Mycorrhizal association in gametophytes and sporophytes of the fern <i>Pteris vittata</i> (Pteridaceae) with <i>Glomus intraradices</i>

Abstract

Ferns, which are usually colonizing different environments and their roots frequently present mycorrhization, have two adult stages in their life cycle, the sporophytic and the gametophytic phase. This paper describes the experimental mycorrhizal association between Pteris vittata leptosporangiate fern and a strain of Glomus intraradices during the life cycle of the fern, from spore germination to the development of a mature sporophyte. The aim of this study was to compare the colonization pattern of in vitro cultures of G. intraradices along the fern life cycle with those found in nature. For this, mature spores were obtained from fertile P. vittata fronds growing in walls of Buenos Aires city, Argentina. Roots were stained and observed under the light microscope for arbuscular mycorrhizal colonization. Approximately, 75 fern spores were cultured in each pot filled with a sterile substrate and G. intraradices (BAFC N° 51.331) as inoculum on the surface. After germination took place, samples were taken every 15 days until the fern cycle was completed. In order to determine colonization dynamics each sample was observed under optical and confocal microscope after staining. Gametophyte was classified as Adiantum type. Male and female gametangia were limited to the lower face, mycorrhizal colonization started when they were differentiated and took place through the rhizoids. Spores and vesicles were not found in this cycle stage. Paris-type mycorrhizal colonization was established in the midrib and in the embrionary foot. It was colonized by external mycelium. When the first root was developed soil inoculum colonized de novo this structure and Arum-type colonization was observed. This study proves that the type of colonization is determined by the structure of the host, not by the fungus. Both the gametophyte and embryo foot have determined growth and Paris-type colonization, while, sporophyte roots have undetermined growth and Arum-type colonization. The structures found in vitro cultures were highly similar to those found under natural conditions. Rev. Biol. Trop. 60 (2): 857-865. Epub 2012 June 01.Key words: Pteris vittata, Glomus intraradices, Pteridophyta-gametophyte-sporophyte, Arum colonization, Paris colonization.Over 90% of terrestrial plant groups have some type of symbiosis with soil fungi, and/or some mycorrhizal form. During the Devonic period, the first plants with roots appeared on land, the ferns belonging to Pteridophyta, Filicales groups, still exist today. They are widely distributed, particularly in tropical environments, and many of them have roots colonized by arbuscular mycorrhizal fungi (AM) (Brundrett 2002). Fern species with fine roots and long absorbent hairs sometimes limit mycorrhizal colonization. This facultative association is considered to be a feature of more evolved ferns (Fernandez et al. 2010). Cairney (2000 and Brundrett (2002) suggested that mycorrhizal symbiosis probably enabled plants to colonize land, conferring advantages such as increased fitness and resistance ...

Micorriza arbuscular, Mucoromycotina y hongos septados oscuros en helechos y licófitas con distribución en México: una revisión global

“…Las especies con mayor número de muestras fueron Pteris vittata L. con 12 registros, Pteridium aquilinum (L.) Kuhn in v. d. Decken con nueve, Adiantum capillus-veneris L. con ocho, Botrychium virginianum (L.) Sw. con seis, Pteris cretica L. y Psilotum nudum (L.) , 2009, Dhillion, 1993, Fernández, Messuti, & Fontenla, 2013, Gemma et al, 1992, Hepden, 1960, Iqbal, Yousaf, & Younus, 1981, Kessler et al, 2014, Khade & Rodrigues, 2002, Kovács, Kottke, & Oberwinkler, 2003, Kovács, Balazs, & Penzes, 2007, Laferrière & Koske, 1981, Lara-Pérez et al, 2014, Lara-Pérez, 2007, Lara-Pérez, 2015, Laursen, Treu, Seppelt, & Stephenson, 1997, Lee, Eom, Lee, & Lee, 2001, Lesica & Antibus, 1990, Leung, Ye, & Wong, 2007, Liu, Zhu, Chen, Christie, & Li, 2005, Martínez, Chiocchio, Em, Rodríguez, & Godeas 2012, Mishra, Sharma, & Gatphoh, 1980, Moteetee, Duckett, & Russell, 1996, Muthukumar, Sathiyaraj, Priyadharsini, Uma, & Sathiyadash, 2014, Muthukumar & Prabha 2012, Muthukumar & Prabha 2013, Muthuraja, Muthukumar, Sathiyadash, Uma, & Priyadharsini, 2014, Nadarajah & Nawawi, 1993, Palmieri & Swatzell, 2004, Reyes-Jaramillo et al, 2008, Santhoshkumar & Nagarajan 2014, Schmid & Oberwinkler, 1996, Schmid, Oberwinkler, & Gómez, 1995, Schmid & Oberwinkler, 1993…”

Pteridophyte fungal associations: Current knowledge and future perspectives

“…In addition to Glomeraceae, they also found members of the Claroideoglomeraceae, Gigasporaceae, Acaulosporaceae, and Archaeosporales fungi previously unknown in ferns but which are widespread in thalloid liverworts and hornworts (Bidartondo et al, ; Desirò et al, ; Field et al, 2015b). There is now a pressing need to extend these molecular studies to Polypodiales since recent light microscope studies indicate the presence of similar associations in a range of genera; Adiantum, Pellaea (Turnau et al, ), Dryopteris (Reyes‐Jaramillo et al, ), Nephrolepis (Muthukumar & Prabia, 2012) and Pteris (Martinez et al, ), and particularly since the discovery of both Glomeromycota (Glomeraceae and Diversisporaceae) and Mucororomycotina in Anogramma leptophylla from the only fungal DNA sequencing study to date on the sporophytes of a member of the Polypodiales (Figs. c, 2d) (Rimington et al, ).…”

“…Thus, they would appear to be highly suitable material for investigations into the effects of the fungi on the hosts. Such studies have yet to be attempted; however, a recent paper by Martinez et al () clearly demonstrates their feasibility. When grown on a substrate inoculated with Rhizophagus irregularis, gametophytes of Pteris vittata displayed Paris‐ type recolonization whilst the roots had Arum‐ type colonisation.…”

Plant evolution driven by interactions with symbiotic and pathogenic microbes

“…We presume that this state followed intercellular or surface interactions that likely represent intermediate stages in the formation of intracellular symbiosis. Depending on the tissue where the intermediate intercellular symbiosis occurs, transition toward intracellular infection will utilize different cell types such as rhizoids or atrichoblasts, possibly in a generationdependent manner (100). Such transitions might be ongoing in the extant plant -cyanobacteria symbiosis.…”