The Arabidopsis chromatin regulator MOM1 is a negative component of the defense priming induced by AZA, BABA and PIP

In plants, the establishment of broad and long-lasting immunity is based on programs that control systemic resistance and immunological memory or “priming”. Despite not showing activated defenses, a primed plant induces a more efficient response to recurrent infections. Priming might involve chromatin modifications that allow a faster/stronger activation of defense genes. The Arabidopsis chromatin regulator “Morpheus Molecule 1” (MOM1) has been recently suggested as a priming factor affecting the expression of immune receptor genes. Here, we show that mom1 mutants exacerbate the root growth inhibition response triggered by the key defense priming inducers azelaic acid (AZA), β-aminobutyric acid (BABA) and pipecolic acid (PIP). Conversely, mom1 mutants complemented with a minimal version of MOM1 (miniMOM1 plants) are insensitive. Moreover, miniMOM1 is unable to induce systemic resistance against Pseudomonas sp. in response to these inducers. Importantly, AZA, BABA and PIP treatments reduce the MOM1 expression, but not miniMOM1 transcript levels, in systemic tissues. Consistently, several MOM1-regulated immune receptor genes are upregulated during the activation of systemic resistance in WT plants, while this effect is not observed in miniMOM1. Taken together, our results position MOM1 as a chromatin factor that negatively regulates the defense priming induced by AZA, BABA and PIP.Instituto de Fisiología y Recursos Genéticos VegetalesFil: Miranda de la Torre, Julián O. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; ArgentinaFil: Miranda de la Torre, Julián O. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC). Departamento de Química Biológica-Ranwel Caputto; ArgentinaFil: Peppino Margutti, Micaela Y. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; ArgentinaFil: Peppino Margutti, Micaela Y. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC). Departamento de Química Biológica-Ranwel Caputto; ArgentinaFil: Lescano Lopez, Carlos Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Estudios Agropecuarios (UDEA) ; ArgentinaFil: Lescano Lopez, Carlos Ignacio. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Lescano Lopez, Carlos Ignacio. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; ArgentinaFil: Lescano Lopez, Carlos Ignacio.Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC). Departamento de Química Biológica-Ranwel Caputto; ArgentinaFil: Cambiagno, Damian Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Estudios Agropecuarios (UDEA) ; ArgentinaFil: Cambiagno, Damian Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales; ArgentinaFil: Cambiagno, Damian Alejandro.Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; ArgentinaFil: Alvarez, María E. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC). Departamento de Química Biológica-Ranwel Caputto; ArgentinaFil: Cecchini, Nicolás M. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC). Departamento de Química Biológica-Ranwel Caputto; Argentin

Protocol for analyzing the movement and uptake of isotopically labeled signaling molecule azelaic acid in Arabidopsis

Summary: Understanding the generation, movement, uptake, and perception of mobile defense signals is key for unraveling the systemic resistance programs in flowering plants against pathogens. Here, we present a protocol for analyzing the movement and uptake of isotopically labeled signaling molecule azelaic acid (AZA) in Arabidopsis thaliana. We describe steps to assess 14C-AZA uptake into leaf discs and its movement from local to systemic tissues. We also detail the assay for uptake and movement of 2H-AZA from roots to the shoot.For complete details on the use and execution of this protocol, please refer to Cecchini et al.1,2 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics

Fish And Agnor Mapping Of The 45s And 5s Rrna Genes In Wild And Cultivated Species Of Capsicum (solananceae).

Chromosome number and position of rDNA were studied in 12 wild and cultivated species of the genus Capsicum with chromosome numbers x = 12 and x = 13 (22 samples). For the first time in these species, the 5S and 45S rRNA loci were localized and physically mapped using two-color fluorescence in situ hybridization and AgNOR banding. We focused on the comparison of the results obtained with both methods with the aim of accurately revealing the real functional rRNA genes. The analyzes were based on a previous work that reported that the 18S-5.8S-25S loci mostly coincide with GC-rich heterochromatic regions and likely have given rise to satellite DNAs, which are not active genes. These data show the variability of rDNA within karyotypes of the genus Capsicum, providing anchor points for (comparative) genetic maps. In addition, the obtained information might be useful for studies on evolution of repetitive DNA.5995-11

Genetic requirements for infection-specific responses in conferring disease resistance in <i>Arabidopsis</i>

Immunity in plants arises from defense regulatory circuits that can be conceptualized as modules. Both the types (and isolates) of pathogen and the repertoire of plant receptors may cause different modules to be activated and affect the magnitude of activation. Two major defense enzymes of Arabidopsis are ALD1 and ICS1/SID2. ALD1 is an aminotransferase needed for producing the metabolites pipecolic acid, hydroxy-pipecolic acid, and possibly other defense signals. ICS1/SID2 produces isochorismate, an intermediate in the synthesis of salicylic acid (SA) and SA-derivatives. Metabolites resulting from the activation of these enzymes are found in petiole exudates and may serve as priming signals for systemic disease resistance in Arabidopsis. Mutants lacking ALD1 are known to have reduced SA accumulation. To further investigate the role of ALD1 in relation to the SA-related module, immunity phenotypes of double mutants that disrupt ALD1 and ICS1/SID2 or SA perception by NPR1 were compared with each single mutant after infection by different Pseudomonas strains. Exudates collected from these mutants after infection were also evaluated for their ability to confer disease resistance when applied to wild-type plants. During infection with virulent or attenuated strains, the loss of ALD1 does not increase the susceptibility of npr1 or sid2 mutants, suggesting the main role of ALD1 in this context is in amplifying the SA-related module. In contrast, after an infection that leads to strong pathogen recognition via the cytoplasmic immune receptor RPS2, ALD1 acts additively with both NPR1 and ICS1/SID2 to suppress pathogen growth. The additive effects are observed in early basal defense responses as well as SA-related events. Thus, there are specific conditions that dictate whether the modules independently contribute to immunity to provide additive protection during infection. In the exudate experiments, intact NPR1 and ICS1/SID2, but not ALD1 in the donor plants were needed for conferring immunity. Mixing exudates showed that loss of SID2 yields exudates that suppress active exudates from wild-type or ald1 plants. This indicates that ICS1/SID2 may not only lead to positive defense signals, but also prevent a suppressive signal(s)

The Arabidopsis chromatin regulator MOM1 is a negative component of the defense priming induced by AZA, BABA and PIP

In plants, the establishment of broad and long-lasting immunity is based on programs that control systemic resistance and immunological memory or “priming”. Despite not showing activated defenses, a primed plant induces a more efficient response to recurrent infections. Priming might involve chromatin modifications that allow a faster/stronger activation of defense genes. The Arabidopsis chromatin regulator “Morpheus Molecule 1” (MOM1) has been recently suggested as a priming factor affecting the expression of immune receptor genes. Here, we show that mom1 mutants exacerbate the root growth inhibition response triggered by the key defense priming inducers azelaic acid (AZA), β-aminobutyric acid (BABA) and pipecolic acid (PIP). Conversely, mom1 mutants complemented with a minimal version of MOM1 (miniMOM1 plants) are insensitive. Moreover, miniMOM1 is unable to induce systemic resistance against Pseudomonas sp. in response to these inducers. Importantly, AZA, BABA and PIP treatments reduce the MOM1 expression, but not miniMOM1 transcript levels, in systemic tissues. Consistently, several MOM1-regulated immune receptor genes are upregulated during the activation of systemic resistance in WT plants, while this effect is not observed in miniMOM1. Taken together, our results position MOM1 as a chromatin factor that negatively regulates the defense priming induced by AZA, BABA and PIP

Proline dehydrogenase is a positive regulator of cell death in different kingdoms

Proline dehydrogenase (ProDH) catalyzes the flavin-dependent oxidation of Pro into Δ1-pyrroline-5-carboxylate (P5C). This is the first of the two enzymatic reactions that convert proline (Pro) into glutamic acid (Glu). The P5C thus produced is non-enzymatically transformed into glutamate semialdehyde (GSA), which acts as a substrate of P5C dehydrogenase (P5CDH) to generate Glu. Activation of ProDH can generate different effects depending on the behavior of other enzymes of this metabolism. Under different conditions it can generate toxic levels of P5C, alter the cellular redox homeostasis and even produce reactive oxygen species (ROS). Recent studies indicate that in Arabidopsis, the enzyme potentiates the oxidative burst and cell death associated to the Hypersensitive Responses (HR). Interestingly, activation of ProDH can also produce harmful effects in other organisms, suggesting that the enzyme may play a conserved role in the control of cell death

Delaying surgery for patients with a previous SARS-CoV-2 infection

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