Project description:The use of Biological Control Agents (BCAs) to cope diseases has received considerable attention owing to its high efficiency and environmental safety. The aim of our study was to investigate the potential role of the Pseudomonas mediterranea pre-treatments in the response of lemon [Citrus limon (L.) Burm. f.] against mal secco, this being a devastating citrus disease caused by the fungus Plenodomus tracheiphilus. RNAseq analysis revealed that the fungus induced a marked reprogramming of the transcriptome, but P. Mediterranea pre-treatments strongly reduced lemon leaf transcriptome modifications and limited the amount of the fungus DNA inside the plant tissue. Furthermore, P. mediterranea prevented the down regulation of the genes involved in the effector triggered immunity (ETI) and the deregulation of genes involved in the main phytohormone’s biosynthesis and perception. As far as we know, this work represents the first report on the analysis of P. tracheiphilus-lemon plant-BCA interaction at molecular level.
Project description:Mal secco is one of the most severe diseases of citrus, caused by the necrotrophic fungus Plenodomus tracheiphilus that is widespread in different Mediterranean countries. With the main aim of identifying candidate genes involved in the response of citrus plants to “Mal secco”, we performed a de novo transcriptome analysis of rough lemon seedlings subjected to artificial inoculation of P. tracheiphilus in comparison with plants inoculated with water. The analysis of Differential Expressed Genes (DEGs) highlighted a sharp response triggered by the pathogen as a total of 4,986 significant DEGs (2,865 genes up-regulated and 2,121 down-regulated) have been revealed. The analysis of the most significantly enriched KEGG pathways indicated that a crucial role in the plant response to the fungus is played by genes involved in “Plant hormone signal transduction”, “Phenylpropanoid biosynthesis” and “Carbon metabolism”. The main findings of this work are that under fungus challenge, the rough lemon genes involved both in the light harvesting and the photosynthetic electron flow were significantly down-regulated, thus probably inducing a shortage of energy for cellular functions. Moreover, the systemic acquired resistance (SAR) was activated through the induced salicylic acid cascade. Interestingly, RPM1 interacting protein 4, an essential positive regulator of plant defense, and BIR2, which is a negative regulator of basal level of immunity, have been identified thus representing useful targets for molecular breeding.
Project description:Mal secco is one of the most severe diseases of citrus, caused by the necrotrophic fungus Plenodomus tracheiphilus. With the main aim of identifying candidate genes involved in the response of citrus plants to "Mal secco", we performed a de novo transcriptome analysis of rough lemon seedlings subjected to inoculation of P. tracheiphilus. The analysis of differential expressed genes (DEGs) highlighted a sharp response triggered by the pathogen as a total of 4986 significant DEGs (2865 genes up-regulated and 2121 down-regulated) have been revealed. The analysis of the most significantly enriched KEGG pathways indicated that a crucial role is played by genes involved in "Plant hormone signal transduction", "Phenylpropanoid biosynthesis", and "Carbon metabolism". The main findings of this work are that under fungus challenge, the rough lemon genes involved both in the light harvesting and the photosynthetic electron flow were significantly down-regulated, thus probably inducing a shortage of energy for cellular functions. Moreover, the systemic acquired resistance (SAR) was activated through the induced salicylic acid cascade. Interestingly, RPM1 interacting protein 4, an essential positive regulator of plant defense, and BIR2, which is a negative regulator of basal level of immunity, have been identified thus representing useful targets for molecular breeding.
