The Plant-Growth-Promoting Fungus, Mortierella elongata: Its Biology, Ecological Distribution, and Growth-Promoting Activities

Recent studies show that Mortierella elongata can perform plant-growth promotion across different types of crops, including bahiagrass, corn, tomato, squash, and watermelon. Compared to the well-known species that have plant-growth-promotion abilities (e.g., mycorrhizal fungi, Trichoderma), growers, agents, and stakeholders are not familiar with "Mortierella" despite the important role these fungal taxa play in promoting the growth of their crops. This new 5-page publication of the UF/IFAS Department of Soil and Water Sciences provides a brief overview of Mortierella from biological, taxonomical, ecological, and functional perspectives to help readers learn the biology and potential modes of action of this fungus. Written by Hui-Ling Liao.https://edis.ifas.ufl.edu/ss679

Increased Flower Production of Calibrachoa x hybrida by the Soil Fungus Mortierella elongata1

Calibrachoa (Calibrachoa x hybrida) is a highly valued solanaceous flowering ornamental plant, characterized by its drought-hardiness, abundant flowering, and diverse flower colors. Recently, the saprobic soil fungus Mortierella elongata was isolated as a root endophyte from eastern cottonwood (Populus deltoides) and identified as a potential biological amendment for bioenergy and food crops. Two greenhouse experiments were conducted by transplanting rooted cuttings of Calibrachoa cv. ‘Kabloom Deep Blue' into a potting media mixture amended with 1 or 2% volume mix ratio of millet seed colonized with one of four isolates of M. elongata. Plants were assessed weekly for flower production and 86 days post inoculation for leaf/stem, root, and total dry weight. M. elongata strain 624- significantly increased flower production compared to the non-inoculated millet seed controls at 6 and 7 wk post amendment in both experiments. Above and below ground vegetative dry weight for plants grown in potting media mixture amended with M. elongata isolates varied across isolates, fungal amendment concentrations, and experiments. Our results suggest that potting media mixture amended with M. elongata strain 624- can increase flower production of Calibrachoa during peak marketable periods. Index words: Calibrachoa, plant growth promotion, plant reproduction, biological amendment. Species used in this study: Calibrachoa (Calibrachoa x hybrida); Mortierella elongata Linnem.

Functional convergence in the decomposition of fungal necromass in soil and wood

ABSTRACT Understanding the post-senescent fate of fungal mycelium is critical to accurately quantifying forest carbon and nutrient cycling, but how this organic matter source decomposes in wood remains poorly studied. In this study, we compared the decomposition of dead fungal biomass (a.k.a. necromass) of two species, Mortierella elongata and Meliniomyces bicolor, in paired wood and soil plots in a boreal forest in northern Minnesota, USA. Mass loss was quantified at four time points over an 8-week incubation and the richness and composition of the fungal communities colonizing fungal necromass were characterized using high-throughput sequencing. We found that the structure of fungal decomposer communities in wood and soil differed, but, in both habitats, there was relatively rapid decay (∼30% remaining after 56 days). Mass loss was significantly faster in soil and for high-quality (i.e. high nitrogen and low melanin) fungal necromass. In both habitats, there was a clear trajectory of early colonization by opportunistic fungal taxa followed by colonization of fungi with greater enzymatic capacities to degrade more recalcitrant compounds, including white-rot and ectomycorrhizal fungi. Collectively, our results indicate that patterns emerging regarding substrate quality effects on fungal necromass decomposition in soil and leaf litter can be largely extended to fungal necromass decomposition in wood.

Algal-fungal symbiosis leads to photosynthetic mycelium

Mutualistic interactions between free-living algae and fungi are widespread in nature and are hypothesized to have facilitated the evolution of land plants and lichens. In all known algal-fungal mutualisms, including lichens, algal cells remain external to fungal cells. Here, we report on an algal–fungal interaction in which Nannochloropsis oceanica algal cells become internalized within the hyphae of the fungus Mortierella elongata. This apparent symbiosis begins with close physical contact and nutrient exchange, including carbon and nitrogen transfer between fungal and algal cells as demonstrated by isotope tracer experiments. This mutualism appears to be stable, as both partners remain physiologically active over months of co-cultivation, leading to the eventual internalization of photosynthetic algal cells, which persist to function, grow and divide within fungal hyphae. Nannochloropsis and Mortierella are biotechnologically important species for lipids and biofuel production, with available genomes and molecular tool kits. Based on the current observations, they provide unique opportunities for studying fungal-algal mutualisms including mechanisms leading to endosymbiosis.

Primer reporte de Mortierella elongata como patógeno del cultivo del aguacate en Michoacán, México

Antecedentes: Las especies del género Mortierella prosperan usualmente como saprófitas en el suelo y materia orgánica de diversos ecosistemas forestales. Tradicionalmente, se han aislado de los sistemas radicales de diversas especies vegetales. Adicionalmente, investigaciones realizadas en suelo de cultivo de aguacate para lograr la purificación de Pythophthora. cinnamomi indican que Mortierella spp. son hongos contaminantes, sin mencionar su patogenicidad.Objetivo: Esta investigación tuvo como objetivo identificar la presencia de Mortierella sp. y evaluar su posible patogenicidad en el cultivo del aguacate.Métodos: Las cepas se aislaron de suelo de huertas ubicadas en los principales municipios productores de aguacate en el estado de Michoacán. Las cepas fueron identificadas y se sometieron a pruebas de patogenicidad con plantas de aguacate de tres meses de edad y con plántulas con seis hojas verdaderas.Resultados y conclusión:

Amauroascus kuehnii and other fungi isolated from a deer horn in Poland

Four keratinophilic fungi isolated from deer horn collected in Gorce National Park (Poland) are reported: Amauroascus kuehnii Arx with its malbranchea-like anamorph, Isaria fumosorosea Wize, Mortierella elongata Linnem., and Penicillium spinulosum Thom s.l. The record of Amauroascus kuehnii is its second locality in Europe, and keratin deer horn is a new substrate for this fungus.