Fungi associated with Copaifera oblongifolia (Fabaceae) seeds: occurrence and possible effects on seed germination

Abstract

Copaifera oblongifolia is a recurrent plant species in degraded areas yet there is little information about its seed biology and interactions with fungi. The aims of this study were to identify the fungal community (endophytic and nonendophytic) associated with C. oblongifolia seeds and to test the effects of these different fungal species on germination. In general, germination of C. oblongifolia seeds was high (about 85 %), initiating four days after sowing and continuing for a total of 20 days. External asepsis with sodium hypochlorite did not influence germinability of C. oblongifolia. Seed infestation with Aspergillus niger, A. flavus, Mucor sp. and Rhizopus stolonifer did not affect the time required for germination, however, infection with A. flavus negatively affected germination percentage. Endophytic fungi were not isolated from C. oblongifolia seeds, suggesting that this species does not transmit endophytic fungi vertically. Therefore, C. oblongifolia can be classified in Class 3 with regard to the transmission and presence of endophytes.

Filtrates from cultures of endophytic fungi isolated from leaves of Copaifera oblongifolia (Fabaceae) affect germination and seedling development differently

“…EFs found in the leaves of tropical pioneer plants are, in general, generalists and can negatively affect seed germination and seedling development (Kluger et al, 2008). Copaifera oblongifolia is a tropical shrub invader of habitats in the initial stage of succession and does not have EFs associated with its seeds (Fernandes et al, 2019). Therefore, the fungi found in the leaves of C. Oblongifolia example, the species D. helianthi, D. heveae, N. parvum, P. prosopidis and Phomopsis sp.…”

“…Several studies have shown that EFs can inhibit (Jiang et al, 2008;Meepagala et al, 2016;Mazarotto et al, 2019), stimulate (Tudzynski and Sharon, 2002;Gallery et al, 2007;Khan et al, 2017) or not affect (Fernandes et al, 2019) the seed germination of different plant species. Germination inhibition can occur through the production of phytoinhibitors (Meepagala et al, 2016;Khiralla et al, 2018) or simply through the degradation of seed reserves, causing starvation and death of the embryo (Dhingra et al, 2002;Fagundes et al, 2013).…”

“…Seeds are structures that are rich in carbohydrates, proteins and minerals (Nelson, 2004;Fenner and Thompson, 2005;Bewley et al, 2013), and can be colonized by a diverse array of microorganisms, including EFs, that can be pathogenic or beneficial for seeds (Nelson, 2004;Fernandes et al, 2019). Some EFs are also capable of producing cellulase that degrades the husks of seeds, thereby accelerating seed inhibition and embryo development (Delgado-Sánchez et al, 2011, 2013.…”

“…Some species of fungi can inhibit germination by producing phytotoxins that affect the triggering metabolic processes (Halloin, 1986;Khiralla et al, 2018), or simply degrade the seeds causing the embryo to die (Fagundes et al, 2011). However, seed-EFs relationships are still poorly understood and may be species-dependent (Qin et al, 2016;Geisen et al, 2017;Fernandes et al, 2019). In addition, EFs found in the leaves of some plant species can inhibit three mature leaves were removed from each branch and washed thoroughly under running water to remove dust particles from the surface.…”

“…In contrast, smaller seeds germinate more quickly and invest proportionately more resources in root development, and thus are favored in transient habitats. Therefore, seed germination is a critical stage in the life cycle of plants, being influenced by several abiotic factors such as light, temperature and humidity (Veloso et al, 2017;Fagundes et al, 2020) and biotic factors such as predators and parasitic or mutualistic microorganisms (Moles and Westoby, 2006;Farias et al, 2015;Fernandes et al, 2019).…”