Interaction with Soil Bacteria Affects the Growth and Amino Acid Content of Piriformospora indica

Abstract

Exploration of the effect of soil bacteria on growth and metabolism of beneficial root endophytic fungi is relevant to promote favorable associations between microorganisms of the plant rhizosphere. Hence, the interaction between the plant-growth-promoting fungus Piriformospora indica and different soil bacteria was investigated. The parameters studied were fungal growth and its amino acid composition during the interaction. Fungus and bacteria were confronted in dual cultures in Petri dishes, either through agar or separated by a Perspex wall that only allowed the bacterial volatiles to be effective. Fungal growth was stimulated by Azotobacter chroococcum, whereas Streptomyces anulatus AcH 1003 inhibited it and Streptomyces sp. Nov AcH 505 had no effect. To analyze amino acid concentration data, targeted metabolomics was implemented under supervised analysis according to fungal-bacteria interaction and time. Orthogonal partial least squares-discriminant analysis (OPLS-DA) model clearly discriminated P. indica–A. chroococcum and P. indica–S. anulatus interactions, according to the respective score plot in comparison to the control. The most observable responses were in the glutamine and alanine size groups: While Streptomyces AcH 1003 increased the amount of glutamine, A. chroococcum decreased it. The fungal growth and the increase of alanine content might be associated with the assimilation of nitrogen in the presence of glucose as a carbon source. The N-fixing bacterium A. chroococcum should stimulate fungal amino acid metabolism via glutamine synthetase-glutamate synthase (GS-GOGAT). The data pointed to a stimulated glycolytic activity in the fungus observed by the accumulation of alanine, possibly via alanine aminotransferase. The responses toward the growth-inhibiting Streptomyces AcH 1003 suggest an (oxidative) stress response of the fungus.

Isolation and identification of mycorrhizal helper bacteria of Vaccinium uliginosum and their interaction with mycorrhizal fungi

“…Some MHB strains can synergize with a wide range of mycorrhizal fungi of different species; for example, Pseudomonad monteilii HR13 can bind to several fungal isolates, and all of them can promote the colonization of ectomycorrhizal and tussock mycorrhizae of Acacia ( Duponnois and Plenchette, 2003 ). In contrast, some MHB are extremely selective and can only interact with a particular fungus ( Leyva-Rojas et al, 2020 ). Since MHB and mycorrhizal fungi have specificity for mutual selection during co-evolution, it is necessary to screen MHB for different mycorrhizal types.…”

Responses of Bacterial Community Structure, Diversity, and Chemical Properties in the Rhizosphere Soil on Fruiting-Body Formation of Suillus luteus

“…Mycorrhization helper bacteria (MHB) are widespread around the roots of different plant–fungal mycorrhizae. Past literature has suggested that Agrobacterium [ 28 ], Burkholderia [ 29 ], Pseudomonas [ 30 ], Bacillus [ 31 ], Paenibacillus [ 32 ], and the actinomycete Streptomyces [ 33 ] are mycorrhization helper bacteria. In our findings, the mycorrhizal rhizosphere exhibited a lower Simpson index and higher Shannon and ACE indices ( Table 1 ), which indicated that this area possessed higher soil bacterial diversity and evenness.…”

The Free-Living Stage Growth Conditions of the Endophytic Fungus Serendipita indica May Regulate Its Potential as Plant Growth Promoting Microbe

“…The lack of these studies, especially the lack of field trials, limits our study’s contribution to the development of efficient S. indica -based PGPM, either S. indica alone or in consortium with bacteria. Indeed, studies demonstrating interactions between S. indica and soil bacteria are accumulating in recent years: (i) S. indica -bacteria interactions can benefit ( Jiang et al, 2018 ; Alabid et al, 2019 ) or affect ( Leyva-Rojas et al, 2020 ) S. indica ’s growth during the free-living stage; and (ii) S. indica -bacteria interactions have been shown to enhance crop production ( Guo et al, 2017 ; del Barrio-Duque et al, 2019 ; Dabral et al, 2020 ) and resistance to phytopathogens ( del Barrio-Duque et al, 2019 , 2020 ) and salt stress ( Heidarianpour et al, 2020 ). This recent trend further reinforces the need for synergy between fungal and bacterial endophyte research efforts ( Le Cocq et al, 2017 ), especially taking into consideration the bacteria intimately associated with S. indica ( Sharma et al, 2008 ; Guo et al, 2017 ; del Barrio-Duque et al, 2020 ).…”

“…The endophytic fungus Serendipita indica (former Piriformospora indica) fulfils the abovementioned advantages over AMF, and displays a high versatility of association with plants (Varma et al, 1999;Bertolazi et al, 2019;Heidarianpour et al, 2020;Leyva-Rojas et al, 2020). Further, S. indica grows inter-and intracellularly and forms a spiral structure similar to AMF's arbuscules, creating a symbiotic interface in the space between fungal hyphae and the cell wall (Schäfer and Kogel, 2009).…”