RESUMO
BACKGROUND: Mexico is considered the diversification center for chili species, but these crops are susceptible to infection by pathogens such as Colletotrichum spp., which causes anthracnose disease and postharvest decay in general. Studies have been carried out with isolated strains of Colletotrichum in Capsicum plants; however, under growing conditions, microorganisms generally interact with others, resulting in an increase or decrease of their ability to infect the roots of C. chinense seedlings and thus, cause disease. RESULTS: Morphological changes were evident 24 h after inoculation (hai) with the microbial consortium, which consisted primarily of C. ignotum. High levels of diacylglycerol pyrophosphate (DGPP) and phosphatidic acid (PA) were found around 6 hai. These metabolic changes could be correlated with high transcription levels of diacylglycerol-kinase (CchDGK1 and CchDG31) at 3, 6 and 12 hai and also to pathogen gene markers, such as CchPR1 and CchPR5. CONCLUSIONS: Our data constitute the first evidence for the phospholipids signalling events, specifically DGPP and PA participation in the phospholipase C/DGK (PI-PLC/DGK) pathway, in the response of Capsicum to the consortium, offering new insights on chilis' defense responses to damping-off diseases.
Assuntos
Capsicum/imunologia , Colletotrichum/fisiologia , Consórcios Microbianos/fisiologia , Fosfolipídeos/metabolismo , Doenças das Plantas/imunologia , Imunidade Vegetal , Transdução de Sinais , Capsicum/genética , Capsicum/microbiologia , Colletotrichum/isolamento & purificação , Diacilglicerol Quinase , Difosfatos/metabolismo , Glicerol/análogos & derivados , Glicerol/metabolismo , Interações Hospedeiro-Patógeno , Ácidos Fosfatídicos/metabolismo , Filogenia , Doenças das Plantas/microbiologia , Raízes de Plantas/genética , Raízes de Plantas/imunologia , Raízes de Plantas/microbiologia , Plântula/genética , Plântula/imunologia , Plântula/microbiologia , Fosfolipases Tipo C/metabolismoRESUMO
Human and yeast mitochondrial DNA polymerases (DNAPs), POLG and Mip1, are related by evolution to bacteriophage DNAPs. However, mitochondrial DNAPs contain unique amino and carboxyl-terminal extensions that physically interact. Here we describe that N-terminal deletions in Mip1 polymerases abolish polymerization and decrease exonucleolytic degradation, whereas moderate C-terminal deletions reduce polymerization. Similarly, to the N-terminal deletions, an extended C-terminal deletion of 298 amino acids is deficient in nucleotide addition and exonucleolytic degradation of double and single-stranded DNA. The latter observation suggests that the physical interaction between the amino and carboxyl-terminal regions of Mip1 may be related to the spread of pathogenic POLG mutant along its primary sequence.