Lophodermium pinastri and an unknown species of Teratosphaeriaceae are associated with needle cast in a Pinus radiata selection trial

Abstract

Spring needle cast (SNC) in Tasmania is defined by the early casting of pine needles and appears in 6-to 7-year-old pine plantations after canopy closure. The severity of SNC can vary significantly among trees growing within the same plantation. Fungal communities were surveyed in a Pinus radiata family trial, using DNA extraction from needles, PCR with fungal-specific primers and sequencing to detect the presence of fungal species. Samples were taken at the same time as the trees were scored for disease severity. Trees with contrasting levels of SNC disease severity have significantly different needle fungal communities, but family pedigree and different ages of needle are not clearly distinguished by their fungal communities. All common fungal pathogens previously implicated in causing SNC were identified from the study, but of these, only Lophodermium pinastri was correlated with high levels of disease. Several species of Teratosphaeriaceae were detected, and one of these was also strongly associated with needle cast.

Needle fungi in young Tasmanian Pinus radiata plantations in relation to elevation and rainfall

“…Trees with contrasting levels of SNC disease severity were found to have significantly different needle fungal communities. The four fungi, L. pinastri, C. minus, S. geniculata and Dothistroma septosporum, previously reported as common pathogens or endophytes in P. radiata in Tasmania implicated in causing SNC (Podger 1984;Podger and Wardlaw 1990) were also identified in the Prihatini et al (2015a) study. Of these, only L. pinastri was correlated with high levels of disease.…”

“…After phylogenetic analysis, 70 ascomycetous OTUs were discriminated (Table 2), of which 36 were detected from more than one sample. Seventeen species of hitherto unknown members of the Teratosphaeriaceae were identified as part of the P. radiata marker-aided selection trial (Prihatini et al 2015a) run in parallel with the current study, and nine of these were also detected in the current study.…”

“…This was achieved with the identification of 70 distinct OTUs. A number of these species were also found as part of the P. radiata marker-aided selection trial (Prihatini et al 2015a) run in parallel with the current study, including some members of the Teratosphaeriaceae. However, there is some doubt about the taxonomic placement of some of the OTUs listed in Table 2.…”

“…L. pinastri and C. minus (Gourbière et al 2001;Gourbière and Debouzie 2003). Results from Prihatini et al 2015a also indicated that needle fungal communities may be highly variable amongst trees at a single site. A key part of the original experimental design involved conducting a needle-health survey in the 12 sites sometime during the following 3 years, when the Table 3 The major OTUs present in 12 young P. radiata plantations in Tasmania Entries in columns 2 to 13 indicate the number of pooled DNA samples in which the OTU was found at a particular site.…”

“…More recently, fungal communities were surveyed in a P. radiata family trial established in 1999 in Oonah, Tasmania. The trial was assessed at 8 years of age in 2007 using DNA extraction from needles, polymerase chain reaction (PCR) with fungal-specific primers and sequencing to detect the presence of fungal species (Prihatini et al 2015a). Trees with contrasting levels of SNC disease severity were found to have significantly different needle fungal communities.…”