百香果茎基腐病病原菌鉴定及其生物学特性.

[Objective] To clarify the pathogenic fungus of passion fruit stem rot and its biological characteristics, and to provide theoretical basis for its scientific prevention and control. [Method] This paper used the conventional isolation method of phytopathogenic fungi to isolate the stem-base rot pathogen of passion fruit collected from Guangxi under different ecological conditions. The morphological characteristics were observed and the pathogenic traits were determined. The rDNA-ITS sequences were analyzed to identify the pathogenic fungus causing passion fruit stem rot. [Result] The same morphological strain 32-WUB3 was isolated from typical pass ion fruit stem rot symptomatic plants collected from various pass ion fruit planting bases in Guangxi. After morphological, molecular biological and pathogenicity tests, Lasiodiplodia theobromae was identified as the causal agent of passion fruit stem rot. The mycelial growth rate of the pathogen was high at 28 and 30°C. The colony diameters were 8. 27 and 8. 31 cm, respectively, which were extremely significantly higher than those at other temperatures (P < 0. 01, the same as below). The fastest mycelial growth was under full light conditions, with a colony diameter of 8. 49 cm. Its diameter was extremely significantly higher than that of colonies in total darkness, and significantly higher than that of colonies in half light and half darkness (P < 0. 05, the same as below). The optimum pH for mycelial growth was 3. 00 - 8. 00. In this pH range, the mycelium grew faster and the colony diameter reached 8. 10 - 8. 44 cm. The difference between treatments was not significant( P > 0. 05), but there was a significant difference in colony diameter from pH 9. 00 to 11. 00 for each treatment. Mycelium grew the fastest in PDA medium. Its colony diameter reached 9. 00 cm, which was extremely significantly higher than the colony diameter of other media Mycelium grew the fastest when the car bon source was glucose. The colony diameter reached 7. 78 cm, which was significantly higher than the colony diameter of other carbon sources. The mycelium grew the fastest when the nitrogen source was yeast powder. The colony diameter was 7. 13 cm. The nitrogen sources as followed were peptone, DL-alanine, L-arginine and glycine. The differences among the treatments were not significant, but all were significantly higher than the colony diameter with beef paste, urea, ammonium dihydrogen phosphate, ammonium chloride, L-lysine and CK as the nitrogen source. The mycelial lethal conditions of this pathogenic mycelium were 52°C and 10 min of treatment [Conclusion] L. theobromae is the causal agent of stem rot of passion fruit The suitable temperature for mycelial growth of this pathogen was 28 - 30°C, pH was 3. 00 - 8. 00, lighting was full light, and the medium was PDA The carbon source was glucose, the nitrogen source was yeast powder, and the mycelial lethal condition was treatment at 52°C for 10 min. [ABSTRACT FROM AUTHOR]