ArticlePDF Available

The impact of host plant (Pinus thunbergii) on the mycelial features of the ectomycorrhizal fungus Rhizopogon roseolus

Taylor & Francis
Mycologia
Authors:
Ivan Permana Putra at Bogor Agricultural University
Ivan Permana Putra
Tadanori Aimi at Tottori University
Tadanori Aimi
Norihiro Shimomura at Tottori University
Norihiro Shimomura
Download full-text PDF
Read full-text
Download citation

Abstract

The impact of host plant on the mycelial features of mycorrhizal symbiont and its characteristics has been poorly investigated. This study aimed to compare and quantify (statistically tested) some of the mycelial features of an ectomycorrhiza (ECM)-forming fungus with and without the ECM host. The ECM-forming fungus, Rhizopogon roseolus, inoculated with or without Pinus thunbergii on both rich and poor nutrient media, was observed under laboratory conditions. On rich medium, fungi with the host had the highest colony diameter and consistently produced the highest hyphal length relative to fungi on other media. Thus, the host had a significant impact on the mycelium production of R. roseolus in both rich and poor media. Further, fungi without the host had a higher number of hyphal anastomoses per hyphal length on both poor and rich media than fungi with the host in the same medium. Anastomosis, which refers to the fusion of two parallel hyphae, was evident in all experiments. However, there was no significant impact of the host on the number of hyphal anastomoses. In addition, fungi without the host had more frequent hyphal branching on both rich and poor media than fungi with the host. The occurrence of a host only had a significant impact on the formation of the hyphal branch on poor medium. Further, a chlamydospore-like structure was identified, which had a higher diameter when formed with the host on both rich and poor media. The present data provide new insights into the host plant's impact on the mycelial features of ECM-forming fungi.
Content uploaded by Ivan Permana Putra
Author content
All content in this area was uploaded by Ivan Permana Putra on Aug 29, 2022
Content may be subject to copyright.
The impact of host plant (Pinus thunbergii) on the mycelial features of the
ectomycorrhizal fungus Rhizopogon roseolus
Ivan Permana Putra
a,b
, Tadanori Aimi
c
, and Norihiro Shimomura
c
a
The United Graduate School of Agricultural Sciences, Tottori University, 4-101 Koyama-cho Minami, Tottori 680-8553, Japan;
b
Department of
Biology, Faculty of Mathematics and Natural Sciences, IPB University, Bogor 16680, Indonesia;
c
Faculty of Agriculture, Tottori University, 4-101
Koyama-cho Minami, Tottori 680-8553, Japan
ABSTRACT
The impact of host plant on the mycelial features of mycorrhizal symbiont and its characteristics has
been poorly investigated. This study aimed to compare and quantify (statistically tested) some of
the mycelial features of an ectomycorrhiza (ECM)-forming fungus with and without the ECM host.
The ECM-forming fungus, Rhizopogon roseolus, inoculated with or without Pinus thunbergii on both
rich and poor nutrient media, was observed under laboratory conditions. On rich medium, fungi
with the host had the highest colony diameter and consistently produced the highest hyphal
length relative to fungi on other media. Thus, the host had a signicant impact on the mycelium
production of R. roseolus in both rich and poor media. Further, fungi without the host had a higher
number of hyphal anastomoses per hyphal length on both poor and rich media than fungi with the
host in the same medium. Anastomosis, which refers to the fusion of two parallel hyphae, was
evident in all experiments. However, there was no signicant impact of the host on the number of
hyphal anastomoses. In addition, fungi without the host had more frequent hyphal branching on
both rich and poor media than fungi with the host. The occurrence of a host only had a signicant
impact on the formation of the hyphal branch on poor medium. Further, a chlamydospore-like
structure was identied, which had a higher diameter when formed with the host on both rich and
poor media. The present data provide new insights into the host plant’s impact on the mycelial
features of ECM-forming fungi.
ARTICLE HISTORY
Received 10 November 2021
Accepted 25 April 2022
KEYWORDS
Ectomycorrhiza; host effect;
mycelial characters;
Rhizopogon roseolus
INTRODUCTION
Ectomycorrhizal (ECM) symbiosis has long been known
to provide various benefits for plants and their fungal
partners (Smith and Read 2008). The ECM fungi play an
essential role in the search for water and nutrients,
thereby supporting the growth and development of
their host plants (Smith and Read 2008; Tibbett and
Sanders 2002). Ectomycorrhizal symbiosis affects the
characters of host plant organs, such as changes in the
morphology and physiology of plant roots (Martin and
Hilbert 1991; Smith and Read 2008). Conversely, the
impact of host plants on the morphological character-
istics of the mycelia of ECM fungi has rarely been
reported. In addition, most prior studies sought to quan-
tify and characterize mycorrhizal fungi primarily from
arbuscular mycorrhizae (Declerck et al. 2004; De La
Providencia et al. 2005; Giovannetti et al. 2004).
Morphological characterization and quantification of
mycelia are essential to obtain a better biological under-
standing of mycelial response to ectomycorrhizal sym-
biosis and its cultivation aspects (Shimomura et al.
2012a). The morphological parameters that are com-
monly considered in assessment of mycorrhiza-
forming fungi include hyphal growth, hyphal length,
hyphal anastomosis, and the number of branches near
the hyphal tips (Declerck et al. 2004; De La Providencia
et al. 2005; De Novais et al. 2013; Giovannetti et al. 2004;
Sbrana et al. 2007, 2020). However, prior reports on
those aspects of ECM fungi are scarce both in situ and
in vitro. In addition, the effect of the host on mycor-
rhizal fungi has only been reported at a higher biological
level, where alterations occurred in the scope of the
community trophic structure in arbuscular mycorrhizae
(Eom et al. 2000) and ectomycorrhizae (Hoeksema et al.
2018). The impact of host plants on mycelial features of
ECM fungi has never been reported and thus warrants
the assessment.
The hyphae of ECM fungi are the most poorly under-
stood component of a symbiosis (Anderson and Cairney
2007; Cairney 2005; Staddon 2003). Chen et al. (2013)
revealed that an assessment of hypha production is
impractical to execute in the field. Hence, to understand
the mycelial response to host occurrence or absence, an
CONTACT Norihiro Shimomura nshimo@tottori-u.ac.jp
MYCOLOGIA
2022, VOL. 114, NO. 4, 670–681
https://doi.org/10.1080/00275514.2022.2071119
© 2022 The Mycological Society of America
Published online 09 Jun 2022
ResearchGate has not been able to resolve any citations for this publication.
HyLength: a semi-automated digital image analysis tool for measuring the length of roots and fungal hyphae of dense mycelia
Article
Full-text available
  • May 2020
  • MYCORRHIZA
In plant-fungus phenotyping, determining fungal hyphal and plant root lengths by digital image analysis can reduce labour and increase data reproducibility. However, the degree of software sophistication is often prohibitive and manual measuring is still used, despite being very time-consuming. We developed the HyLength tool for measuring the lengths of hyphae and roots in in vivo and in vitro systems. The HyLength was successfully validated against manual measures of roots and fungal hyphae obtained from all systems. Compared with manual methods, the HyLength underestimated Medicago sativa roots in the in vivo system and Rhizophagus irregularis hyphae in the in vitro system by about 12 cm per m and allowed to save about 1 h for a single experimental unit. As regards hyphae of R. irregularis in the in vivo system, the HyLength overestimated the length by about 21 cm per m compared with manual measures, but time saving was up to 20.5 h per single experimental unit. Finally, with hyphae of Aspergillus oryzae, the underestimation was about 8 cm per m with a time saving of about 10 min for a single germinating spore. By benchmarking the HyLength against the AnaMorf plugin of the ImageJ/Fiji, we found that the HyLength performed better for dense fungal hyphae, also strongly reducing the measuring time. The HyLength can allow measuring the length over a whole experimental unit, eliminating the error due to sub-area selection by the user and allowing processing a high number of samples. Therefore, we propose the HyLength as a useful freeware tool for measuring fungal hyphae of dense mycelia.
View
Hyphal network whole field imaging allows for accurate estimation of anastomosis rates and branching dynamics of the filamentous fungus Podospora anserina
Article
Full-text available
  • Feb 2020
The success of filamentous fungi in colonizing most natural environments can be largely attributed to their ability to form an expanding interconnected network, the mycelium, or thallus, constituted by a collection of hyphal apexes in motion producing hyphae and subject to branching and fusion. In this work, we characterize the hyphal network expansion and the structure of the fungus Podospora anserina under controlled culture conditions. To this end, temporal series of pictures of the network dynamics are produced, starting from germinating ascospores and ending when the network reaches a few centimeters width, with a typical image resolution of several micrometers. The completely automated image reconstruction steps allow an easy post-processing and a quantitative analysis of the dynamics. The main features of the evolution of the hyphal network, such as the total length L of the mycelium, the number of “nodes” (or crossing points) N and the number of apexes A, can then be precisely quantified. Beyond these main features, the determination of the distribution of the intra-thallus surfaces (Si) and the statistical analysis of some local measures of N, A and L give new insights on the dynamics of expanding fungal networks. Based on these results, we now aim at developing robust and versatile discrete/continuous mathematical models to further understand the key mechanisms driving the development of the fungus thallus.
View
Pulsatilla patens (Ranunculaceae), a perennial herb, is ectomycorrhizal in northeastern Poland and likely shares ectomycorrhizal fungi with Pinus sylvestris
Article
Full-text available
  • Mar 2018
  • ACTA SOC BOT POL
The sharing of species of ectomycorrhizal fungi (EMF) among different co-occurring host plant species could allow the formation of common mycorrhizal networks, which can alter plant–plant interactions and succession. Such sharing of EMF among woody species is thought to be common in many forests, but very few herbaceous plants form EMF, so they are assumed to be excluded from EMF networks in forests. We studied the EMF on roots of a common coniferous tree, Pinus sylvestris , and a co-occurring rare herbaceous perennial plant, Pulsatilla patens (Ranunculaceae), in northeastern Poland. We examined roots from co-occuring P. sylvestris and P. patens , visually classified EMF into morphotypes, studied tissue sections of mycorrhizal structures using compound microscopy, and used DNA sequencing to identify the fungi. On both host plant species, we observed EMF colonization, with colonized root tips exhibiting a swollen appearance, as well as a variety of colors and textures of fungal mycelium covering and emanating from those swollen tips. Sectioning and microscopic examination of an EMF morphotype common on P. patens confirmed the presence of a mantle and Hartig net, indicating the likely presence of functional ectomycorrhizal structures. The two most frequent EMF were Cenococcum geophilum and Piloderma olivaceum , and the latter was found to associate with both host plant species. Several EMF found here only on P. patens , including C. geophilum and two Russula species, are known from previous studies to also associate with P. sylvestris and other tree species. The observation of shared EMF between a coniferous tree and an understory herb indicates the potential for common mycorrhizal networks to alter interactions between these two species and may also indicate a unique way in which the distribution and abundance of a rare herbaceous plant may be influenced by shared mutualisms with a common co-occurring woody plant.
View
Testing sampling effort and relative abundance descriptors of belowground ectomycorrhizal fungi in a UK planted scots pine woodland
Article
Full-text available
  • Nov 2017
The native Caledonian pinewoods of Scotland, UK contain a unique and unexplored biodiversity of below-ground ectomycorrhizal fungi which may constitute a valuable source of microbial genetics resources for woodland restoration. In this study we test the sampling effort, taxa detection (ectomycorrhiza morpho-anatotyping) and relative abundance measurements (ectomycorrhizal root tip number vs. dry weight) of below-ground ectomycorrhizal fungal communities in a planted Pinus sylvestris Caledonian woodland. A total of 18 replicated sampling points were set up at differential distance along a 125 m transect, in a 50-yr-old, stem exclusion: thicket phase, Pinus sylvestris pinewood stand. A total of 11 ectomycorrhizal morpho-anatotypes were detected from 6689 ectomycorrhizal root tips counted and weighing 992.6 mg dry weight. The major ectomycorrhizal taxa were Meliniomyces bicolor and Cortinarius spp. accounting ~50% of total pine roots. A highly significant relationship (r2 = 0.16, p < 0.000) was found between Sørensen dissimilarity in soil cores and distance apart. In this study, the spatial arrangement of samples indicated that over short distances the dissimilarity was lower in contrast with the longer distances along the transect.
View
Comparison of radial growth rate of the mutualistic fungus of Atta sexdens rubropilosa forel in two culture media
Article
Full-text available
  • Jun 2010
In vitro culture of the mutualistic fungus of leaf-cutting ants is troublesome due to its low growth rate, which leads to storage problems and contaminants accumulation. This paper aims at comparing the radial growth rate of the mutualistic fungus of Atta sexdens rubropilosa Forel in two different culture media (Pagnocca B and MEA LP). Although total MEA LP radial growth was greater all along the bioassay, no significant difference was detected between growth efficiencies of the two media. Previous evidences of low growth rate for this fungus were confirmed. Since these data cannot point greater efficiency of one culture medium over the other, MEA LP medium is indicated for in vitro studies with this mutualistic fungus due its simpler composition and translucent color, making the analysis easier.
View
Root morphology and mycorrhizal symbioses together shape nutrient foraging strategies of temperate trees
Article
Full-text available
  • Jul 2016
Photosynthesis by leaves and acquisition of water and minerals by roots are required for plant growth, which is a key component of many ecosystem functions. Although the role of leaf functional traits in photosynthesis is generally well understood, the relationship of root functional traits to nutrient uptake is not. In particular, predictions of nutrient acquisition strategies from specific root traits are often vague. Roots of nearly all plants cooperate with mycorrhizal fungi in nutrient acquisition. Most tree species form symbioses with either arbuscular mycorrhizal (AM) or ectomycorrhizal (EM) fungi. Nutrients are distributed heterogeneously in the soil, and nutrient-rich “hotspots” can be a key source for plants. Thus, predicting the foraging strategies that enable mycorrhizal root systems to exploit these hotspots can be critical to the understanding of plant nutrition and ecosystem carbon and nutrient cycling. Here, we show that in 13 sympatric temperate tree species, when nutrient availability is patchy, thinner root species alter their foraging to exploit patches, whereas thicker root species do not. Moreover, there appear to be two distinct pathways by which thinner root tree species enhance foraging in nutrient-rich patches: AM trees produce more roots, whereas EM trees produce more mycorrhizal fungal hyphae. Our results indicate that strategies of nutrient foraging are complementary among tree species with contrasting mycorrhiza types and root morphologies, and that predictable relationships between below-ground traits and nutrient acquisition emerge only when both roots and mycorrhizal fungi are considered together.
View
Different levels of hyphal self-incompatibility modulate interconnectedness of mycorrhizal networks in three arbuscular mycorrhizal fungi within the Glomeraceae
Article
Full-text available
  • May 2016
  • MYCORRHIZA
Arbuscular mycorrhizal fungi (AMF) live in symbiosis with most plant species and produce underground extraradical hyphal networks functional in the uptake and translocation of mineral nutrients from the soil to host plants. This work investigated whether fungal genotype can affect patterns of interconnections and structural traits of extraradical mycelium (ERM), by comparing three Glomeraceae species growing in symbiosis with five plant hosts. An isolate of Funneliformis coronatus consistently showed low ability to form interconnected ERM and self-incompatibility that represented up to 21 % of hyphal contacts. The frequency of post-fusion self-incompatible interactions, never detected before in AMF extraradical networks, was 8.9 %. In F. coronatus ERM, the percentage of hyphal contacts leading to perfect hyphal fusions was 1.2-7.7, while it ranged from 25.8-48 to 35.6-53.6 in Rhizophagus intraradices and Funneliformis mosseae, respectively. Low interconnectedness of F. coronatus ERM resulted also from a very high number of non-interacting contacts (83.2 %). Such findings show that AMF genotypes in Glomeraceae can differ significantly in anastomosis behaviour and that ERM interconnectedness is modulated by the fungal symbiont, as F. coronatus consistently formed poorly interconnected networks when growing in symbiosis with five different host plants and in the asymbiotic stage. Structural traits, such as extent, density and hyphal self-compatibility/incompatibility, may represent key factors for the differential performance of AMF, by affecting fungal absorbing surface and foraging ability and thus nutrient flow from soil to host roots.
View
A Whole-Plant Culture Method to Study Structural and Functional Traits of Extraradical Mycelium
Chapter
  • May 2020
An in vivo whole-plant bi-dimensional experimental system has been devised and tested with different host plants, in order to obtain extraradical mycelium (ERM) produced by different arbuscular mycorrhizal fungi (AMF). In this system, a host plant germling is inoculated with AMF to establish mycorrhizal symbiosis, and, after colonization, newly formed extraradical hyphae and spores are removed. Then the mycorrhizal root system is wrapped in a nylon net and placed between membranes in a Petri dish, allowing ERM to grow on the membrane surface. Such extraradical hyphae may be used for in situ morphometric analyses or collected for molecular or biochemical assays: in the latter case, the plant with its root sandwich may be reassembled to renew mycelium production. In this experimental system, which was tested with diverse host plant species and lines, values of explored membrane surface areas and densities of ERM showed wide ranges of variation, and its length ranged from 9.7 ± 2.0 to 48.8 ± 9.9 m per plant, depending on host and AMF identity. Across the different plant-AMF combinations tested, the whole-plant system produced 2.0 ± 0.6 to 5.3 ± 0.3 mg of ERM fresh biomass per plant per harvest. This experimental system can be used for a wide range of AMF and host plants species, either establishing arbuscular mycorrhizas or other mycorrhizal interactions. ERM produced and collected in the whole-plant system is suitable for morphological, physiological, and molecular analyses, facilitating studies on the different aspects of mycorrhizal symbiotic interactions.
View
Mycorrhizal Symbiosis
Book
  • Jan 2008
The roots of most plants are colonized by symbiotic fungi to form mycorrhiza, which play a critical role in the capture of nutrients from the soil and therefore in plant nutrition. Mycorrhizal Symbiosis is recognized as the definitive work in this area. Since the last edition was published there have been major advances in the field, particularly in the area of molecular biology, and the new edition has been fully revised and updated to incorporate these exciting new developments. . Over 50% new material . Includes expanded color plate section . Covers all aspects of mycorrhiza . Presents new taxonomy . Discusses the impact of proteomics and genomics on research in this area.
View
Foraging for Resources in Arbuscular Mycorrhizal Fungi: What is an Obligate Symbiont Searching for and How is it Done?
Chapter
  • Jan 2008
This chapter presents first a brief summary of basic concepts about foraging and foraging theory derived from studies in animals and applied later to the search of resources in plants and fungi. Efficiency in the search and acquisition of resources is an important component of fitness in the plant and the fungal partner, and a fundamental contributor for a successful mutualistic symbiosis, but foraging is still a neglected area in mycorrhizal research. Arbuscular mycorrhizal fungi are obligate symbionts that obtain all their carbon from the plant they colonise but have to find other resources through soil exploration. The search is therefore constrained by this carbon dependency and recent discoveries about their growth and physiology have important implications on our understanding of foraging capacities, limits and strategies in these organisms. Also, an overview of the results of some experiments testing hypotheses and models presented in a previous review on foraging activities, resource allocation and responsiveness to enriched patches with different resources is provided. Two models, a two-dimensional and a multidimensional, have been used for those tests and are discussed but the information available is still too scarce to suggest general patterns of foraging in arbuscular mycorrhizal fungi. Finally, there is an evaluation of new directions, promising approaches and methodological developments for further research on this topic.
View