Fungi associated with disease symptoms on Pinus mugo needles in the Polish Tatra Mountains

Abstract

Dwarf mountain pine, Pinus mugo, is an important component of the subalpine and alpine zone in Europe. For several years, in one of the natural areas of the occurrence of this species in the Polish Tatras, an intensified decline of the assimilation apparatus has been observed. The studies conducted in 2016–2020 were aimed at determining the types of disease symptoms occurring on P. mugo needles and at identifying the species composition of fungi within symptomless and diseased needles. We isolated 57 taxa from 6 types of disease symptoms and from needles without disease symptoms, identified on the basis of morphological features and molecular analyses. Absolute parasites were represented by only one species of Coleosporium senecionis, which was identified by the aecium stage. The genus Lophodermium was represented by three species: L. conigenum, L. corconticum and L. pini-mugonis. So far, L. corconticum was known only from the Karkonosze Mountains in Poland, and L. pini-mugonis from the German Alps. In addition, the more frequently isolated species included: Sydowia polyspora, Hendersonia sp., Nemania serpens, Leptomelanconium allescheri, Cladosporium spp., Biscogniauxia nummularia and Alternaria spp. Some taxa were associated with only one type of disease symptom, while some species of fungi were found to be associated with different symptoms. Twelve species of fungi were isolated from living symptomless needles, some of which were subsequently found in association with nectrotic areas on needles, e.g., Lophodermium corconticum, L. conigenum and Leptomelanconium allescheri. L. pinastri has not been found in the present studies. In the discussion, an attempt was made to assess the role of some of the identified species of fungi in causing the disease process of P. mugo needles.

Involvement of Lophodermella sulcigena in Endemic Disease of Pinus mugo Needles in the Polish Tatra Mountains

“…Three species, Lophodermium corconticum, Lo. pini-mugonis and Leptomelanconium allescheri, have been detected for P. mugo in this region for the first time [28,29]. The only fungal species that was found in each symptomatic needle group and also in living symptomless needles was Lo.…”

“…Field observations were carried out on seven plots (1.5-5.5 a) located in dense clumps of P. mugo at an altitude of 1556 to 1746 m a.s.l., where an average of 44%-65% needles with discoloration and necrosis were present. The location of these plots and the severity of the needle disease were presented by Bartnik et al [28]. The samples were collected in autumn 2015 and at least four times in the period from May to November in 2016, 2017, and 2020, and were also used for conducting research on other diseases of P. mugo needles [28].…”

“…The location of these plots and the severity of the needle disease were presented by Bartnik et al [28]. The samples were collected in autumn 2015 and at least four times in the period from May to November in 2016, 2017, and 2020, and were also used for conducting research on other diseases of P. mugo needles [28]. For the purposes of the current study, a detailed description and documentation of selected types of symptoms on this year's needles, and their changes on two-year and three-year-old needles, was performed.…”

“…For several years in Polish Tatra, there has been a high intensity of P. mugo needle diseases in some regions [28]. During the preliminary analysis, several different types of disease symptoms on the needles were distinguished, and an attempt was made to determine which fungi can be associated with these symptoms.…”

“…During the preliminary analysis, several different types of disease symptoms on the needles were distinguished, and an attempt was made to determine which fungi can be associated with these symptoms. In total, more than fifty fungal taxa were found in symptomatic and symptomless needles [28]. Three species, Lophodermium corconticum, Lo.…”