4HNR(1,3,6,8-tetra-HN reductase)gene of melanin biosynthesis in Setosphaeria turcica had been cloned successfully by RT-PCR in this study.Both sequences of DNA and cDNA of 4HNR were 807 bp and there was no intron in the sequences.This gene only had single copy in genome through Southern blotting analysis.A 2 285 bp for the flanking sequence of 5’ had been obtained and it had promoter structure through the software analysis.
Factors of influence on conidium germination and appressorium formation of Setosphaeria turcica,such as light condition,conidial concentration,nutrient resources and pH value of conidial suspension were studied.There was no significant difference among light treatments.The optimal pH for conidium germination and appressorium formation was 5.0 to 7.0.The exogenous nutrient sources were not the indispensable factors for conidium germination,but 5% sugar solution were more favorable for appressorium formation than the others.Low conidial concentration in suspension(conidia ≤104/mL)was propitious to conidium germination and appressorium formation,which were inhibited significantly in higher concentration.It was suggested that the phenomenon was due to the self-inhibitor,a kind of lipophilic substance,existing in the site of conidium germination.
