Studies on a pathogenicity assay for screening cotton germplasms for resistance to Fusarium oxysporum f. sp. vasinfectum in the glasshouse

Abstract

Summary. Fusarium wilt, caused by Fusarium oxysporum f. sp. vasinfectum, is a new and important disease of cotton in Australia. Some factors affecting either the infection process or the subsequent development of symptoms under glasshouse conditions were examined in this study. The pathogenicity of inocula was significantly affected by the media in which they were produced. The most severe symptoms developed in the plants inoculated with the inoculum produced in Komada-Ezuka liquid medium, in which glucose and L-asparagine were used as the carbon and nitrogen source, respectively. Symptoms were significantly more severe in plants inoculated with the inocula suspended in culture filtrates than in those inoculated with the inocula suspended in distilled water, indicating that fungal metabolites played an important role in the infection process. The disease was enhanced by high conidial concentration (>1.0 x 106 conidia/mL), slightly acidic inoculum (pH 4.0–5.5) and longer inoculation period (5–25 min). One-week-old seedlings were most susceptible, regardless of cultivar, and the resistance of plants increased with their age. The development of symptoms was enhanced at a moderate temperature range (18–23°C), but suppressed at a higher temperature range (28–33°C). Based on these results, an optimised procedure of pathogenicity assay is described.

United States Department of Agriculture—Agricultural Research Service studies on polyketide toxins of Fusarium oxysporum f sp vasinfectum: potential targets for disease control

“…Fusarium wilt first appeared in Australia in 1993,21 and has spread rapidly in that country 22, 23. The causal pathogen attacks G hirsutum and, tentatively, has been identified as race 1.…”

Development of a rapid, accurate glasshouse bioassay for assessing fusarium wilt disease responses in cultivated Gossypium species

“…The protocol for a rapid and reliable high‐throughput Fov bioassay, based on the parameters optimized in this study and those of Wang et al. (1999), was as follows.…”

“…Plants were grown in a quarantine containment glasshouse and watered twice daily for 6 weeks, with 12 h at 28–30°C and 12 h at 15–18°C, as recommended by Wang et al. (1999).…”

“…, 1994). However, depending on the inoculum concentration, the length of time the plant is in contact with the inoculum and the aggressiveness of the Fov isolates used, escapes from infection are likely to occur (Wang et al. , 1999).…”

A Bioinformatics Framework for plant pathologists to deliver global food security outcomes

“…As a final example, the pathogen and environmental conditions may be appropriate for an incursion, but the opportunity for disease to be realised only occurs when a producer decides to use a variety of a crop that is susceptible to a disease lying dormant in the soil (e.g. Wang et al 1999). In all of these examples, data/information (e.g.…”