LettersFine endophytes (Glomus tenue) are related to Mucoromycotina, not GlomeromycotaFine endophytes are arbuscule-producing fungi of unclear phylogenetic placement Fine endophytes (FE), Glomus tenue, are traditionally considered to be arbuscular mycorrhizal fungi (AMF) with distinctive microscopic morphology when stained. FE have fine hyphae (c. 1.5 lm diameter) which branch intra-cellularly in a distinctive fan-like pattern (Gianinazzi-Pearson et al., 1981;Abbott, 1982). The hyphae contain small swellings along their length, sometimes referred to as vesicle-like swellings (Hall, 1977). FE form arbuscules (or arbuscule-like structures) with fine elements in a tapered, conical shape (Greenall, 1963;Merryweather & Fitter, 1998). Spores of FE are very small (< 20 lm) compared to the majority of Glomeromycota, and colourless (Hall, 1977). Morphological variations indicate that FE may consist of multiple species (Thippayarugs et al., 1999), hence we use the term FE to indicate a species group.Within the kingdom Fungi, both morphological and genetic characteristics are used to determine taxonomic classification (St€ urmer, 2012). In 2001, all AMF were placed within the phylum Glomeromycota (Sch€ ußler et al., 2001). In the listing of glomeromycotan species by Sch€ ußler & Walker (2010), some members of the genus Glomus were not revised due to insufficient taxonomic knowledge, and this included FE. A key reason for classifying FE within the Glomeromycota was the presence of arbuscules, considered apomorphic for the phylum (Morton, 1990). However, the morphological features of root colonization by FE are distinct from other, coarse, AMF so their placement within the genus Glomus and the Glomeromycota was questioned (Hall, 1977;Sch€ ußler & Walker, 2010), and their status as mycorrhizal fungi is ambivalent.Accurate determination of FE usually requires magnification ≥ 9100, hence, where assessments of AMF colonization use lower magnifications they may not be identified. Furthermore, FE may be undetected if samples are not processed within 2 d of harvesting (Orchard et al., 2016a). Nevertheless, FE are globally distributed and prolific within many ecosystems, examples include: pastures and native bushland of New Zealand (Crush, 1973) and Australia (Abbott & Robson, 1982;McGee, 1989), Venezuelan cloud forests (Rabatin et al., 1993), riverine and alpine regions of Europe (Read & Haselwandter, 1981;Turnau et al., 1999;Binet et al., 2011) and an old-field in the United States (Hilbig & Allen, 2015). However, the difficulty of isolating and, hence, genetically characterizing FE has hindered the determination of their phylogenetic placement. A novel method to enrich colonization by fine endophytesTo clarify the identity of FE, we targeted the SSU (18S) ribosomal RNA gene using roots from two independent glasshouse experiments where individual pots contained multiple plants. For each pot we used one root system for DNA extraction and one root system to visually assess the percentage of total root length colonized (%TRL; see Sup...

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The role of plant endophytic Actinobacteria remains poorly understood with no reports of these communities in New Zealand native plants. This first investigation of endophytic Actinobacteria in New Zealand targeted the culturally significant medicinal shrub Pseudowintera colorata (horopito) as a model plant. Community analysis in plant tissues collected from ten geographically distinct sites showed that tissue type had the strongest influence on diversity and richness of endophytic Actinobacteria. More denaturing gradient gel electrophoresis (DGGE) bands were obtained from stems (n = 18) compared to roots (n = 13). Sequencing analysis of the major bands (n = 20) identified them as uncultured bacteria, Streptomyces sp. and Angustibacter peucedani. Using two Actinobacteria-specific media, nine isolates were recovered from surface-sterilised P. colorata tissues. This was approximately 12% of the total taxa and correlated well with culturable numbers in international studies. In vitro analysis of the functionality of these strains showed that Streptomyces sp. PRY2RB2 inhibited all the tested phytopathogenic fungi (n = 4), Streptomyces sp. UKCW/B and Nocardia sp. TP1BA1B solubilised phosphate and produced siderophores. The functionality of the phosphate solubilising strains (n = 2) in vivo was investigated by inoculation of P. colorata seedlings. After 4 months, the mean shoot height of seedlings treated with Nocardia sp. TP1BA1B was 1.65× longer, had higher shoot dry weight (1.6×) and number of internodes (1.67×) compared to control. This study identified for the first time a key group of endophytic Actinobacteria that are likely to be important in the ecology of New Zealand flora.

Leptospermum scoparium or mānuka is a New Zealand native medicinal plant that produces an essential oil with antimicrobial properties. This is the first study to investigate the structure and bioactivity of endophytic bacteria in mānuka by using a combination of cultivation-independent (DGGE) and dependent approaches. A total of 23 plants were sampled across three sites. Plants were considered either immature (3–8 years) or mature (>20 years). The endophyte community structure and richness was affected by plant tissue and bacterial communities became more stable and uniform as plant maturity increased. A total of 192 culturable bacteria were recovered from leaves, stems and roots. Some bacterial isolates showed in vitro biocontrol activity against two fungal pathogens, Ilyonectria liriodendri and Neofusicoccum luteum and a bacterial pathogen, Pseudomonas syringae pv. actinidiae. A high proportion of bacterial endophytes could produce siderophores and solubilise phosphate in vitro. Gammaproteobacteria was the most variable class, representing the majority of cultivated bacteria with bioactivity.