New reports of pathogen spectrum associated with bulb rot and their interactions during the development of rot in tulip.

Bulb rot, a highly damaging disease of tulip plants, has hindered their profitable cultivation worldwide. This rot occurs in both field and storage conditions posing significant challenges. While this disease has been attributed to a range of pathogens, previous investigations have solely examined it within the framework of a single-pathogen disease model. Our study took a different approach and identified four pathogens associated with the disease: Fusarium solani, Penicillium chrysogenum, Botrytis tulipae, and Aspergillus niger. The primary objective of our research was to examine the impact of co-infections on the overall virulence dynamics of these pathogens. Through co-inoculation experiments on potato dextrose agar, we delineated three primary interaction patterns: antibiosis, deadlock, and merging. In vitro trials involving individual pathogen inoculations on tulip bulbs revealed that B. tulipae,was the most virulent and induced complete bulb decay. Nonetheless, when these pathogens were simultaneously introduced in various combinations, outcomes ranged from partial bulb decay to elongated rotting periods. This indicated a notable degree of antagonistic behaviour among the pathogens. While synergistic interactions were evident in a few combinations, antagonism overwhelmingly prevailed. The complex interplay of these pathogens during co-infection led to a noticeable change in the overall severity of the disease. This underscores the significance of pathogen-pathogen interactions in the realm of plant pathology, opening new insights for understanding and managing tulip bulb rot.

One year later: The effect of changing azole-treated bulbs for organic tulips bulbs in hospital environment on the azole-resistant Aspergillus fumigatus rate.

Azole-treated plant bulbs have already been evoked as a potential explanation of the worldwide spread of azole-resistant Aspergillus fumigatus (ARAf). We previously pointed out the presence of a high rate of ARAf (71% of A. fumigatus detected on azole-supplemented media) in flower beds containing azole-treated bulbs at the hospital's surroundings. We show here that planting organic bulbs can be a solution to reduce ARAf burden (from 71% rate to below 3%). The results suggest that replacing treated bulbs with organic bulbs may be sufficient to regain a population that is predominantly susceptible in just 1 year. LAY SUMMARY: Antifungal resistance is increasingly observed in fungal pathogens. This study argues that planting organic bulbs in hospitals' outdoor surroundings could be a good alternative to continue to beautify green spaces, without the risk of dissipating antifungal-resistant fungal pathogens.

Asymmetric total synthesis of 6-Tuliposide B and its biological activities against tulip pathogenic fungi.

The structure-activity relationship was investigated to evaluate the antifungal activities of tuliposides and tulipalins against tulip pathogenic fungi. 6-Tuliposide B was effectively synthesized via the asymmetric Baylis-Hillman reaction. Tuliposides and tulipalins showed antifungal activities against most of the strains tested at high concentrations (2.5 mM), while Botrytis tulipae was resistant to tuliposides. Tulipalin formation was involved in the antifungal activity, tulipalin A showed higher inhibitory activity than 6-tuliposide B and tulipalin B. Both the tuliposides and tulipalins showed pigment-inducing activity against Gibberella zeae and inhibitory activity against Fusarium oxysporum f. sp tulipae. These activities were induced at a much lower concentration (0.05 mM) than the antifungal MIC values.

Host-derived media used as a predictor for low abundant, in planta metabolite production from necrotrophic fungi.

AIMS: Penicillium ser. Corymbifera strains were assayed on a variety of media and from infected Allium cepa tissues to evaluate the stimulation and in planta prediction of low abundance metabolites. METHODS AND RESULTS: Stimulated production of corymbiferones and the corymbiferan lactones were observed for Penicillium albocoremium, Penicillium allii, Penicillium hirsutum, Penicillium hordei and Penicillium venetum strains cultured on tissue media. Target metabolites were sporadically detected from strains cultured on common laboratory media (CYA, MEA and YES). Up to a 376 times increase in corymbiferone and corymbiferan lactone production was observed when culture extracts from CYA and A. cepa agar were compared by high pressure liquid chromatography with ultraviolet and mass spectrometry (LC-UV-MS). The novel metabolite corymbiferone B was purified and structure elucidated from a P. allii/A. cepa tissue medium extract. In planta expression of low abundance, target metabolites were confirmed from infected A. cepa tissue extracts by LC-UV-MS. CONCLUSIONS: Secondary metabolite production was directly dependent and influenced by media conditions, resulting in the stimulated production of low abundance metabolites on host-derived media. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of macerated host tissue media can be applied in vitro to predict in planta expression of low abundance metabolites and aid in metabolite origin annotation during in planta metabolomic investigations at the host/pathogen interface.

Pythium oligandrum in the control of Fusarium rot on some bulbous plants.

Pythium oligandrum was applied as tulip bulbs or gladiolus corms soak prior or after inoculation with formae speciales Fusarium oxysporum. The mycoparasite used before inoculation with pathogen suppressed the development of Fusarium rot. This effect was not observed, however, when P. oligandrum was used 24 hr after bulb inoculation. Soaking of forced tulip bulbs in oospore suspension of P. oligandrum may reduce Fusarium rot spread and increase number of flowers, but at conc. 2.5 x 10(3)-10(4)/cm3 caused inhibition of tulip root growth.