Biology subjects

Ducasse, D. A.

Publications and source records attributed to Ducasse, D. A..

3 recordsLinked to original sources

bioRxiv2022

SOYBEAN RESPONSE TO INITIAL STAGE OF Fusarium virguliforme INFECTION

Fusarium virguliforme causes the Sudden Death Syndrome, an important disease in soybean crops. In this work, we investigated the defensive response mechanisms in soybean root, at cell wall level, during F. virguliforme infection using an in vitro culture system. We measured total root lignin content by the acetyl bromide method and estimated the in-situ lignin and suberin deposition by confocal microscopy on local and systemic root tissues, i.e. adjacent and distant to the pathogen entry site respectively. Moreover, the expression dynamics of phenylalanine ammonia lyase (PAL), shikimate/quinate hydroxycinnamoyltransferase (HCT) and cinnamyl alcohol dehydrogenase (CAD) was evaluated by real-time quantitative PCR. The results showed that, although the most significant increment of lignin deposition was observed in the epidermal cells of local tissues, F. virguliforme also induced lignin deposition changes in a sistemic fashion. In fact, inoculated plants presented a higher deposition of lignin in hypodermis and cortex than the control ones, independently of the distance from the inoculum source, while suberin deposition was higher in local zones. Moreover, the gene expression analysis showed an up-regulation of PAL, HCT and CAD genes after the inoculation with the pathogen, which correlates with the cell wall modifications observed in the local tissues. The results presented here suggest that the increase in lignin and suberin deposition during soybean root/F. virguliforme interaction is probably a strategy not only to stop the pathogen entrance, but to provide the plant more time to prepare its defences as well.

plant biology↗

bioRxiv2019

Development of an innovative in vitro method for mass production of Verticillium dahliae microsclerotia

The soil-borne fungal plant pathogen Verticillium dahliae can infect more than 300 plant species including important economic crops, causing great economic loses. V. dahliae can persist and survive more than 14 years in the soil by resistance structures, known as microsclerotia, which constitute the primary inoculum in the field. In vitro mass production of microsclerotia is essential for performing many pathological assays. Nevertheless to harvest the microsclerotia is not an easy task and several protocols have been described although none of them is completely satisfying for different reasons. here we present a new protocol that is reproducible, robust, simple and fast allows to overcome the difficulties for obtaining massive amounts of microsclerotia. In summary, we developed a new culture medium that we called Pluronic Potato Medium (PPM) because it is essentially potato dextrose media with the hydrogel, Pluronic F127 as a solidifying agent. The microsclerotia collected in form PPM were infectious in tomato plants were they were able to reproduce the disease and we recovered and quantitated V. dahliae in infected plants.

microbiology↗

bioRxiv2018

Transcriptome analysis of mycorrhizal and non-mycorrhizal soybean plantlets upon infection with Fusarium virguliforme, one causal agent of sudden death syndrome

Soilborne pathogens represent a threat to agriculture causing important yield losses. The \"Sudden Death Syndrome\" (SDS), a severe disease in soybean is caused by a complex of Fusarium species. This pathosystem has been widely investigated and several strategies were proposed to manage SDS. Although a decrease in symptoms and in the level of root tissue infection particularly by F. virguliforme was observed in presence of arbuscular mycorrhizal fungi (AMF), biological control based on AMF has received less attention. Here we report the results, under strict in vitro culture experimental conditions, a transcriptional analysis in mycorrhizal versus non-mycorrhizal soybean plantlets upon infection by F. virguliforme. An important transcriptional reprogramming was detected following infection by the pathogen. Results revealed 1768 and 967 differentially expressed genes in the AMF-colonized (+AMF+Fv) and non-colonized (-AMF+Fv) plants, respectively. Major transcriptional changes, corresponded to defence response related genes belonging to secondary metabolism, stress and signalling categories. The +AMF+Fv treatment showed the largest number of upregulated genes related to defence, as those encoding for disease resistance proteins, WRKY transcription factors, auxins, receptors kinases, and proteases. Only few genes had primed expression in +AMF+Fv treatment, as those coding for a thaumatin-like protein (TLP) and a pleiotropic drug resistance (PDR) protein. Moreover, +AMF+Fv showed a significant number of downregulated genes related to cell wall modification and peroxidases than - AMF+Fv treatment. This detailed insight increases our knowledge on the transcriptional changes and the potential metabolic pathways involved in the enhanced resistance/tolerance of mycorrhizal plants upon infection with F. virguliforme.

plant biology↗