Biology subjects

La Spada, F.

Publications and source records attributed to La Spada, F..

4 recordsLinked to original sources

bioRxiv2024

Biological Control of Green Mold in Simulated Post-harvest Chain of Citrus Fruit: Efficacy of Candida oleophila Strain O and Molecular Insight into Elicitation of Host Immune System

Managing post-harvest decays in citrus fruit without relying on conventional pesticides presents a significant challenge in modern Plant Pathology. This study aimed to evaluate the efficacy of the biological control agent Candida oleophila strain O in controlling green mold caused by Penicillium digitatum throughout various stages of the post-harvest supply chain. Using a series of in vivo experiments, different scenarios of P. digitatum infections in clementine tangerine, orange, and lemon fruit were examined, with treatments applied before, during or after infection. The study simulated typical conditions of the citrus supply chain, including picking, processing in packinghouses, and transportation, as well as cold storage and shelf-life phases. Results indicated that C. oleophila exhibited significant efficacy in reducing green mold symptoms, even at shelf-life temperatures, making it a practical alternative to conventional fungicides. Additionally, the study provided insights into the molecular mechanisms underlying the defensive response of citrus fruit to C. oleophila treatment, with up-regulation of defense-related genes observed across different fruit types. Overall, this study underscores the potential of C. oleophila as a sustainable and effective solution for managing post-harvest decays in citrus fruit within the complexities of the supply chain.

plant biology↗

bioRxiv2023

Recombinase Polymerase Amplification Assay for the Field Detection of Mal Secco Disease by Plenodomus tracheiphilus

In this study, we developed a new diagnostic assay based on the recombinase polymerase amplification (RPA) technology to detect Plenodomus tracheiphilus, the anamorphic fungus responsible for the destructive vascular disease of lemon named mal secco, in infected tissues of host plants. A 142 bp RPA-compatible barcode was sought within the 544 bp Internal Transcriber Spacer (ITS) fragment identified in a previous study and its P. tracheiphilus-specificity was confirmed by BLAST in the NCBI database. This was the premise to design an RPA probe (RPA_Ptrach_Probe). The specificity and inclusivity of the RPA assay were tested on gDNA isolated from tissues of C. limon, isolates of P. tracheiphilus of various origins and axenic cultures of non-target organisms, including fungal and oomycete pathogens typically associated to citrus trees, such as Alternaria spp., Colletotrichum spp., Phyllosticta spp., Penicillium spp., Phytophthora spp. With a detection threshold of 1.0 pg of gDNA the RPA assay proved to be as sensitive as the SYBR(R) Green I Real Time-PCR test included in the diagnostic protocol for P. tracheiphilus of the European and Mediterranean Plant Protection Organization. RPA assay was even more sensitive than Real Time-PCR in tests on DNA samples obtained through a rapid extraction method. In tests, on naturally infected lemon twigs, molecular approaches were comparable to each other and performed better than conventional isolation method. Overall, results of this study demonstrate the potential of RPA for rapid, easy to handle and cost effective in-field diagnosis of mal secco.

molecular biology↗

bioRxiv2023

Diversity of mycotoxins and other secondary metabolites re-covered from blood oranges infected by Colletotrichum, Alternaria, and Penicillium species.

This study identified secondary metabolites produced by Alternaria alternata, Colletotrichum gloeosporioides and Penicillium digitatum in fruits of two blood orange cultivars before harvest. Analysis was performed by UHPLC-Q-TOF-MS. Three types of fruits were selected, asymptomatic, symptomatic showing necrotic lesions caused by hail, and mummified. Extracts from peel and juice were analyzed separately. Penicillium digitatum was the prevalent species recovered from mummified and hail-injured fruits. Among 47 secondary metabolites identified, 16, 18 and 13 were of A. alternata, C. gloeosporioides and P. digitatum, respectively. Consistently with isolations, indicating the presence of these fungi also in asymptomatic fruits, the metabolic profiles of the peel of hail-injured and asymptomatic fruits did not differ substantially. Major differences were found in the profiles of juice from hail injured and mummified fruits, such as a significant higher presence of 5,4-dihydroxy-3,7,8-trimethoxy-6C-methylflavone and Atrovenetins, particularly in the juice of mummified fruits of Tarocco Lempso cultivar. Moreover, the mycotoxins Patulin and Rubratoxin B were detected exclusively in mummified fruits. Patulin was detected in both the juice and peel, with a higher relative abundance in the juice, while Rubratoxin B was detected only in the juice. These findings provide basic information for evaluating and preventing the risk of contamination by mycotoxins in the citrus fresh fruit supply chain and juice industry.

plant biology↗

bioRxiv2021

Depriving mice of sleep also deprives of food

Both sleep-wake behavior and circadian rhythms are tightly coupled to energy metabolism and food intake. Altered feeding times in mice are known to entrain clock-gene rhythms in brain and liver and sleep-deprived humans tend to eat more and gain weight. Previous observations in mice showing that sleep deprivation (SD) changes clock-gene expression might thus relate to altered food intake and not to the loss of sleep per se. Whether SD affects food intake in the mouse and how this might affect clock-gene expression is, however, unknown. We therefore quantified i) the cortical expression of the clock genes Per1, Per2, Dbp, and Cry1 in mice that had access to food or not during a 6h SD, and ii) food intake during baseline, SD, and recovery sleep. We found that food deprivation did not modify the SD-incurred clock-gene changes in the cortex. Moreover, we discovered that although food intake during SD did not differ from baseline, mice lost weight and increased food intake during subsequent recovery. We conclude that SD is associated with food deprivation and that the resulting energy deficit might contribute to the effects of SD that are commonly interpreted as a response to sleep loss.

physiology↗