Macrophomina vaccinii sp. nov. causing blueberry stem blight in China

Blueberries (Vaccinium spp.) have been widely cultivated in China because of their nutritional benefits and economic value. Blueberry stem blight has become one of the most severe diseases influencing blueberry productivity and quality in China. In this study, eight fungal isolates were obtained from twenty stem blight lesions of blueberry collected in Nanping, Fujian province, China. Asexual stage was observed after inducing sporulation, the morphology of which agrees with Macrophomina in the black, smooth, hard sclerotia and ellipsoid to obovoid, smooth hyaline conidia with apical sheath. Furthermore, DNA sequences of concatenated ITS, tef1-α, TUB, and ACT loci indicated that these isolates belong to a novel fungal species. The distinguishing morphological characteristics, such as the wider conidia and larger conidiomata pycnidial, also support its new status. Thus a novel fungus, Macrophominavaccinii, was described in this study. Pathogenicity tests indicated that M.vaccinii could cause stem blight of blueberry.