Antagonistic Fungal Endophytes against Blue stain-associated Fungus from Benguet Pine (Pinus kesiya Royle ex Gordon)

Valdez, Shirley Jaene S.

In light of mycology and conservation of the Cordillera’s important tree species, the Benguet pine (Pinus kesiya Royle ex Gordon), investigation of its fungal communities is necessary. While study on pines stain disease was conducted in Mindanao, investigation of this disease was not yet done in Luzon. Furthermore, endophytic fungi (EF) were reported to confer benefits to their host plant like increased disease resistance. The study isolated and screened EF as antagonistic agents against Blue stain-associated fungus (BSAF). Morphological and molecular results showed seven (7) EF associated with B pine bark. These are Cladosporium sp. strain ALEF-C1 (designated as EF1), Cladosporium sp. IS547 (EF2), Eupenicillium javanicum (EF3), Hypocrea nigricans (EF4), Mucor sp. (EF5), Phaemoniella chlamydospora (EF6), and Trichoderma sp. 49 (EF7). The two Cladosporium spp. corresponded with previous study of Pinus densiflora and Pinus rigida needle endophytes in Daejeon, Korea while Mucor spp. were reported as root endophytes of Pinus thunbergii. The rest were not yet reported to be found in pines. The isolated BSAF in B pine from Luzon coincided with the report of Austral in 1992 in which Trichoderma koningii, with H. koningii as its anamorph, was isolated from pines in Musuan, Bukidnon. EF4 and BSAF were phylogenetically related which could mean that BSAF could be an endophyte. Hence, pathogenicity test of BSAF is recommended. Antagonistic potential of the four (4) isolated EF against the BSAF was also assessed through dual-culture method. All EF showed the ability to inhibit the growth of isolated BSAF with EF4 having the highest antagonistic activity (45%) followed by EF3 (30%); EF1 (23%) and EF2 (13%). The antagonism could be due to production of cell-wall degrading enzymes such as the chitinase and mycotoxins. Although the study contributed to the limited information about fungal communities of forest tree species in the country, investigation of active metabolites of the identified EF, exploration of EF from other parts aside from the bark and pathogenicity of the BSAF could also be done in future researches.