Physiological characterization of coprophilous fungal isolates that behave as plan

MIRANDA, VICTORIA; SCERVINIO J.M.; BARROS, JOHANA; RODRIGUEZ, M.A.; FRACCHIA, SEBASTIÁN

AUSTRALIAN JOURNAL OF SOIL RESEARCH

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2020

0004-9573

Different fungal isolates closely related to Zopfiella erostrata and Cercophora caudata have been found to colonize plant root tissues in an asymptomatic way in the Monte Desert biome of La Rioja province (Argentina). This interaction has been newly discovered, and the role of these fungi in their desert habitat has never been studied in detail. The objective of this study was to evaluate eight fungal isolates (closely related to Z. erostrata and C. caudata), by means of specific physiological traits that could have implications in their interaction with the host plant. The selected isolates, four endophytic and four rhizospheric ones, were characterized for their ability to produce indole acetic acid, solubilize and mineralize phosphorous, and utilize different nitrogen sources. In addition, we evaluated organic acid production and phosphatases activities as mechanisms of P recycling. These analyses revealed that most isolates produce indole, and that all isolates were able to solubilize and mineralize phosphorous, although in different degrees. Furthermore, the production of organic acids correlated with P solubilization levels, which may enhance P availability in soils. Nitrogen utilization was variable among the isolates, without specific patterns concerning the different sources and fungal isolates tested. Our results demonstrated that the fungal isolates have great variability, probably because they complete the teleomorphic phase in their habitats, generating viable meiotic spores, in addition to the active dispersion of these fungi by the underground rodent Ctenomys aff. knightii from which they were isolated. Although the isolates were variable, the endophytic ones exhibited improvement in all the phosphorous parameters measured. This can be explained by the ability of these isolates to intimately colonize root tissues, producing a stronger effect in the host plants, while the colonization by rhizospheric isolates is produced superficially in the rhizoplane. The high occurrence of this interaction, as well as the physiological traits detected, suggest that this kind of fungi could play an important ecological role in the Monte desert environment, benefitting the establishment and growth of new seedlings in areas occupied by the rodents