Effects of temperature, pH and carbon and nitrogen sources on growth of in vitro cultures of ectomycorrhizal isolates from Pinus heldreichii forest

Abstract

Aim of study: This study aims to provide basic information about physiological characteristics of isolates of Lactarius deliciosus (L.) Gray, Russula sanguinaria (Schumach.) Rauschert, Suillus collinitus (Fr) Kuntze, Suillus granulatus (L.) Rousell, Tricholoma batchii Gulden and Tricholoma imbricatum (Fr.) Kumm.Area of study: The isolates are obtained from Pinus heldreichii H. Christ forest in the south-eastern part of Montenegro. Material and methods:The isolates were molecularly characterised by internal transcribed spacer (ITS) sequencing and restriction fragment length polymorphism (RFLP) analysis. The effects of different temperatures (20, 22, 25°C), pHs (4, 4.5, 5.2, 5.8, 6.5, 7.5), and carbon (glucose, sucrose, dextrin, arabinose, xylose and starch) and nitrogen (NH 4 + , NO 3 -and protein) sources on their growth were examined under laboratory conditions.Main results: The studied factors established significant differences in the development of isolates. Isolates of R. sanguinaria, L. deliciosus and both Suillus, were characterised by faster growth at 22°C, while Tricholoma isolates grew faster at 25°C. S. granulatus, S. collinitus and T. imbticatum isolates grew well at lower pH values (4 -5.2), while L. deliciosus, R. sanguinaria and T. bachii exhibited faster growth at pHs between 5.8 and 6.5. The examined isolates were able to utilize various carbohydrates as carbon sources. The biggest mycelial growth was characterised for sucrose, then glucose, dextrin, arabinose, starch and xylose. They grew on all examined nitrogen sources, while the biggest mycelia growth was achieved on ammonium, followed by nitrate and protein. Those characteristics varied amongst the species.Research highlights: Information about physiological characteristics of Tricholoma, Lactarius, Russula, as well as Suillus, are sparse. Hence, the data obtained in this study could contribute to the understanding of their function in ecosystems.Keywords: Lactarius; Montenegro; physiology; RFLP analysis; Russula; Suillus; Tricholoma. Citation: Lazarević, J., Stojičić, D., Keča, N. (2016). Effects of temperature, pH and carbon and nitrogen sources on growth of in vitro cultures of ectomycorrrhizal isolates from Pinus heldreichii forest. Forest Systems, Volume 25, Issue 1, e048. http://dx.doi.

In vitro GROWTH OF ECTOMYCORRHIZAL FUNGI ASSOCIATED WITH Pinus radiata PLANTATIONS IN CHILE

“…The results showed that, in general, R. luteolus tends to grow better under acidic than alkaline conditions. This finding agrees with the trends mentioned by Hung and Trappe (1983), Lazarević et al (2016) and Willenborg et al (1990), who mentioned that ECMF have in general, an acidophilic nature when grown under pure culture conditions. However, it is important to mention that there are some exceptions either specific or intraspecific, i.e.…”

“…Some studies have shown that the ectomycorrhizal mycelium might be very sensitive to temperature variations (Lazarević et al, 2016;Marx et al, 1970;Sánchez et al, 2001). If the soil dramatically cools, the metabolic activity of the fungi and the roots decrease, with negative consequences for mycelial growth and nutrient availability for both the fungi and the associated plants (Lazarević et al, 2016).…”

“…Dennis (1985) reported optimal growth for S. granulatus at 25 ºC and for S. luteus in the interval of 20 to 25 ºC. Lazarević et al (2016) recorded the best growth for S. collinitus and S. granulatus at 22 ºC. Cline et al (1987) reported the best growth for S. granulatus at 27 ºC, and for Suillus spp.…”

“…Culture conditions tested. In the first experiment, the evaluated temperatures were 24, 28 and 32 ºC (Andrino et al, 2011;Arana-Gabriel et al, 2014;Bran et al, 2015;Lazarević et al, 2016). From growing active colonies (stock cultures), 5 mm diameter agar-mycelial discs were transferred to 90 mm diameter Petri dishes containing 20 mL of agar Modified Melin Norkrans (MMN) as a culture medium, with a pH adjusted to 5.8.…”

“…Growth differences of ECMF under in vitro conditions have been considered a guide for prescreening potential fungal species (strains or ecotypes) to be used in nursery mycorrhization programs. In the present study, the biomass production in different in vitro conditions was analyzed in order to understand the optimal temperature and pH conditions for the evaluated ECMF (Eng et al, 2003;Lazarević et al, 2016;Pereira et al, 2007;Sánchez et al, 2001). The objective of the present study was to analyze the effect of three temperatures and five different pH levels on the in vitro growth of the species of ECMF R. luteolus, S. granulatus and S. luteus naturally associated with Pinus radiata plantations growing at low productivity sites in Chile, assuming that each strain or ecotype has its own ecological optimal conditions.…”