Symptoms of sclerotinia stem rot of Ligusticum chuanxiong were observed and the causal agent of the disease was identified.The results showed that the symptoms of this disease began with the formation of dark brown hygrophanous splotch on the basal leaves,followed by the appearance of dark brown circular spot on the basal stem.Finally,the whole plant stoped growing and died.White mycelium and/or sclerotia were formed under moisturized conditions.On PDA medium,the pathogen of this disease formed brown sclerotia with various shapes and 2-5 mm in diameter.The diameter of apothecia was 0.3-0.8 cm and the length of stipes was 2-8 cm.Asci were columniform in shape and(100-135)×9 μm in size,each containing 8 ascospores sized by(6-12) μm×(3-7) μm.No asexual spore formation was observed.Based on the morphological characteristics and the sequence of ribosomal DNA-ITS,the pathogen was identified as Sclerotinia sclerotiorum(Lib.) de Bary.
[Objective] The study aimed to establish a protoplast transformation system in Alternaria tenuissima. [Method] The protoplast of A.tenuissima was firstly prepared by enzymolysis method; then the yielded protoplast was transformed by G418 resistant DNA plasmid using PEG/CaCl2 method. [Result] The growth phenotype and PCR detection showed that resistance gene had integrated into A.tenuissima genome. The transformation efficiency of this method reached per μg DNA 3-4 transformants. After subculture thrice under nonselective condition, G418 resistance could still inherit stably. [Conclusion] The transformation system of A.tenuissima was successfully established, which laid basis for studying of the gene function of Alternaria tenuissima.
