Isolation and identification of symbiotic fungi in roots of Picea crassifolia on Helan Mountain in Ningxia, China

Abstract:

[Background] Picea crassifolia, an endemic plant with great ecological value in China, is an important tree species for forest regeneration and afforestation in desert mountain areas in Northwest China. The diverse symbiotic fungi in the roots of P. crassifolia contribute to its growth, development, and stress resistance. [Objective] The culturable symbiotic fungi were isolated from the roots of P. crassifolia on Helan Mountain and identified to reveal the fungal community composition. The results provide basic data for seedling breeding, afforestation, and ecosystem restoration of P. crassifolia. [Methods] The culturable symbiotic fungi in the roots of P. crassifolia were isolated directly from root tips and identified based on the morphological characteristics of colony and the rDNA ITS sequence. [Results] A total of 65 fungal strains were isolated from the roots of P. crassifolia, belonging to 18 species, 16 genera, 13 families, 8 orders, 4 classes of 1 phylum (Ascomycota). Phialocephala was the genus with the highest isolation frequency, with the isolates accounting for 31% of the total isolates. Phialocephala lagerbergi was the species with the highest isolation frequency (22%), followed by Cadophora interclivum (18%), Pleotrichocladium opacum (17%), Phialocephala fortinii (9%) and Alfoldi sp. (9%). The species and number of the symbiotic fungi varied at different development stages of P. crassifolia. The fungal isolation frequency in the roots of saplings, seedlings, and adult trees was 52%, 28%, and 20%, respectively. [Conclusion] The symbiotic fungi in the roots of P. crassifolia on Helan Mountain in Ningxia were diverse, the species and number of which varied at different development stages of the tree. All the isolated fungi in this study were obtained from P. crassifolia for the first time. The results are an important supplement to previous related studies, laying a foundation for further investigating the resources of culturable symbiotic fungi in the roots of P. crassifolia and exploring the role of symbiotic fungi in the process of P. crassifolia adapting to the alpine and arid environment.