# Marine macroalgae-associated fungi from Yacila and Los Cangrejos beaches (Northern Peru) and previously selected marine bacteria evaluated as plant growth promoters in maize under saline stress

## TL;DR

This study explores marine fungi and bacteria from Peruvian beaches and their potential to help maize grow in salty soil.

## Contribution

The study identifies new marine fungi and bacteria with plant growth-promoting traits under saline stress.

## Key findings

- Twelve marine fungi and ten marine bacteria were isolated and evaluated for growth-promoting traits.
- Three fungal and two bacterial strains showed significant antimicrobial and growth-promoting properties.
- Aspergillus sydowii CCDF2 notably enhanced maize growth under saline stress.

## Abstract

The diversity of marine fungi associated with macroalgae in Peru remains largely unknown, and no studies have provided holistic data on their biodiversity or their role as plant growth promoters in maize under salinity stress conditions. Endophytic and epiphytic fungi were isolated from the macroalgae Caulerpa sp., Ulva sp., Ahnfeltiopsis sp., and Chondracanthus chamissoi, collected from Yacila and Cangrejos beaches (Piura, Peru), while marine bacteria were provided by the Microbial Biotechnology Research Laboratory of the National University of Frontera. The growth-promoting properties of these marine microorganisms were evaluated prior to their inoculation in maize. Fungal isolates were phylogenetically characterized by ITS sequencing as Penicillium sp. YAFL13, Penicillium sp. YUFE7, Talaromyces stollii YAFL19, T. stollii YAFL4, T. amestolkiae YCFR3, Aspergillus sydowii CCDF2, A. sydowii YFep2, and A. sydowii YFep3. In total, 12 marine fungi were isolated and used in the assays along with 10 marine bacteria. Based on antimicrobial activity, IAA synthesis, siderophore production, phosphate solubilization, and hydrolytic enzyme production, three fungal strains (Penicillium sp. YAFL13, A. sydowii CCDF2, and A. sydowii YFep2) and two bacterial strains (Bacillus sp. YCFR5 and Pantoea agglomerans YAFL6) were selected. Among them, A. sydowii CCDF2 significantly enhanced maize growth parameters, highlighting its promising potential as a plant inoculant. This study represents one of the few reports on marine microorganisms associated with marine macroalgae, revealing a valuable fungal diversity and its potential role in promoting maize growth under saline stress conditions.