Native Rhizospheric and Endophytic Fungi as Sustainable Sources of Plant Growth Promoting Traits to Improve Wheat Growth under Low Nitrogen Input

Abstract

Wheat crops require effective nitrogen fertilization to produce high yields. Only half of chemical N2 fertilizers are absorbed into plants while the rest remains in the soil, causing environmental problems. Fungi could maximize nitrogen absorption, and from an environmental and biodiversity point of view, there is an urgent necessity for bioprospecting native fungi associated with wild plants growing in harsh environments, e.g., St. Katherine Protectorate (SKP) in the arid Sinai. Recovered taxa, either endophytic and/or rhizospheric, were screened for their plant growth-promoting (PGP) traits. Eighteen fungal isolates (15 rhizospheric and 3 endophytic) belonging to anamorphic ascomycetes were recovered from 9 different wild plants, and their PGP traits (indole-3-acetic acid [IAA] production, phosphate solubilization, siderophore production, and hydrolytic enzyme production) were measured. Rhizospheric isolate NGB-WS14 (Chaetosphaeronema achilleae) produced high levels of IAA (119.1 μg mL−1) in the presence of tryptophan, while NGB-WS 8 (Acrophialophora levis) produced high IAA levels (42.4 μg mL−1) in the absence of tryptophan. The highest phosphate-solubilizing activity (181.9 μg mL−1) was recorded by NGB-WFS2 (Penicillium chrysogenum). Endophytic isolate NGB-WFE16 (Fusarium petersiae) exhibited a high percentage level of Siderophore Unit (96.5% SU). All isolates showed variability in the secretion of extracellular hydrolytic enzymes. Remarkably, all isolates had antagonistic activity (55.6% to 87.3% suppression of pathogen growth) against the pathogenic taxon Alternaria alternata (SCUF00001378) in the dual-assay results. Out of the 18 isolates, 4 rhizospheric and 1 endophytic isolate showed significant increases in shoot dry weight and shoot nitrogen and chlorophyll content of wheat plants subjected to low inputs of chemical nitrogen (N) fertilizers (50% reduction) compared with the non-inoculated control in a pot experiment. Potent taxa were subjected to sequencing for molecular confirmation of phenotypic identification. The retrieved ITS sequences in this study have been deposited in GenBank under accession numbers from LC642736 to LC642740. This study considered the first report of endophytic fungi of Cheilanthes vellea, a wild plant with PGPF which improves wheat growth. These results recommend using PGPF as inoculants to alleviate low nitrogen fertilization.

The Potential of Endophytic Fungi for Enhancing the Growth and Accumulation of Phenolic Compounds and Anthocyanin in Maled Phai Rice (Oryza sativa L.)

“…Therefore, PGP substance properties are more important than the efficient production of siderophores. These results are consistent with Mohamed et al [ 58 ], who showed that P. chrysogenum NGB-WFS2, which could highly solubilize phosphorus and IAA production, while having a low percentage of siderophore production, could promote plant growth better than A. versicolor NGB-WFS9, which could produce a high amount of siderophores. However, it was found that chemical fertilizers were more effective in promoting some characteristics of Maled Phai rice than endophytes.…”

Importance of Dark Septate Endophytes in Agriculture in the Face of Climate Change

“…Most of the phosphorus present in the soil can be found in the form of phosphates, which form compounds together with metals, minerals (inorganic substances), and organic materials (organic substances) [91]. Although P is abundantly found in agricultural soils, most of it is present in its insoluble form; thus, it cannot be directly used by plants [92]. Consequently, to achieve an optimal crop yield, synthetic fertilisers with P are used; however, only approximately 30% of the added P can be used by crops as a large portion of the P remains immobilised in the form of insoluble phosphate or migrates in the soil [93].…”

“…This increased Fe intake may be related to the ability of endophytic microorganisms to produce siderophores under limiting iron stress conditions [125][126][127]. Moreover, these siderophores produced by endophytes tend to have more affinity for Fe 3+ ions than the phytosiderophores produced by plants [92]. P. fortinii is capable of synthetising hydroxamate siderophore, and such synthesis has been linked to the increased incorporation of Fe 3+ by the host plant [124].…”

Preliminary screening of endophytic fungi hosted some wild plants in North Sinai for biogenic production of silver nanoparticles

“…These fungi synthesize a wealth of functional metabolites like alkaloids, terpenoids, amines, flavonoids, steroids, and phenolic compounds (Ding et al 2008). Notably, they are recognized for their production of novel antimicrobial agents, anticancer compounds such as Taxol, and industrially valuable enzymes (Salem & Abdel-Azeem 2014;Netala et al, 2016;Mohamed et al 2022;Moubasher et al 2022).…”