Psychometric Properties of the Spanish Version of the Parental Feeding Style Questionnaire.

BACKGROUND: There are no validated instruments in Spain for measuring parental feeding styles. The aim was to validate the Parental Feeding Styles Questionnaires (PFSQ) in a Spanish sample. METHOD: A total of 523 mothers of 523 school-children participated. The children had a mean age of 4.4 years (SD = 1.3), with 51% being boys (M = 4.3 years, SD = 1.4) and 49% girls (M = 4.5 years, = SD 1.3). The PFSQ and the Comprehensive General Parenting Styles Questionnaire (CGPQ) were used. RESULTS: A model of four correlated factors was identified: Prompting/encouraging eating, emotional feeding, instrumental feeding, and control over eating. Cronbach's alpha for the subscales ranged from 0.64 to 0.86, and McDonald's Omega coefficient ranged from 0.66 to 0.86. Emotional feeding and prompting/encouraging eating had values above 0.70, control over eating had a value of 0.68 and instrumental feeding had an alpha coefficient of 0.64 and omega coefficient of 0.66. The factor structure was similar to the original and to other adapted versions. The Spanish sample used more control over eating and prompting/encouraging to eat. CONCLUSIONS: The adapted PFSQ is a suitable instrument for assessing the feeding styles of Spanish parents.

Psychometric Properties of the Spanish Version of the Parental Feeding Style Questionnaire / Propiedades Psicométricas de la Versión Española del Cuestionario de Estilos deAlimentación Parental

Background: There are no validated instruments in Spain for measuring parental feeding styles. The aim was to validate the Parental Feeding Styles Questionnaires (PFSQ) in a Spanish sample. Method: A total of 523 mothers of 523 school-children participated. The children had a mean age of 4.4 years (SD = 1.3), with 51% being boys (M = 4.3 years, SD = 1.4) and 49% girls (M = 4.5 years, SD = 1.3). The PFSQ and the Comprehensive General Parenting Styles Questionnaire (CGPQ) were used. Results: A model of four correlated factors was identified: Prompting/encouraging eating, emotional feeding, instrumental feeding, and control over eating. Cronbach’s alpha for the subscales ranged from 0.64 to 0.86, and McDonald’s Omega coefficient ranged from 0.66 to 0.86. Emotional feeding and prompting/ encouraging eating had values above 0.70, control over eating had a value of 0.68 and instrumental feeding had an alpha coefficient of 0.64 and omega coefficient of 0.66. The factor structure was similar to the original and to other adapted versions. The Spanish sample used more control over eating and prompting/encouraging to eat. Conclusions: The adapted PFSQ is a suitable instrument for assessing the feeding styles of Spanish parents.(AU)

Antecedentes: No hay suficientes instrumentos validados en España para medir los estilos de alimentación parental. El objetivo fue validar el cuestionario de estilos de alimentación Parental (PFSQ) en muestra española. Método: Participaron 523 madres de 523 escolares con una media de edad de 4.4 años (DT = 1.3), siendo el 51% niños (M = 4.3 años, DT = 1.4) y 49% niñas (M = 4.5 años, DT=1.3). Se utilizaron el PFSQ y el cuestionario de estilos de crianza general (CGPQ). Resultados: Se identificó un modelo de cuatro factores correlacionados: persuadirle/animarle a comer, alimentación emocional, alimentación instrumental, y control de la ingesta. El alfa de Cronbach de las subescalas osciló entre 0.64 y 0.86, y el coeficiente omega de McDonald entre 0.66 y 0.86. Alimentación emocional y persuadirle/animarle a comer obtuvieron valores superiores a 0.70, control de la ingesta obtuvo 0.68 y la alimentación instrumental, un coeficiente alfa de 0.64 y un coeficiente Omega de 0.66. La estructura factorial coincide con la versión original y otras versiones adaptadas. La muestra española utilizó más el control de la ingesta y persuadirle/animarle a comer. Conclusiones: El PFSQ es un instrumento adecuado para evaluar los estilos de alimentación de los padres españoles.(AU)

PSICE Project Protocol: Evaluation of the Unified Protocol for Transdiagnostic Treatment for Adolescents with Emotional Symptoms in School Settings / El protocolo del Proyecto PSICE: evaluación del protocolo unificado transdiagnóstico para adolescentes con síntomas emocionales en contextos educativos

Background: The aim of the PSICE (Evidence-based Psychology in Educational Contexts) Project is to examine the effectiveness of the Unified Protocol for Transdiagnostic Treatment of Adolescents (UP-A) with symptoms of anxiety and depression in school settings. The goal is to prevent emotional problems and to improve adolescents’ socioemotional adjustment, learning processes, and academic performance. Method: A randomized controlled trial with two groups will be performed: active control (progressive relaxation training) and experimental (UP-A). After screening, participants with subclinical emotional symptomatology will be selected for pre- and post-test evaluation and follow-up at 6, 12, and 18 months. Results: The impact of different indicators at behavioral, cognitive, affective, social and academic functioning levels will be analyzed, as well as their effects in the short, medium and long term. Conclusions: Examining the effectiveness of the UP-A in the Spanish educational context will, among other things, provide data for informed decision-making in the field of educational psychology. In addition, it will ensure that such interventions, using standardized protocols, are accessible to a large population at such an important stage of human development as adolescence. The PSICE project will provide leadership and guidance on the importance of psychology in schools. (AU)

Antecedentes: El objetivo del Proyecto PSICE (Psicología basada en la evidencia en contextos educativos) es examinar la efectividad del protocolo unificado para el tratamiento transdiagnóstico de síntomas de ansiedad y depresión en adolescentes (UP-A) en contextos educativos. El objetivo es prevenir los problemas emocionales, así como mejorar el ajuste socioemocional, los procesos de aprendizaje y el rendimiento académico de los adolescentes. Método: Se implementa mediante un ensayo controlado aleatorizado con dos grupos: control activo (entrenamiento en relajación progresiva) y experimental (UP-A). Tras un cribado, se seleccionarán participantes con síntomas emocionales subclínicos a los que se realizará evaluación pretest, postest y seguimiento a los 6, 12 y 18 meses. Resultados: Se analizará el impacto de diferentes indicadores a nivel comportamental, cognitivo, afectivo y de funcionamiento social y académico, así como sus efectos a corto, medio y largo plazo. Conclusiones: Examinar la efectividad del UP-A en el contexto educativo español permitirá, entre otras cuestiones, disponer de datos en el campo de la psicología educativa de cara a la toma de decisiones informadas, además de garantizar que dichas intervenciones sean accesibles, empleando protocolos estandarizados, para un gran conjunto de la población y en una etapa del desarrollo humano tan relevante como es la adolescencia. El proyecto PSICE proporcionará liderazgo y orientación sobre la importancia de la Psicología en el contexto educativo. (AU)

Nonverbal Oro-Motor Exercises: Do They Really Work for Phonoarticulatory Difficulties?

Articulation disorders are deficiencies in the realization of speech sounds unrelated to organic or neurological disorders. Over the last decade, there has been a debate on the efficiency of non-verbal oro-motor exercises, which are orofacial movements programmed and organized in an intentional and coordinated way to control lips, tongue, and soft palate muscles. Of the 122 children evaluated, 52 presented articulatory difficulties. An intervention with nonverbal oro-motor exercises was applied, and children were again assessed following treatment. The results showed no differences between the experimental and control groups, either in the number of sounds that improved after this period or in the severity of difficulties (we categorized those with articulation difficulties in two to six sounds as 'medium' and those with difficulties in articulating more than seven sounds as 'severe'). These results indicated that nonverbal oro-motor exercises alone are not efficient for intervention in difficulties in the realization of sounds in 4-year-old children.

The Role of Regulation and Emotional Eating Behaviour in the Early Development of Obesity.

The purpose of our research was to explore the role of both parents' use of behavioural regulation with food and children's emotional self-regulation in young children with and without overweight/obesity. For this purpose, 123 participants (n = 62 boys and n = 61 girls) were recruited and classified into two groups by their Body Mass Index (BMI, non-overweight vs. overweight/obese) and into two age groups (four years and seven years). The children's parents/primary caregivers completed two scales of the Childhood Obesogenic Behaviours' Questionnaire (COBQ). The participants were measured and weighed to calculate their BMI to identify overweight, obesity, and non-overweight. The results showed that the means for children who were obese/overweight were significantly higher than those of children who were non-overweight for both the parents' behavioural regulation scale (non-overweight: M = 1.80, SD = 0.69; overweight/obesity: M = 2.94, SD = 0.85) and the child's emotional overeating scale (non-overweight: M = 1.47, SD = 0.56; overweight/obesity: M = 2.65, SD = 0.87). No statistically significant differences were found related to age (4 and 7 years), indicating that the potential impact of obesogenic behaviours starts early in development. Similarly, no differences by gender were found. Due to the implications of obesity for physical and mental health, and the high probability of maintaining this overweight status in the long term, family-based interventions to prevent obesity are highly advisable from birth.

Transition of a Judo Program from In-Person to Remote Delivery During COVID-19 for Youth with Autism Spectrum Disorder.

OBJECTIVES: To examine the feasibility of a remote judo program for high school students with autism spectrum disorder (ASD) during the COVID-19 pandemic. METHODS: Nine high school students with ASD had been participating in an in-person judo program that transitioned to a livestream format once the stay-at-home orders were mandated. The students completed surveys regarding their experience with the remote sessions. Their classroom teacher completed a semi-structured interview regarding the advantages and disadvantages of the remote format. RESULTS: Eight out of the nine students attended 92% of the remote classes. All nine students reported feeling satisfied with the remote judo sessions. Reported benefits of the remote format included the structured routine during the pandemic and the opportunity for physical activity. Disadvantages included a lack of space and lack of one-on-one instruction. CONCLUSIONS: The remote judo program appeared to be both feasible and acceptable for youth with ASD.

Small Molecule DFPM Derivative-Activated Plant Resistance Protein Signaling in Roots Is Unaffected by EDS1 Subcellular Targeting Signal and Chemical Genetic Isolation of victr R-Protein Mutants.

The small molecule DFPM ([5-(3,4-dichlorophenyl)furan-2-yl]-piperidine-1-ylmethanethione) was recently shown to trigger signal transduction via early effector-triggered immunity signaling genes including EDS1 and PAD4 in Arabidopsis thaliana accession Col-0. Chemical genetic analyses of A. thaliana natural variants identified the plant Resistance protein-like Toll/Interleukin1 Receptor (TIR)-Nucleotide Binding (NB)-Leucine-Rich Repeat (LRR) protein VICTR as required for DFPM-mediated root growth arrest. Here a chemical genetic screen for mutants which disrupt DFPM-mediated root growth arrest in the Col-0 accession identified new mutant alleles of the TIR-NB-LRR gene VICTR. One allele, victr-6, carries a Gly216-to-Asp mutation in the Walker A domain supporting an important function of the VICTR nucleotide binding domain in DFPM responses consistent with VICTR acting as a canonical Resistance protein. The essential nucleo-cytoplasmic regulator of TIR-NB-LRR-mediated effector-triggered immunity, EDS1, was reported to have both nuclear and cytoplasmic actions in pathogen resistance. DFPM was used to investigate the requirements for subcellular EDS1 localization in DFPM-mediated root growth arrest. EDS1-YFP fusions engineered to localize mainly in the cytoplasm or the nucleus by tagging with a nuclear export signal (NES) or a nuclear localization signal (NLS), respectively, were tested. We found that wild-type EDS1-YFP and both the NES and NLS-tagged EDS1 variants were induced by DFPM treatments and fully complemented eds1 mutant plants in root responses to DFPM, suggesting that enrichment of EDS1 in either compartment could confer DFPM-mediated root growth arrest. We further found that a light and O2-dependent modification of DFPM is necessary to mediate DFPM signaling in roots. Chemical analyses including Liquid Chromatography-Mass Spectrometry and High-Resolution Atmospheric Pressure Chemical Ionization Mass Spectrometry identified a DFPM modification product that is likely responsible for bioactivity mediating root growth arrest. We propose a chemical structure of this product and a possible reaction mechanism for DFPM modification.

Arabidopsis thaliana DM2h (R8) within the Landsberg RPP1-like Resistance Locus Underlies Three Different Cases of EDS1-Conditioned Autoimmunity.

Plants have a large panel of nucleotide-binding/leucine rich repeat (NLR) immune receptors which monitor host interference by diverse pathogen molecules (effectors) and trigger disease resistance pathways. NLR receptor systems are necessarily under tight control to mitigate the trade-off between induced defenses and growth. Hence, mis-regulated NLRs often cause autoimmunity associated with stunting and, in severe cases, necrosis. Nucleocytoplasmic ENHANCED DISEASE SUSCEPTIBILITY1 (EDS1) is indispensable for effector-triggered and autoimmune responses governed by a family of Toll-Interleukin1-Receptor-related NLR receptors (TNLs). EDS1 operates coincidently or immediately downstream of TNL activation to transcriptionally reprogram cells for defense. We show here that low levels of nuclear-enforced EDS1 are sufficient for pathogen resistance in Arabidopsis thaliana, without causing negative effects. Plants expressing higher nuclear EDS1 amounts have the genetic, phenotypic and transcriptional hallmarks of TNL autoimmunity. In a screen for genetic suppressors of nuclear EDS1 autoimmunity, we map multiple, independent mutations to one gene, DM2h, lying within the polymorphic DANGEROUS MIX2 cluster of TNL RPP1-like genes from A. thaliana accession Landsberg erecta (Ler). The DM2 locus is a known hotspot for deleterious epistatic interactions leading to immune-related incompatibilities between A. thaliana natural accessions. We find that DM2hLer underlies two further genetic incompatibilities involving the RPP1-likeLer locus and EDS1. We conclude that the DM2hLer TNL protein and nuclear EDS1 cooperate, directly or indirectly, to drive cells into an immune response at the expense of growth. A further conclusion is that regulating the available EDS1 nuclear pool is fundamental for maintaining homeostatic control of TNL immune pathways.

Brain functional connectivity changes in children that differ in impulsivity temperamental trait.

Impulsivity is a core personality trait forming part of normal behavior and contributing to adaptive functioning. However, in typically developing children, altered patterns of impulsivity constitute a risk factor for the development of behavioral problems. Since both pathological and non-pathological states are commonly characterized by continuous transitions, we used a correlative approach to investigate the potential link between personality and brain dynamics. We related brain functional connectivity of typically developing children, measured with magnetic resonance imaging at rest, with their impulsivity scores obtained from a questionnaire completed by their parents. We first looked for areas within the default mode network (DMN) whose functional connectivity might be modulated by trait impulsivity. Then, we calculated the functional connectivity among these regions and the rest of the brain in order to assess if impulsivity trait altered their relationships. We found two DMN clusters located at the posterior cingulate cortex and the right angular gyrus which were negatively correlated with impulsivity scores. The whole-brain correlation analysis revealed the classic network of correlating and anti-correlating areas with respect to the DMN. The impulsivity trait modulated such pattern showing that the canonical anti-phasic relation between DMN and action-related network was reduced in high impulsive children. These results represent the first evidence that the impulsivity, measured as personality trait assessed through parents' report, exerts a modulatory influence over the functional connectivity of resting state brain networks in typically developing children. The present study goes further to connect developmental approaches, mainly based on data collected through the use of questionnaires, and behavioral neuroscience, interested in how differences in brain structure and functions reflect in differences in behavior.

Salmonella enterica induces and subverts the plant immune system.

Infections with Salmonella enterica belong to the most prominent causes of food poisoning and infected fruits and vegetables represent important vectors for salmonellosis. Although it was shown that plants raise defense responses against Salmonella, these bacteria persist and proliferate in various plant tissues. Recent reports shed light into the molecular interaction between plants and Salmonella, highlighting the defense pathways induced and the means used by the bacteria to escape the plant immune system and accomplish colonization. It was recently shown that plants detect Salmonella pathogen-associated molecular patterns (PAMPs), such as the flagellin peptide flg22, and activate hallmarks of the defense program known as PAMP-triggered immunity (PTI). Interestingly, certain Salmonella strains carry mutations in the flg22 domain triggering PTI, suggesting that a strategy of Salmonella is to escape plant detection by mutating PAMP motifs. Another strategy may rely on the type III secretion system (T3SS) as T3SS mutants were found to induce stronger plant defense responses than wild type bacteria. Although Salmonella effector delivery into plant cells has not been shown, expression of Salmonella effectors in plant tissues shows that these bacteria also possess powerful means to manipulate the plant immune system. Altogether, these data suggest that Salmonella triggers PTI in plants and evolved strategies to avoid or subvert plant immunity.

Plants as alternative hosts for Salmonella.

Recent findings show that many human pathogenic bacteria can use multiple host organisms. For example, Salmonella Typhimurium can use plants as alternative hosts to humans and other animals. These bacteria are able to adhere to plant surfaces and actively infect the interior of plants. Similarly to the infection of animal cells, S. Typhimurium suppresses plant defense responses by a type III secretion mechanism, indicating that these bacteria possess a dedicated multi-kingdom infection strategy, raising the question of host specificity. In addition, evidence is accumulating that the interaction of Salmonella with plants is an active process with different levels of specificity, because different Salmonella serovars show variations in pathogenicity, and different plant species reveal various levels of resistance towards these bacteria.

AGC kinases in plant development and defense.

More than 100,000 publications demonstrate that AGC kinases are important regulators of growth, metabolism, proliferation, cell divison, survival and apoptosis in mammalian systems. Mutation and/or dysregulation of these kinases contribute to the pathogenesis of many human diseases, including cancer and diabetes. Although AGC kinases are also present in plants, little is known about their functions. We demonstrated that the AGC kinase OXIDATIVE SIGNAL-INDUCIBLE 1 (OXI1/AGC2-1) regulate important developmental processes and defense responses in plants. The summary of recent progress also demonstrates that we are only beginning to understand the role of this kinase pathway in plants.

Conservation of Salmonella infection mechanisms in plants and animals.

Salmonella virulence in animals depends on effectors injected by Type III Secretion Systems (T3SSs). In this report we demonstrate that Salmonella mutants that are unable to deliver effectors are also compromised in infection of Arabidopsis thaliana plants. Transcriptome analysis revealed that in contrast to wild type bacteria, T3SS mutants of Salmonella are compromised in suppressing highly conserved Arabidopsis genes that play a prominent role during Salmonella infection of animals. We also found that Salmonella originating from infected plants are equally virulent for human cells and mice. These results indicate a high degree of conservation in the defense and infection mechanism of animal and plant hosts during Salmonella infection.

Anticipatory reaching of seven- to eleven-month-old infants in occlusion situations.

The present study examined 7- to 11-month-old infants' anticipatory and reactive reaching for temporarily occluded objects. Infants were presented with laterally approaching objects that moved at different velocities (10, 20, and 40 cm/s) in different occlusion situations (no-, 20 cm-, and 40 cm-occlusion), resulting in occlusion durations ranging between 0 and 4s. Results show that except for object velocity and occlusion distance, occlusion duration was a critical constraint for infants' reaching behaviors. We found that the older infants reached more often, but that an increase in occlusion duration resulted in a decline in reaching frequency that was similar across age groups. Anticipatory reaching declined with increasing occlusion duration, but the adverse effects for longer occlusion durations diminished with age. It is concluded that with increasing age infants are able to retain and use information to guide reaching movements over longer periods of non-visibility, providing support for the graded representation hypothesis (Jonsson & von Hofsten, 2003) and the two-visual systems model (Milner & Goodale, 1995).

Natural variation at Strubbelig Receptor Kinase 3 drives immune-triggered incompatibilities between Arabidopsis thaliana accessions.

Accumulation of genetic incompatibilities within species can lead to reproductive isolation and, potentially, speciation. In this study, we show that allelic variation at SRF3 (Strubbelig Receptor Family 3), encoding a receptor-like kinase, conditions the occurrence of incompatibility between Arabidopsis thaliana accessions. The geographical distribution of SRF3 alleles reveals that allelic forms causing epistatic incompatibility with a Landsberg erecta allele at the RPP1 resistance locus are present in A. thaliana accessions in central Asia. Incompatible SRF3 alleles condition for an enhanced early immune response to pathogens as compared to the resistance-dampening effect of compatible SRF3 forms in isogenic backgrounds. Variation in disease susceptibility suggests a basis for the molecular patterns of a recent selective sweep detected at the SRF3 locus in central Asian populations.

Balanced nuclear and cytoplasmic activities of EDS1 are required for a complete plant innate immune response.

An important layer of plant innate immunity to host-adapted pathogens is conferred by intracellular nucleotide-binding/oligomerization domain-leucine rich repeat (NB-LRR) receptors recognizing specific microbial effectors. Signaling from activated receptors of the TIR (Toll/Interleukin-1 Receptor)-NB-LRR class converges on the nucleo-cytoplasmic immune regulator EDS1 (Enhanced Disease Susceptibility1). In this report we show that a receptor-stimulated increase in accumulation of nuclear EDS1 precedes or coincides with the EDS1-dependent induction and repression of defense-related genes. EDS1 is capable of nuclear transport receptor-mediated shuttling between the cytoplasm and nucleus. By enhancing EDS1 export from inside nuclei (through attachment of an additional nuclear export sequence (NES)) or conditionally releasing EDS1 to the nucleus (by fusion to a glucocorticoid receptor (GR)) in transgenic Arabidopsis we establish that the EDS1 nuclear pool is essential for resistance to biotrophic and hemi-biotrophic pathogens and for transcriptional reprogramming. Evidence points to post-transcriptional processes regulating receptor-triggered accumulation of EDS1 in nuclei. Changes in nuclear EDS1 levels become equilibrated with the cytoplasmic EDS1 pool and cytoplasmic EDS1 is needed for complete resistance and restriction of host cell death at infection sites. We propose that coordinated nuclear and cytoplasmic activities of EDS1 enable the plant to mount an appropriately balanced immune response to pathogen attack.

Nucleoporin MOS7/Nup88 contributes to plant immunity and nuclear accumulation of defense regulators.

Controlled nucleocytoplasmic trafficking is an important feature for fine-tuning signaling pathways in eukaryotic organisms. Nuclear pore complexes (NPCs) composed of nucleoporin proteins (Nups) are essential for the exchange of macromolecules across the nuclear envelope. A recent genetic screen in our laboratory identified a partial loss-of-function mutation in Arabidopsis MOS7/Nup88 that causes defects in basal immunity, Resistance (R) protein-mediated defense and systemic acquired resistance. In Drosophila and mammalian cells, exportin-mediated nuclear export of activated Rel/NFκB transcription factors is enhanced in nup88 mutants resulting in immune response failure. Consistent with Nup88 promoting nuclear retention of NFκB, our functional analyses revealed that MOS7/Nup88 is required for appropriate nuclear accumulation of the autoactivated R protein snc1, as well as the key immune regulators EDS1 and NPR1. These results suggest that controlling the nuclear concentrations of specific immune regulators is fundamental for defining defense outputs.

Heaven's Gate: nuclear accessibility and activities of plant immune regulators.

Proper deciphering of abiotic and biotic stresses is essential for plant survival and requires plasticity in response pathway activation. Environmental stress signals are ultimately integrated and transcriptional programs defined inside the nucleus. In animal and plant immunity, various mechanisms help to constrain the activities of transcriptional regulators and transcription factors until an appropriate stimulus releases them from inactive complexes in the cytoplasm, nucleoplasm or at the chromatin to modulate gene expression. Controlling the transport of macromolecules to and from the nucleus and dynamic rearrangements of chromatin-associated transcription complexes emerge as key regulatory processes, permitting flexibility of the plant response to a fluctuating environment with varying pathogen pressure.

Nuclear pore complex component MOS7/Nup88 is required for innate immunity and nuclear accumulation of defense regulators in Arabidopsis.

Plant immune responses depend on dynamic signaling events across the nuclear envelope through nuclear pores. Nuclear accumulation of certain resistance (R) proteins and downstream signal transducers are critical for their functions, but it is not understood how these processes are controlled. Here, we report the identification, cloning, and analysis of Arabidopsis thaliana modifier of snc1,7 (mos7-1), a partial loss-of-function mutation that suppresses immune responses conditioned by the autoactivated R protein snc1 (for suppressor of npr1-1, constitutive 1). mos7-1 single mutant plants exhibit defects in basal and R protein-mediated immunity and in systemic acquired resistance but do not display obvious pleiotropic defects in development, salt tolerance, or plant hormone responses. MOS7 is homologous to human and Drosophila melanogaster nucleoporin Nup88 and resides at the nuclear envelope. In animals, Nup88 attenuates nuclear export of activated NF-kappaB transcription factors, resulting in nuclear accumulation of NF-kappaB. Our analysis shows that nuclear accumulation of snc1 and the defense signaling components Enhanced Disease Susceptibility 1 and Nonexpresser of PR genes 1 is significantly reduced in mos7-1 plants, while nuclear retention of other tested proteins is unaffected. The data suggest that specifically modulating the nuclear concentrations of certain defense proteins regulates defense outputs.

Incremental steps toward incompatibility revealed by Arabidopsis epistatic interactions modulating salicylic acid pathway activation.

Plant growth is influenced by genetic factors and environmental cues. Genotype-by-environment interactions are governed by complex genetic epistatic networks that are subject to natural selection. Here we describe a novel epistatic interaction modulating growth in response to temperature common to 2 Arabidopsis recombinant inbred line (RIL) populations (Ler x Kas-2 and Ler x Kond). At 14 degrees C, lines with specific allele combinations at interacting loci (incompatible interactions) have severe growth defects. These lines exhibit deregulated cell death programs and enhanced disease resistance. At 20 degrees C, growth defects are suppressed, but a positive trait of enhanced resistance is retained. Mapping of 1 interacting QTL to a cluster of RPP1-like TIR-NB-LRR genes on chromosome 3 is consistent with our finding that environmentally conditioned epistasis depends on activation of the salicylic acid (SA) stress signaling pathway. The nature of the epistatic interaction conforms to the Dobzhansky-Muller model of genetic incompatibility with incomplete penetrance for reproductive isolation. Variation in fitness of different incompatible lines reveals the presence of additional modifiers in the genetic background. We propose that certain interacting loci lead to an optimal balance between growth and resistance to pathogens by modulating SA signaling under specific environments. This could allow the accumulation of additional incompatibilities before reaching complete reproductive isolation.