Search Results (3)

The APETALA2/ethylene response factor (AP2/ERF) is a class of plant-specific transcription factors, among which the dehydration-responsive element-binding protein (DREB) subfamily has been widely reported to enhance plant resistance to abiotic stresses. A high-temperature-related gene, Apium graveolens DREBA6b (AgDREBA6b; accession number: OR727346), was previously cloned from a heat-tolerant celery variety. In this study, we transformed this gene into Arabidopsis thaliana using an Agrobacterium rhizogenes-mediated method to explore its function. The results showed that overexpressing AgDREBA6b in Arabidopsis thaliana significantly improved plant growth under high-temperature stress (38 °C) compared to the dreb mutant and wild-type (WT) plants. The anatomical structure of the leaves revealed that the number and degree of stomatal openings in the overexpressed plants were significantly higher than those in the WT and dreb plants, suggesting that AgDREBA6b enhances stomatal opening. Additionally, the chlorophyll content, chlorophyll fluorescence properties, proline (Pro), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) activities were higher in the transgenic plants, indicating better stress tolerance. qPCR analysis showed that four heat tolerance-related genes (AtHSP98.7, AtHSP70-1, AtAPX1, and AtGOLS1) were upregulated in the transgenic plants, with higher expression levels than in WT and mutant plants. This study provides valuable genetic resources for understanding the molecular mechanisms of celery’s heat tolerance and offers insights for breeding heat-tolerant celery varieties. Full article

Celery (Apium graveolens L.) is a vegetable belonging to the Apiaceae family that is widely used for its distinct flavor and contains a variety of bioactive metabolites with healthy properties. Some celery ecotypes cultivated in specific territories of Italy have recently attracted the attention of consumers and scientists because of their peculiar sensorial and nutritional properties. In this work, the volatile profiles of white celery “Sedano Bianco di Sperlonga” Protected Geographical Indication (PGI) ecotype, black celery “Sedano Nero di Torricella Peligna” and wild-type celery were investigated using head-space solid-phase microextraction combined with gas-chromatography/mass spectrometry (HS-SPME/GC-MS) and compared to that of the common ribbed celery. Exploratory multivariate statistical analyses were conducted using principal component analysis (PCA) on HS-SPME/GC-MS patterns, separately collected from celery leaves and petioles, to assess similarity/dissimilarity in the flavor composition of the investigated varieties. PCA revealed a clear differentiation of wild-type celery from the cultivated varieties. Among the cultivated varieties, black celery “Sedano Nero di Torricella Peligna” exhibited a significantly different composition in volatile profile in both leaves and petioles compared to the white celery and the prevalent commercial variety. The chemical components of aroma, potentially useful for the classification of celery according to the variety/origin, were identified. Full article

Pectobacterium carotovorum is a gram-negative bacterium that, together with other soft rot Enterobacteriaceae causes soft rot disease in vegetables, fruits, and ornamental plants through the action of exoproteins including plant cell wall-degrading enzymes (PCWDEs). Although pathogenicity in these bacteria is complex, virulence levels are proportional to the levels of plant cell wall-degrading exoenzymes (PCWDEs) secreted. Two low enzyme-producing transposon Tn5 mutants were isolated, and compared to their parent KD100, the mutants were less virulent on celery petioles and carrot disks. The inactivated gene responsible for the reduced virulence phenotype in both mutants was identified as wcaG. The gene, wcaG (previously denoted fcl) encodes NAD-dependent epimerase/dehydratase, a homologue of GDP-fucose synthetase of Escherichia coli. In Escherichia coli, GDP-fucose synthetase is involved in the biosynthesis of the exopolysaccharide, colanic acid (CA). The wcaG mutants of P. carotovorum formed an enhanced level of biofilm in comparison to their parent. In the hydrophobicity test the mutants showed more hydrophobicity than the parent in hexane and hexadecane as solvents. Complementation of the mutants with extrachromosomal copies of the wild type gene restored these functions to parental levels. These data indicate that NAD-dependent epimerase/dehydratase plays a vital rule in cell surface properties, exoenzyme production, and virulence in P. carotovorum. Full article