Endomycorrhizal association ofFunneliformis mosseaewith transformed roots ofLinum usitatissimum: germination, colonization, and sporulation studies

Abstract

Spores of arbuscular mycorrhizal (AM) fungus Funneliformis mosseae (Nicolson & Gerdemann) Walker & Schuessler were cultured in association with transformed roots of Linum usitatissimum L. (Linaceae) for the first time on modified Strullu–Romand medium (pH 5.5) in monoxenic culture. Germ tubes emerged through the spore wall in 88% of spores after 5 days. Hyphal contact with transformed linum roots was observed 5 days after co-cultivation. Paris-type arbuscules and hyphal coils were seen. Extra-radical branched absorbing structures were common. Terminal and intercalary secondary spores were also formed. Spore viability when assessed using vital dye staining (MTT test) was 83%. Secondary spores that proved viable were subsequently transferred from in vitro to in vivo culture where Arum-type arbuscules, intra-radical intercellular hyphae, and extra-radical spores were observed. The procedure established shows potential in AM inoculum mass production and possibility in application.

RocTest: A standardized method to assess the performance of root organ cultures in the propagation of arbuscular mycorrhizal fungi

“…Carrot roots show a consistent and vigourous growth ( Bécard and Fortin, 1988 ) and support an abundant production of spores when inoculated with some Rhizophagus species ( St-Arnaud et al, 1996 ; Douds, 2002 ; Rosikiewicz et al, 2017 ). Root organs from other plant species are also used to propagate AMF, such as Cichorium intybus ( Verdin et al, 2006 ), Glycine max ( Fernandez et al, 2009 ), Linum usitatissimum ( Rodrigues and Rodrigues, 2015 ), Lycopersicon esculentum ( Simoneau et al, 1994 ), Medicago truncatula ( Boisson-Dernier et al, 2001 ) or Solanum tuberosum ( Angelard et al, 2014 ). There is currently no tool to assess their performance against each other or against the carrot root organs commonly used in germplasms.…”

“…The identification of the best pairing is a reasonable goal toward increasing the diversity and stability of AM monoxenic cultures. About 20 AMF species have been established on ROCs ( Rodrigues and Rodrigues, 2015 ), but their propagation over multiple generations is not guaranteed, as the fungi can stop growing after a few subcultures. Thus, fewer than 10 of 343 known AM species 1 are perpetually maintained under in vitro conditions in international collections (Mycothèque de L’UCLouvain-Belgian Co-ordinated Collections of Microorganisms – BCCM /MUCL 2 , Canadian Collection of AMF – CCAMF 3 .…”