Analysis the sclerosphere microrganism community of Sclerotinia sclerotiorum and evaluation of its effect on infection of sclerotia by Coniothyrium minitans

• 1、The Key Laboratory of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, 430070, China

Abstract：Coniothyrium minitans is a mycoparasite of the plant pathogenic fungus Sclerotinia sclerotiorum. It can parasitize sclerotia of S. sclerotiorum, reducing apothecial production and disease incidence. In natural soils, effect of sclerosphere microbes on infection of S. sclerotiorum sclerotia by C. minitans is poorly understood. This study focused on the ecology of the sclerosphere microorganism community of S. sclerotiorum, used molecular techniques and isolation techniques. Results showed that the amount of bacteria and fungi in sclerosphere are significantly higher than those in sclerotia-free soils. Two hundred and fifty-three bacteria and one hundred and eighty fungi were isolated from sclerosphere soil. Base on bacterial 16S rDNA and fungal internal transcribed spacer of ribosomal DNA sequences, we identified Pseudomons and Bacillus as the dominant genera in sclerosphere. Penicillium was dominant genus in sclerosphere. Server bacteria showed strong in vitro antagonism to the mycelial growth of S. sclerotiorum and C. minitans. Seven bacteria strains could strongly suppress infection of sclerotia by C. minitans in vitro. This result suggests that sclerosphere bacteria may play an important role in suppression of the infection of sclerotia by C. minitans in field.

Keywords： Sclerotinia sclerotiorum Coniothyrium minitans sclerosphere microbial diversity biological control