Effect of earthworms on mycorrhization, root morphology and biomass of silver fir seedlings inoculated with black summer truffle (Tuber aestivum Vittad.)

Abstract

Species of the genus Tuber have gained a lot of attention in recent decades due to their aromatic hypogenous fruitbodies, which can bring high prices on the market. The tendency in truffle production is to infect oak, hazel, beech, etc. in greenhouse conditions. We aimed to show whether silver fir (Abies alba Mill.) can be an appropriate host partner for commercial mycorrhization with truffles, and how earthworms in the inoculation substrate would affect the mycorrhization dynamics. Silver fir seedlings inoculated with Tuber. aestivum were analyzed for root system parameters and mycorrhization, how earthworms affect the bare root system, and if mycorrhization parameters change when earthworms are added to the inoculation substrate. Seedlings were analyzed 6 and 12 months after spore inoculation. Mycorrhization with or without earthworms revealed contrasting effects on fine root biomass and morphology of silver fir seedlings. Only a few of the assessed fine root parameters showed statistically significant response, namely higher fine root biomass and fine root tip density in inoculated seedlings without earthworms 6 months after inoculation, lower fine root tip density when earthworms were added, the specific root tip density increased in inoculated seedlings without earthworms 12 months after inoculation, and general negative effect of earthworm on branching density. Silver fir was confirmed as a suitable host partner for commercial mycorrhization with truffles, with 6% and 35% mycorrhization 6 months after inoculation and between 36% and 55% mycorrhization 12 months after inoculation. The effect of earthworms on mycorrhization of silver fir with Tuber aestivum was positive only after 6 months of mycorrhization, while this effect disappeared and turned insignificantly negative after 12 months due to the secondary effect of grazing on ectomycorrhizal root tips.

Importance of soil amendments with biochar and/or Arbuscular Mycorrhizal fungi to mitigate aluminum toxicity in tamarind (Tamarindus indica L.) on an acidic soil: A greenhouse study

“…In another study, Nahberger et al. [ 76 ] showed that earthworms improved mycorrhization of silver fir with Tuber aestivum , and the effect was only significant after six months. According to them, the effect became insignificantly negative by the 12 months due to grazing of the root tips.…”

Buckwheat Milling Waste Effects on Root Morphology and Mycorrhization of Silver Fir Seedlings Inoculated with Black Summer Truffle (Tuber aestivum Vittad.)

“…Four-month-old, certified silver fir seedlings with a cover root system and that were morphologically uniform were purchased from the LIECO nursery (Kalwang, Austria) and were transferred to pots. The criteria for seedling quality were described in a previous study by Unuk Nahberger et al [17].…”

“…DNA extractions were performed with the DNeasy Plant mini kit (Qiagen, Hilden, Germany) following the manufacturer's instructions. Due to observed difficulties with the summer truffle ITS region amplification [17,19], the following fungus-specific primer pairs were used: ITS1f (5 -CTTGGTCATTTAGAGGAAGTAA-3 ) and ITS4 (5 -TCCGCTTARTGATARGC-3 ) [20,21]; and ITS5 (5 -GGAAGTAAAAGTCGTAACAAGG-3 ) and ITS7 (5 -ACTCGCCGTTACTGAGGCAAT-3 ) [22]. The PCR reactions involving the first pair, ITS1f/ITS4, were performed, as described by Grebenc and Kraigher [23], while the PCR reactions involving the second pair, ITS5/ITS7, were performed as described in [17].…”

Production and marketing of Tuber floridanum – ecology and gastronomic value of a recently described truffle species

“…All known truffle species are ectomycorrhizal (Rinaldi et al, 2008) or can form ectendomycorrhizal or endophytic relationships under specific conditions. Truffles form mycorrhiza with trees and shrubs and rarely interact with non-ectomycorrhizal plants in natural environments (Ori et al, 2020;Schneider-Maunoury et al, 2020;Nahberger et al, 2021). Besides vital mycorrhizal plant partners, most truffle species require specific soil conditions to prosper and fruit, such as neutral to alkaline pH (Hall et al, 2007;Ge et al, 2017), high concentration of available calcium, and low organic matter contents (Hall et al, 2007;Zambonelli et al, 2017).…”