Diversity of endophytic fungi of single Norway spruce needles and their role as pioneer decomposers

Abstract

The diversity of endophytic fungi within single symptomless Norway spruce needles is described and their possible role as pioneer decomposers after needle detachment is investigated. The majority (90%) of all 182 isolates from green intact needles were identified as Lophodermium piceae. Up to 34 isolates were obtained from single needles. Generally, all isolates within single needles had distinct randomly amplified microsatellite (RAMS) patterns. Single trees may thus contain a higher number of L. piceae individuals than the number of their needles. To investigate the ability of needle endophytes to act as pioneer decomposers, surface-sterilized needles were incubated on sterile sand inoculated with autoclaved or live spruce forest humus layer. The dry weight loss of 13-17% found in needles after a 20-week incubation did not significantly differ between the sterilized and live treatments. Hence, fungi surviving the surface sterilization of needles can act as pioneer decomposers. A considerable portion of the needles remained green during the incubation. Brown and black needles, in which the weight loss had presumably taken place, were invaded throughout by single haplotypes different from L. piceae. Instead, Tiarasporella parca, a less common needle endophyte, occurred among these invaders of brown needles. Needle endophytes of Norway spruce seem thus to have different abilities to decompose host tissues after needle cast. L. piceae is obviously not an important pioneer decomposer of Norway spruce needles. The diversity of fungal individuals drops sharply when needles start to decompose. Thus, in single needles the decomposing mycota is considerably less diverse than the endophytic mycota.

Transient leaf endophytes are the most active fungi in 1-year-old beech leaf litter

“…Previous studies suggested a lower overlap between fungi of leaves and litter and faster species turnover during early decomposition (Müller et al 2001;Osono 2006;Voríšková and Baldrian 2013;Szink et al 2016). These studies were mostly locally restricted, and agree largely with the conditions we observed for single plots.…”

Aerobic carbon-cycle related microbial communities in boreal peatlands: responses to water-level drawdown

“…Phyllosphere fungi might contain primary saprotrophs (Hudson 1968) that readily utilize carbohydrates and generate a more favourable environment for the colonization of fungi capable of decomposing more recalcitrant substances. Müller et al (2001) found that endophytic fungi act as pioneer decomposers in surface-sterilized spruce needles when incubated for 5 months on sterile and non-sterile soils. Furthermore, endophytic fungi were an active part of the needle-decay community during the entire two-year decomposition study (Korkama-Rajala et al 2007).…”

Class III endophytes, clandestine movement amongst hosts and habitats and their potential for disease; a focus on Neofusicoccum australe

“…The genetic diversity reflected within each site could be attributed to the lifestyle of endophytic Botryosphaeriaceae. As Class III endophytes they inhabit small localised pockets of their host (Müller et al 2001;Rodriguez et al 2009) and multiple genotypes can be found within a single host (Müller et al 2001). Therefore amongst numerous hosts the overall genetic diversity would be expected to be high.…”