium especially carbon source for the production of organic acids and microbial activity (Kang et al, 2002;Kim et al, 2005;Chaiharn and Lumyong, 2009).…”

Cloning and Expression of Cellulosome-Integrating Protein from Aspergillus niger H1 Improves Phosphate Solubilization

“…Most P are immobile and the available content of P is below the limit of plant growth in soils. Microorganisms play an important role in rendering insoluble P into soluble forms that are utilized by plants and prompt plant growth (Mehta et al, 2013;Xiao et al, 2009). Many studies have proven that acidification is the most process of P solubilization (Xiao et al, 2015;Sindhu et al, 2014;Rodríguez et al, 2006).…”