Enviromic-based kernels may optimize resource allocation with multi-trait multi-environment genomic prediction for tropical Maize.

BACKGROUND: Success in any genomic prediction platform is directly dependent on establishing a representative training set. This is a complex task, even in single-trait single-environment conditions and tends to be even more intricated wherein additional information from envirotyping and correlated traits are considered. Here, we aimed to design optimized training sets focused on genomic prediction, considering multi-trait multi-environment trials, and how those methods may increase accuracy reducing phenotyping costs. For that, we considered single-trait multi-environment trials and multi-trait multi-environment trials for three traits: grain yield, plant height, and ear height, two datasets, and two cross-validation schemes. Next, two strategies for designing optimized training sets were conceived, first considering only the genomic by environment by trait interaction (GET), while a second including large-scale environmental data (W, enviromics) as genomic by enviromic by trait interaction (GWT). The effective number of individuals (genotypes × environments × traits) was assumed as those that represent at least 98% of each kernel (GET or GWT) variation, in which those individuals were then selected by a genetic algorithm based on prediction error variance criteria to compose an optimized training set for genomic prediction purposes. RESULTS: The combined use of genomic and enviromic data efficiently designs optimized training sets for genomic prediction, improving the response to selection per dollar invested by up to 145% when compared to the model without enviromic data, and even more when compared to cross validation scheme with 70% of training set or pure phenotypic selection. Prediction models that include G × E or enviromic data + G × E yielded better prediction ability. CONCLUSIONS: Our findings indicate that a genomic by enviromic by trait interaction kernel associated with genetic algorithms is efficient and can be proposed as a promising approach to designing optimized training sets for genomic prediction when the variance-covariance matrix of traits is available. Additionally, great improvements in the genetic gains per dollar invested were observed, suggesting that a good allocation of resources can be deployed by using the proposed approach.

Metabolomic exhibits different profiles and potential biomarkers of Vitis spp. co-cultivated with Fusarium oxysporum for short, medium, and long times.

Differential rootstock tolerance to Fusarium spp. supports viticulture worldwide. However, how plants stand against the fungus still needs to be explored. We hypothesize it involves a differential metabolite modulation. Thus, we performed a gas chromatography coupled with mass spectrometry (GC-MS) analysis of Paulsen P1103 and BDMG573 rootstocks, co-cultured with Fusarium oxysporum (FUS) for short, medium, and long time (0, 4, and 8 days after treatment [DAT]). In shoots, principal component analysis (PCA) showed a complete overlap between BDMG573 non-co-cultivated and FUS at 0 DAT, and P1103 treatments showed a slight overlap at both 4 and 8 DAT. In roots, PCA exhibited overlapping between BDMG573 treatments at 0 DAT, while P1103 treatments showed overlapping at 0 and 4 DAT. Further, there is a complete overlapping between BDMG573 and P1103 FUS profiles at 8 DAT. In shoots, 1,3-dihydroxyacetone at 0 and 4 DAT and maltose at 4 and 8 DAT were biomarkers for BDMG573. For P1103, glyceric acid, proline, and sorbitol stood out at 0, 4, and 8 DAT, respectively. In BDMG573 roots, the biomarkers were ß-alanine at 0 DAT, cellobiose and sorbitol at both 4 and 8 DAT. While in P1103 roots, they were galactose at 0 and 4 DAT and 1,3-dihydroxyacetone at 8 DAT. Overall, there is an increase in amino acids, glycolysis, and tricarboxylic acid components in tolerant Paulsen P1103 shoots. Thus, it provides a new perspective on the primary metabolism of grapevine rootstocks to F. oxysporum that may contribute to strategies for genotype tolerance and early disease identification.

Peak height velocity in young athletes: A longitudinal meta-analysis.

The present longitudinal meta-analysis aimed to estimate the growth curves and age at peak height velocity (PHV) in young male athletes, considering anthropometric data from available longitudinal studies. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, studies with repeated measurements in young male athletes were identified from searches across four databases (MEDLINE, SPORTDiscus, Web of Science, and SCOPUS). Estimations were based on multilevel polynomial models using a fully Bayesian framework. After a full-text screening of 317 studies meeting the eligibility criteria, 31 studies were considered. Studies were excluded mainly due to study design, repeated reporting, and incomplete reporting of the outcomes. Of the 31 studies analysed, 26 (84%) focused on young European athletes. The average age at PHV for the total sample of studies with young athletes was 13.1 years (90% credible interval: 12.9; 13.4). When considering data by sport, there was substantial variation in the age at PHV estimates (range: 12.4 to 13.5 years). As most studies in the meta-analysis focused on young European football players (52%), predictions for young athletes from other sports may be limited. The age at PHV in the available data occurred earlier than in general paediatric populations.

Population-tailored mock genome enables genomic studies in species without a reference genome.

Based on molecular markers, genomic prediction enables us to speed up breeding schemes and increase the response to selection. There are several high-throughput genotyping platforms able to deliver thousands of molecular markers for genomic study purposes. However, even though its widely applied in plant breeding, species without a reference genome cannot fully benefit from genomic tools and modern breeding schemes. We used a method to assemble a population-tailored mock genome to call single-nucleotide polymorphism (SNP) markers without an available reference genome, and for the first time, we compared the results with standard genotyping platforms (array and genotyping-by-sequencing (GBS) using a reference genome) for performance in genomic prediction models. Our results indicate that using a population-tailored mock genome to call SNP delivers reliable estimates for the genomic relationship between genotypes. Furthermore, genomic prediction estimates were comparable to standard approaches, especially when considering only additive effects. However, mock genomes were slightly worse than arrays at predicting traits influenced by dominance effects, but still performed as well as standard GBS methods that use a reference genome. Nevertheless, the array-based SNP markers methods achieved the best predictive ability and reliability to estimate variance components. Overall, the mock genomes can be a worthy alternative for genomic selection studies, especially for those species where the reference genome is not available.

Genotyping marker density and prediction models effects in long-term breeding schemes of cross-pollinated crops.

KEY MESSAGE: In genomic recurrent selection, the more markers, the better because they buffer the linkage disequilibrium losses caused by recombination over cycles, and consequently, provide higher responses to selection. Reductions of genotyping marker density have been extensively evaluated as potential strategies to reduce the genotyping costs of genomic selection (GS). Low-density marker panels are appealing in GS because they entail lower multicollinearity and computing time and allow more individuals to be genotyped for the same cost. However, statistical models used in GS are usually evaluated with empirical data, using "static" training sets and populations. This may be adequate for making predictions during a breeding program's initial cycles but not for the long-term. Moreover, studies that focus on long selective breeding cycles generally do not consider GS models with the effect of dominance, which is particularly important for breeding outcomes in cross-pollinated crops. Hence, dominance effects are important and unexplored in GS for long-term programs involving allogamous species. To address it, we employed two approaches: analysis of empirical maize datasets and simulations of long-term breeding applying phenotypic and genomic recurrent selection (intrapopulation and reciprocal schemes). In both schemes, we simulated twenty breeding cycles and assessed the effect of marker density reduction on the population mean, the best crosses, additive variance, selective accuracy, and response to selection with models [additive, additive-dominant, general (GCA), and this plus specific combining ability (GCA + SCA)]. Our results indicate that marker reduction based on linkage disequilibrium levels provides useful predictions only within a cycle, as accuracy significantly decreases over cycles. In the long-term, without training set updating, high-marker density provides the best responses to selection. The model to be used depends on the breeding scheme: additive for intrapopulation and additive-dominant or GCA + SCA for reciprocal.

H2O2 priming induces proteomic responses to defense against salt stress in maize.

KEY MESSAGE: H2O2 priming reprograms essential proteins' expression to help plants survive, promoting responsive and unresponsive proteins adjustment to salt stress. ABSTACRT: Priming is a powerful strategy to enhance abiotic stress tolerance in plants. Despite this, there is scarce information about the mechanisms induced by H2O2 priming for salt stress tolerance, particularly on proteome modulation. Improving maize cultivation in areas subjected to salinity is imperative for the local economy and food security. Thereby, this study aimed to investigate physiological changes linked with post-translational protein events induced by foliar H2O2 priming of Zea mays plants under salt stress. As expected, salt treatment promoted a considerable accumulation of Na+ ions, a 12-fold increase. It drastically affected growth parameters and relative water content, as well as promoted adverse alteration in the proteome profile, when compared to the absence of salt conditions. Conversely, H2O2 priming was beneficial via specific proteome reprogramming, which promoted better response to salinity by 16% reduction in Na+ content and shoots growth improvement, increasing 61% in dry mass. The identified proteins were associated with photosynthesis and redox homeostasis, critical metabolic pathways for helping plants survive in saline stress by the protection of chloroplasts organization and carbon fixation, as well as state redox. This research provides new proteomic data to improve understanding and forward identifying biotechnological strategies to promote salt stress tolerance.

On the genetic architecture in a public tropical maize panel of the symbiosis between corn and plant growth-promoting bacteria aiming to improve plant resilience.

Exploring the symbiosis between plants and plant growth-promoting bacteria (PGPB) is a new challenge for sustainable agriculture. Even though many works have reported the beneficial effects of PGPB in increasing plant resilience for several stresses, its potential is not yet widely explored. One of the many reasons is the differential symbiosis performance depending on the host genotype. This opens doors to plant breeding programs to explore the genetic variability and develop new cultivars with higher responses to PGPB interaction and, therefore, have higher resilience to stress. Hence, we aimed to study the genetic architecture of the symbiosis between PGPB and tropical maize germplasm, using a public association panel and its impact on plant resilience. Our findings reveal that the synthetic PGPB population can modulate and impact root architecture traits and improve resilience to nitrogen stress, and 37 regions were significant for controlling the symbiosis between PGPB and tropical maize. In addition, we found two overlapping SNPs in the GWAS analysis indicating strong candidates for further investigations. Furthermore, genomic prediction analysis with genomic relationship matrix computed using only significant SNPs obtained from GWAS analysis substantially increased the predictive ability for several traits endorsing the importance of these genomic regions for the response of PGPB. Finally, the public tropical panel reveals a significant genetic variability to the symbiosis with the PGPB and can be a source of alleles to improve plant resilience. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-021-01257-6.

Genetic relationships and polyploid origins in the Lippia alba complex.

PREMISE: Plant genomes vary in size and complexity due in part to polyploidization. Latitudinal analyses of polyploidy are biased toward floras of temperate regions, with much less research done in the tropics. Lippia alba has been described as a tropical polyploid complex with diploid, triploid, tetraploid, and hexaploid accessions. However, no data regarding relationships among the ploidal levels and their origins have been reported. Our goals are to clarify the relationships among accessions of Lippia alba and the origins of each ploidal level. METHODS: We investigated 98 samples representing all five geographical regions of Brazil and all ploidal levels using microsatellite (SSR) allelic variation and DNA sequences of ITS and trnL-F. Nine morphological structures were analyzed from 33 herbarium samples, and the chemical compounds of 78 accessions were analyzed by GC-MS. RESULTS: Genetic distance analysis, the alignment block pattern, as well as RAxML and Bayesian trees showed that accessions grouped by ploidal level. The triploids form a well-defined group that originated from a single group of diploids. The tetraploids and hexaploid grouped together in SSR and trnL-F analyses. The recovered groups agree with chemical data and morphology. CONCLUSIONS: The accessions grouped by ploidal level. Only one origin of triploids from a single group of diploids was observed. The tetraploid origin is uncertain; however, it appears to have contributed to the origin of the hexaploid. This framework reveals linkages among the ploidal levels, providing new insights into the evolution of a polyploid complex of tropical plants.

Performance, motivation, and enjoyment in young female basketball players: An interdisciplinary approach.

The purpose of this study was to examine the variation in accumulated basketball training experience, body size, functional performance, deliberate practice motivation, achievement and competitiveness motivation and sources of enjoyment among young female basketball players, partitioning the potential variation by individuals´ biological characteristics (menarche status) and contextual characteristics (competitive age group and competitive level). We considered 114 adolescent female basketball players aged 14.3 (1.8) years. We used multilevel regression and poststratification estimations. The adolescent female basketball players selected for state-level had more accumulated experience, were taller and with better functional performance. Conditional on the data, youth female coaches tend to value (probably overvalue) size and function when selecting/promoting players, even at early age groups, likely contributing to an overrepresentation of early maturing girls in at early age groups. Players from club- and state-level were similarly highly motivated for deliberate practice and to achievement. Only for competitiveness, state-level players had higher values than club level players. The sources of enjoyment were influenced by context (competitive levels) for self-referenced competencies and others-referenced competencies. Structured programs of training and competition in youth female basketball provide a nurturing environment for the development of players´ engagement and commitment to training and excellence attainment.

Determinants of drop-out in youth basketball: an interdisciplinary approach.

Using an interdisciplinary approach, we examined the baseline variation in biological maturity status, training experience, body size, functional capacities (Line Drill test and Yo-Yo Intermittent Recovery level 1 test) and motivation for achievement, competitiveness and deliberate practice of youth basketball players according to their participation status in the sport two years after assessment. Fifty-seven players were considered (10.5 to 15.5 years). Two years later we ascertained whether players discontinued participation (dropout), or remained playing engaged within a structured basketball training program. Taller adolescent players were more likely to be selected/promoted in youth basketball regardless of their lower functional capacity. Achievement and competitiveness motivation (will to excel and competitiveness) were related to dropping out or persisting in this sample of youth basketball players. Overall, there is a need to consider the interaction between physical growth, biological maturation, functional capacities and behavioural characteristics, specifically among players on the path to sport expertise.

Salt acclimation in sorghum plants by exogenous proline: physiological and biochemical changes and regulation of proline metabolism.

KEY MESSAGE: Mitigation of deleterious effects of salinity promoted by exogenous proline can be partially explained by changes in proline enzymatic metabolism and expression of specific proline-related genes. Proline accumulation is a usual response to salinity. We studied the ability of exogenous proline to mitigate the salt harmful effects in sorghum (Sorghum bicolor) leaves. Ten-day-old plants were cultivated in Hoagland's nutrient solution in either the absence or presence of salinity (NaCl at 75 mM) and sprayed with distilled water or 30 mM proline solution. Salinity deleterious effects were alleviated by exogenous proline 14 days after treatment, with a return in growth and recovery of leaf area and photosynthetic parameters. Part of the salinity response reflected an improvement in ionic homeostasis, provided by reduction in Na+ and Cl- ions and increases in K+ and Ca2+ ions as well as increases of compatible solutes. In addition, the application of proline decreased membrane damage and did not increase relative water content. Proline-treated salt-stressed plants displayed increase in proline content, a response counterbalanced by punctual modulation in proline synthesis (down-regulation of Δ1-pyrroline-5-carboxylate synthetase activity) and degradation (up-regulation of proline dehydrogenase activity) enzymes. These responses were correlated with expression of specific proline-related genes (p5cs1 and prodh). Our findings clearly show that proline treatment results in favorable changes, reducing salt-induced damage and improving salt acclimation in sorghum plants.

Modeling the Angle-Specific Isokinetic Hamstring to Quadriceps Ratio Using Multilevel Generalized Additive Models.

Background and Objectives: This study considered the use of a generalized additive multilevel model to describe the joint-angle-specific functional hamstring to quadriceps ratio (H:Q ratio) in the knee, using all of the available truly isokinetic data within the range. Materials and Methods: Thirty healthy male basketball players aged 15.0 (1.4) years (average stature = 180.0 cm, SD = 11.1 cm; average body mass = 71.2, SD = 14.9 kg) years were considered. All players considered had no history of lower extremity musculoskeletal injury at the time of testing or during the 6 months before testing, and had been engaged in formal basketball training and competition for 5.9 (2.4) years. Moments of force of the reciprocal concentric and eccentric muscular actions for the knee extensors and flexors assessed by isokinetic dynamometry at 60°âˆ™s-1 were used. Results: Maximum moments of force were attained at different angle positions for knee extension. For knee flexion, it was apparent that there was an ability to maintain high levels of moment of force between 30° and 60° in the concentric muscular action, corresponding to the concentric action of the hamstrings. However, for the eccentric knee flexion, corresponding to the quadriceps action, there was a marked peak of moment of force at about 55°. The functional H:Q ratio for the knee extension was non-linear, remaining higher than 1.0 (i.e., point of equality) from the beginning of the extension until approximately 40° of the knee extension, leveling off below the point of equality thereafter. On average, the functional H:Q ratio for the knee flexion did not attain 1.0 across the range of motion. The functional H:Q ratio for the knee in the present sample peaked at 20° and 80°, declining between these angle positions to below 0.50 at about 0.54. Conclusions: Estimating the form of the non-linear relationship on-the-fly using a generalized additive multilevel model provides joint-angle-specific curves and joint-angle-specific functional H:Q ratio patterns, allowing the identification and monitoring of strength development, with potential implications for injury and performance.

Effects of Physical Exercise on the Stereotyped Behavior of Children with Autism Spectrum Disorders.

Background and Objectives: Recent studies have shown the existence of a positive relationship between physical exercise, symptomatic improvement, and reduction of damage caused by comorbidities associated with autistic spectrum disorder (ASD) in children, adolescents, and adults. The aim of this systematic review with meta-analysis (SRM) was to estimate the effects of physical exercise (PE) on the stereotyped behaviors of children with a diagnosis of ASD in intervention studies. Materials and Methods: The design followed the PRISMA guidelines and the TREND statement to assess the quality of information in each study. Nine non-randomized intervention trial studies with low, moderate, and vigorous physical exercise, with a duration varying from 8 to 48 weeks and a frequency of 3 times a week, were included in the SRM. The dependent variable episodes of stereotypical behaviors was analyzed in all studies and assessed as the number of episodes demonstrated by the child in pre- versus post-exercise intervention conditions. Results: The eight studies included a total 129 children (115 males and 14 females) with an average age of 8.93 ± 1.69 years. Children with ASD showed a reduction of 1.1 in the number of occurrences of stereotypical behaviors after intervention with physical exercise. Conclusion: Evidence was found to support physical exercise as an effective tool in reducing the number of episodes of stereotypical behaviors in children diagnosed with ASD.

Downregulation of HIF complex in the hypothalamus exacerbates diet-induced obesity.

Hypothalamic hypoxia-inducible factor-1 (HIF-1) can regulate whole-body energy homeostasis in response to changes in blood glucose, suggesting that it acts as a sensor for systemic energy stores. Here, we hypothesized that hypothalamic HIF-1 could be affected by diet-induced obesity (DIO). We used eight-week old, male C57Bl6 mice, fed normal chow diet or with high fat diet for 1, 3, 7, 14 and 28 days. The expression of HIF-1alpha and HIF-1beta was measured by PCR and western blotting and its hypothalamic distribution was evaluated by fluorescence microscopy. Inhibition of HIF-1beta in arcuate nucleus of hypothalamus was performed using stereotaxic injection of shRNA lentiviral particles and animals were grouped under normal chow diet or high fat diet for 14 days. Using bioinformatics, we show that in humans, the levels of HIF-1 transcripts are directly correlated with those of hypothalamic transcripts for proteins involved in inflammation, regulation of apoptosis, autophagy, and the ubiquitin/proteasome system; furthermore, in rodents, hypothalamic HIF-1 expression is directly correlated with the phenotype of increased energy expenditure. In mice, DIO was accompanied by increased HIF-1 expression. The inhibition of hypothalamic HIF-1 by injection of an shRNA resulted in a further increase in body mass, a decreased basal metabolic rate, increased hypothalamic inflammation, and glucose intolerance. Thus, hypothalamic HIF-1 is increased during DIO, and its inhibition worsens the obesity-associated metabolic phenotype. Thus, hypothalamic HIF-1 emerges as a target for therapeutic intervention against obesity.

Growth, functional capacities and motivation for achievement and competitiveness in youth basketball: an interdisciplinary approach.

The interaction of multiple influences on the path to sport success is not yet fully understood by sport scientists. In this study, we examined variation in body size, functional capacities and motivation for achievement, competitiveness and deliberate practice of youth basketball players associated with differences in biological maturity status, chronological age and years of training experience. Reflecting the importance of interactive effects, we examined the relationships between the psychological variables and functional capacities. Fifty-eight male basketball players aged 9.5 to 15.5 years were considered. Variables included chronological age, estimated age at peak height velocity, stature, body mass and sitting height by anthropometry; the Work and Family Orientation and Deliberate Practice Motivation Questionnaires were also used. Finally, the Line Drill test and Yo-Yo Intermittent Recovery level 1 (Yo-Yo IR1) tests were used as functional capacities indicators for basketball. Variance components models derived from series of multilevel linear regression models revealed a substantial variation by maturity status for body size, functional capacities indicators, mastery and will to excel. The influence of estimated maturity status on mastery and will to excel was independent of age and years of experience. In contrast, no relationships were observed between psychological variables and functional capacities indicators. We conclude that growth-related changes are relevant to understanding players´ motivations for achievement, competitiveness and deliberate practice. This should be of interest to those involved in the selection and development of youth basketball players.

Acute Hematological and Inflammatory Responses to High-intensity Exercise Tests: Impact of Duration and Mode of Exercise.

The purpose of this study was to investigate the hematological and inflammatory responses to 4 maximal high-intensity protocols, considering energy expenditure in each test. 9 healthy volunteers performed 4 high-intensity exercise tests of short [Wingate (WANT); Repeated-sprints (RSA)] and long durations [Continuous VO2 test (VCONT); intermittent VO2 test (VINT)] in a cycle-ergometer, until exhaustion. Hematological parameters and IL-6, IL-10 and creatine kinase (CK) levels were determined before (PRE), POST, 30 min, 1, 2, 12 and 24 h after the end of the protocols. Additionally, energy expenditure was determined. Leucocytes, erythrocytes and lymphocytes increased at POST and returned to PRE values at 30 min for all protocols. Lymphocytes had a second decreased at 2 h and granulocytes increased at 2 h when compared to PRE. Both variables returned to PRE values between 12-24 h into recovery. The magnitude of response for IL-6 was greater in VINT and for IL-10 in VCONT. There was no association of energy expenditure within each exercise protocol with the pattern of IL-6, IL-10 and CK responses to the exercise protocols. The present finding support that similar responses after continuous or intermittent acute protocols are observed when exercises are performed to volitional failure, regardless of the duration and mode of exercise.

Validity and usefulness of the Line Drill test for adolescent basketball players: a Bayesian multilevel analysis.

The study examined the validity of the Line Drill test (LD) in male adolescent basketball players (10-15 years). Sensitiveness of the LD to changes in performance across a training and competition season (4 months) was also considered. Age, maturation, body size and LD were measured (n = 57). Sensitiveness of the LD was examined pre- and post-competitive season in a sub-sample (n = 44). The time at each of the four shuttle sprints of the LD (i.e. four stages) was modelled with Bayesian multilevel models. We observed very large correlation of performance at stage 4 (full LD protocol) with stage 3, but lower correlations with the early LD stages. Players' performance by somatic maturity differed substantially only when considering full LD protocol performance. Substantial improvements in all stages of the protocol were observed across the 4-month competitive season. The LD protocol should be shortened by the last full court shuttle sprint, remaining sensitive to training exposure, and independent of maturity status and body size.

Pubertal development of body size and soccer-specific functional capacities in adolescent players.

Pubertal growth in body size and functional capacities were examined in adolescent soccer players (n = 33). The average age at baseline was 10.9 (9.8-11.8 years). Peak height velocity (PHV) and growth curves for body mass and functional performance (countermovement jump, 15-m sprint, agility and Yo-Yo intermittent recovery test - level 1) were determined with Bayesian multilevel models. Estimates for PHV and age at PHV were 8.1 cm/year (95% credible interval: 4.2-18.5 cm/year) and 12.9 years (95% credible interval: 11.8-15.5 years), respectively. Peak body mass velocity occurred 0.48 year after PHV. Jump performance maximum velocity occurred about 2 years after PHV and peak sprint performance maximum velocity was coincident with PHV. Agility and intermittent endurance run performance showed a quadratic trend of improvement of performance, starting to level off at about 3-4 years after PHV. The modelling procedures were efficient to determine pubertal growth curves aligned for chronological age and age at PHV, considering individual differences in maturation when interpreting the development of performance in youth soccer.

Functional and regulatory conservation of the soybean ER stress-induced DCD/NRP-mediated cell death signaling in plants.

BACKGROUND: The developmental and cell death domain (DCD)-containing asparagine-rich proteins (NRPs) were first identified in soybean (Glycine max) as transducers of a cell death signal derived from prolonged endoplasmic reticulum (ER) stress, osmotic stress, drought or developmentally-programmed leaf senescence via the GmNAC81/GmNAC30/GmVPE signaling module. In spite of the relevance of the DCD/NRP-mediated signaling as a versatile adaptive response to multiple stresses, mechanistic knowledge of the pathway is lacking and the extent to which this pathway may operate in the plant kingdom has not been investigated. RESULTS: Here, we demonstrated that the DCD/NRP-mediated signaling also propagates a stress-induced cell death signal in other plant species with features of a programmed cell death (PCD) response. In silico analysis revealed that several plant genomes harbor conserved sequences of the pathway components, which share functional analogy with their soybean counterparts. We showed that GmNRPs, GmNAC81and VPE orthologs from Arabidopsis, designated as AtNRP-1, AtNRP-2, ANAC036 and gVPE, respectively, induced cell death when transiently expressed in N. benthamiana leaves. In addition, loss of AtNRP1 and AtNRP2 function attenuated ER stress-induced cell death in Arabidopsis, which was in marked contrast with the enhanced cell death phenotype displayed by overexpressing lines as compared to Col-0. Furthermore, atnrp-1 knockout mutants displayed enhanced sensitivity to PEG-induced osmotic stress, a phenotype that could be complemented with ectopic expression of either GmNRP-A or GmNRP-B. In addition, AtNRPs, ANAC036 and gVPE were induced by osmotic and ER stress to an extent that was modulated by the ER-resident molecular chaperone binding protein (BiP) similarly as in soybean. Finally, as putative downstream components of the NRP-mediated cell death signaling, the stress induction of AtNRP2, ANAC036 and gVPE was dependent on the AtNRP1 function. BiP overexpression also conferred tolerance to water stress in Arabidopsis, most likely due to modulation of the drought-induced NRP-mediated cell death response. CONCLUSION: Our results indicated that the NRP-mediated cell death signaling operates in the plant kingdom with conserved regulatory mechanisms and hence may be target for engineering stress tolerance and adaptation in crops.

GmNAC30 and GmNAC81 integrate the endoplasmic reticulum stress- and osmotic stress-induced cell death responses through a vacuolar processing enzyme.

Prolonged endoplasmic reticulum and osmotic stress synergistically activate the stress-induced N-rich protein-mediated signaling that transduces a cell death signal by inducing GmNAC81 (GmNAC6) in soybean. To identify novel regulators of the stress-induced programmed cell death (PCD) response, we screened a two-hybrid library for partners of GmNAC81. We discovered another member of the NAC (NAM-ATAF1,2-CUC2) family, GmNAC30, which binds to GmNAC81 in the nucleus of plant cells to coordinately regulate common target promoters that harbor the core cis-regulatory element TGTG[TGC]. We found that GmNAC81 and GmNAC30 can function either as transcriptional repressors or activators and cooperate to enhance the transcriptional regulation of common target promoters, suggesting that heterodimerization may be required for the full regulation of gene expression. Accordingly, GmNAC81 and GmNAC30 display overlapping expression profiles in response to multiple environmental and developmental stimuli. Consistent with a role in PCD, GmNAC81 and GmNAC30 bind in vivo to and transactivate hydrolytic enzyme promoters in soybean protoplasts. A GmNAC81/GmNAC30 binding site is located in the promoter of the caspase-1-like vacuolar processing enzyme (VPE) gene, which is involved in PCD in plants. We demonstrated that the expression of GmNAC81 and GmNAC30 fully transactivates the VPE gene in soybean protoplasts and that this transactivation was associated with an increase in caspase-1-like activity. Collectively, our results indicate that the stress-induced GmNAC30 cooperates with GmNAC81 to activate PCD through the induction of the cell death executioner VPE.