Cytomolecular diversity among Vigna Savi (Leguminosae) subgenera.

The genus Vigna (Leguminosae) comprises about 150 species grouped into five subgenera. The present study aimed to improve the understanding of karyotype diversity and evolution in Vigna, using new and previously published data through different cytogenetic and DNA content approaches. In the Vigna subgenera, we observed a random distribution of rDNA patterns. The 35S rDNA varied in position, from terminal to proximal, and in number, ranging from one (V. aconitifolia, V. subg. Ceratotropis) to seven pairs (V. unguiculata subsp. unguiculata, V. subg. Vigna). On the other hand, the number of 5S rDNA was conserved (one or two pairs), except for V. radiata (V. subg. Ceratotropis), which had three pairs. Genome size was relatively conserved within the genus, ranging from 1C = 0.43 to 0.70 pg in V. oblongifolia and V. unguiculata subsp. unguiculata, respectively, both belonging to V. subg. Vigna. However, we observed a positive correlation between DNA content and the number of 35S rDNA sites. In addition, data from chromosome-specific BAC-FISH suggest that the ancestral 35S rDNA locus is conserved on chromosome 6 within Vigna. Considering the rapid diversification in the number and position of rDNA sites, such conservation is surprising and suggests that additional sites may have spread out from this ancestral locus.

From forest to savanna and back to forest: Evolutionary history of the genus Dimorphandra (Fabaceae).

The tree genus Dimorphandra (Fabaceae), which contains 26 species divided into three subgenera, was studied using DNA sequence data from six chloroplast genome regions (cpDNA) and the nuclear internal transcribed spacer (ITS). The analyses, which included Bayesian phylogenies and haplotype networks, ancestral area reconstructions, and ecological niche modeling, allowed for exploring the evolutionary history of Dimorphandra. Within the subgenus Phaneropsia, the cpDNA sequence data were more closely-related to species from the genus Mora, while the ITS sequence data displayed a closer phylogenetic relationship with the subgenus Pocillum. This incongruence may be due to incomplete lineage sorting associated with ancient polymorphisms. The Amazonian Dimophandra lineages were highly polymorphic and divergent, while those from the Cerrado and the Atlantic Forest had low levels of polymorphisms. The Amazon likely gave rise to the Dimophandra lineage that produced the Cerrado species, while a Cerrado lineage likely gave rise to the Atlantic Forest species. Habitat shifts were identified as a key factor in shaping the late evolutionary history of Dimorphandra.

Cytomolecular trends in Chamaecrista Moench (Caesalpinioideae, Leguminosae) diversification.

Chamaecrista is a Pantropical legume genus of the tribe Cassieae, which includes six other genera. In contrast to most of the other Cassieae genera, Chamaecrista shows significant variability in chromosome number (from 2n = 14 to 2n = 56), with small and morphologically similar chromosomes. Here, we performed a new cytomolecular analysis on chromosome number, genome size, and rDNA site distribution in a molecular phylogenetic perspective to interpret the karyotype trends of Chamaecrista and other two genera of Cassieae, seeking to understand their systematics and evolution. Our phylogenetic analysis revealed that Chamaecrista is monophyletic and can be divided into four major clades corresponding to the four sections of the genus. Chromosome numbers ranged from 2n = 14, 16 (section Chamaecrista) to 2n = 28 (sections Absus, Apoucouita, and Baseophyllum). The number of 5S and 35S rDNA sites varied between one and three pairs per karyotype, distributed on different chromosomes or in synteny, with no obvious phylogenetic significance. Our data allowed us to propose x = 7 as the basic chromosome number of Cassieae, which was changed by polyploidy generating x = 14 (sections Absus, Apoucouita, and Baseophyllum) and by ascending dysploidy to x = 8 (section Chamaecrista). The DNA content values supported this hypothesis, with the genomes of the putative tetraploids being larger than those of the putative diploids. We hypothesized that ascending dysploidy, polyploidy, and rDNA amplification/deamplification are the major events in the karyotypic diversification of Chamaecrista. The chromosomal marks characterized here may have cytotaxonomic potential in future studies.

Comparative floral development in Mimosa (Fabaceae: Caesalpinioideae) brings new insights into merism lability in the mimosoid clade.

The genus Mimosa L. (Leguminosae; Caesalpinioideae; mimosoid clade), comprising more than 500 species, is an intriguing genus because, like other members of the mimosoid clade, it presents an enormous variation in floral characteristics and high merism lability. Thus, this study aimed to elucidate the floral development and identify which ontogenetic pathways give rise to merism variation and andromonoecy in Mimosa caesalpiniifolia, M. pudica, M. bimucronata, and M. candollei. Floral buds at various stages of development and flowers were collected, fixed, and processed for surface analysis (SEM). The development of the buds is synchronous in the inflorescences. Sepals appear simultaneously as individualized primordia in M. caesalpiniifolia and in reversed unidirectional order in M. bimucronata, with union and formation of an early ring-like calyx. Petal primordia appear in unidirectional order, with a noticeably elliptical shape in M. caesalpiniifolia. The wide merism variation in Mimosa results from the absence of organs from inception in the perianth and androecium whorls: in dimerous, trimerous, or tetramerous flowers, the additional organs primordia to compose the expected pentamerous flowers are not initiated. The haplostemonous androecium of M. pudica results from the absence of antepetalous stamens from inception. In the case of intraspecific variations (instabilities), there is no initiation and subsequent abortion of organs in the events of reduction in merosity. In addition, extra primordia are initiated in supernumerary cases. On the other hand, staminate flowers originate from the abortion of the carpel. Mimosa proved to be an excellent model for studying merism variation. The lability is associated with actinomorphic and rather congested flowers in the inflorescences. Our data, in association with others of previous studies, suggest that the high lability in merism appeared in clades that diverged later in the mimosoid clade. Thus, phylogenetic reconstruction studies are needed for more robust evolutionary inferences. The present investigation of ontogenetic processes was relevant to expand our understanding of floral evolution in the genus Mimosa and shed light on the unstable merism in the mimosoid clade.

The Stilbene Synthase Family in Arachis: A Genome-Wide Study and Functional Characterization in Response to Stress.

Peanut (Arachis hypogaea) and its wild relatives are among the few species that naturally synthesize resveratrol, a well-known stilbenoid phytoalexin that plays a crucial role in plant defense against biotic and abiotic stresses. Resveratrol has received considerable attention due to its health benefits, such as preventing and treating various human diseases and disorders. Chalcone (CHS) and Stilbene (STS) Synthases are plant-specific type III Polyketide Synthases (PKSs) that share the same substrates and are key branch enzymes in the biosynthesis of flavonoids and stilbenoids, respectively. Although resveratrol accumulation in response to external stimulus has been described in peanut, there are no comprehensive studies of the CHS and STS gene families in the genus Arachis. In the present study, we identified and characterized 6 CHS and 46 STS genes in the tetraploid peanut and an average of 4 CHS and 22 STS genes in three diploid wild species (Arachis duranensis, Arachis ipaënsis and Arachis stenosperma). The CHS and STS gene and protein structures, chromosomal distributions, phylogenetic relationships, conserved amino acid domains, and cis-acting elements in the promoter regions were described for all Arachis species studied. Based on gene expression patterns of wild A. stenosperma STS genes in response to different biotic and abiotic stresses, we selected the candidate AsSTS4 gene, which is strongly induced by ultraviolet (UV) light exposure, for further functional investigation. The AsSTS4 overexpression in peanut hairy roots significantly reduced (47%) root-knot nematode infection, confirming that stilbene synthesis activation in transgenic plants can increase resistance to pathogens. These findings contribute to understanding the role of resveratrol in stress responses in Arachis species and provide the basis for genetic engineering for improved production of valuable secondary metabolites in plants.

Assembly, annotation and analysis of the chloroplast genome of the Algarrobo tree Neltuma pallida (subfamily: Caesalpinioideae).

BACKGROUND: Neltuma pallida is a tree that grows in arid soils in northwestern Peru. As a predominant species of the Equatorial Dry Forest ecoregion, it holds significant economic and ecological value for both people and environment. Despite this, the species is severely threatened and there is a lack of genetic and genomic research, hindering the proposal of evidence-based conservation strategies. RESULTS: In this work, we conducted the assembly, annotation, analysis and comparison of the chloroplast genome of a N. pallida specimen with those of related species. The assembled chloroplast genome has a length of 162,381 bp with a typical quadripartite structure (LSC-IRA-SSC-IRB). The calculated GC content was 35.97%. However, this is variable between regions, with a higher GC content observed in the IRs. A total of 132 genes were annotated, of which 19 were duplicates and 22 contained at least one intron in their sequence. A substantial number of repetitive sequences of different types were identified in the assembled genome, predominantly tandem repeats (> 300). In particular, 142 microsatellites (SSR) markers were identified. The phylogenetic reconstruction showed that N. pallida grouped with the other Neltuma species and with Prosopis cineraria. The analysis of sequence divergence between the chloroplast genome sequences of N. pallida, N. juliflora, P. farcta and Strombocarpa tamarugo revealed a high degree of similarity. CONCLUSIONS: The N. pallida chloroplast genome was found to be similar to those of closely related species. With a size of 162,831 bp, it had the classical chloroplast quadripartite structure and GC content of 35.97%. Most of the 132 identified genes were protein-coding genes. Additionally, over 800 repetitive sequences were identified, including 142 SSR markers. In the phylogenetic analysis, N. pallida grouped with other Neltuma spp. and P. cineraria. Furthermore, N. pallida chloroplast was highly conserved when compared with genomes of closely related species. These findings can be of great potential for further diversity studies and genetic improvement of N. pallida.

Discovering the genetic modules controlling root nodule symbiosis under abiotic stresses: salinity as a case study.

Legumes form a symbiotic association with rhizobia and fix atmospheric nitrogen in specialized root organs known as nodules. It is well known that salt stress inhibits root nodule symbiosis by decreasing rhizobial growth, rhizobial infection, nodule number, and nitrogenase activity in diverse legumes. Despite this knowledge, the genetic and molecular mechanisms governing salt stress's inhibition of nodulation and nitrogen fixation are still elusive. In this Viewpoint, we summarize the most recent knowledge of the genetic mechanisms that shape this symbiosis according to the salt levels in the soil. We emphasize the relevance of modulating the activity of the transcription factor Nodule Inception to properly shape the symbiosis with rhizobia accordingly. We also highlight the knowledge gaps that are critical for gaining a deeper understanding of the molecular mechanisms underlying the adaptation of the root nodule symbiosis to salt-stress conditions. We consider that filling these gaps can help to improve legume nodulation and harness its ecological benefits even under salt-stress conditions.

Diversity and Efficiency of Rhizobia from a Revegetated Area and Hotspot-Phytophysiognomies Affected by Iron Mining as Indicators of Rehabilitation and Biotechnological Potential.

This study aimed to evaluate the resilience of phytophysiognomies under influence of iron mining by assessing the occurrence, diversity, and symbiotic efficiency of native communities of nitrogen-fixing bacteria that nodulate leguminous plants (rhizobia) in soils of an area revegetated with grass after iron mining activities and in the phytophysiognomies in adjacent areas (Canga, Atlantic Forest, Cerrado, and Eucalyptus-planted forest). Experiments for capturing rhizobia through two species of promiscuous plants, siratro (Macroptilium atropurpureum) and cowpea (Vigna unguiculata), were conducted in a greenhouse. The rhizobial strains isolated were characterized phenotypically, genetically (16S rRNA sequencing and BOX-PCR fingerprinting), and regard symbiotic efficiency of biological nitrogen fixation (BNF) compared to mineral nitrogen and reference strains. Cowpea captured a higher density of rhizobia than siratro did. However, most of the strains captured by siratro had greater symbiotic efficiency. The revegetated area proved to be the community most efficient in N2 fixation and was also the most diverse, whereas Canga was the least diverse. For the two trap species, the predominant genus captured in the revegetated area and in the phytophysiognomies was Bradyrhizobium. The greater symbiotic efficiency and the high genetic diversity of the rhizobial community in the revegetated area indicate the effectiveness of the soil rehabilitation process. The revegetated area and the phytophysiognomies proved to harbor strains with high biotechnological potential. Results indicate that the high functional redundancy of this group of bacteria contributes to the resilience of these phytophysiognomies and the revegetated area.

Dehydration response in Stylosanthes scabra: Transcriptional, biochemical, and physiological modulations.

Stylosanthes scabra, popularly known as stylo, is native to the Brazilian Caatinga semiarid region and stands out as a drought-tolerant shrub forage crop. This work provides information about the plant response during the first 48 h of water deficit, followed by a rehydration treatment. Besides root transcriptomics data, 13 physiological or biochemical parameters were scrutinized. Additionally, RNA-Seq annotated transcripts not associated with the "Viridiplantae" clade were taxonomically categorized. It was found that S. scabra quickly perceives and recovers from the oscillations of the imposed water regime. Physiologically, mechanisms that minimize evapotranspiration or protect the photosynthetic apparatus stood out. Biochemically, it was found that the root tissue invests in synthesizing compounds that can act as osmolytes (proline and sugars), emphasizing the importance of osmoregulation to water deficit acclimation. Consistently, transcriptome and qPCR analyses showed that a set of enriched biological processes with upregulated (UR) transcripts were involved in protective functions against reactive oxygen species or encoding enzymes of important metabolic pathways, which might contribute to S. scabra response to water deficit. Additionally, several UR kinases and transcription factors were identified. Finally, in an innovative approach, some naturally occurring microbial groups (such as Schizosaccharomyces, Bradyrhizobium, etc.) were identified in the S. scabra roots. This study reveals insights into the physiological, biochemical, and molecular mechanisms underlying the S. scabra response to water deficit and provides candidate genes that may be useful in developing drought-tolerant crop varieties through biotechnological applications.

Comparative repeatome analysis reveals new evidence on genome evolution in wild diploid Arachis (Fabaceae) species.

MAIN CONCLUSION: Opposing changes in the abundance of satellite DNA and long terminal repeat (LTR) retroelements are the main contributors to the variation in genome size and heterochromatin amount in Arachis diploids. The South American genus Arachis (Fabaceae) comprises 83 species organized in nine taxonomic sections. Among them, section Arachis is characterized by species with a wide genome and karyotype diversity. Such diversity is determined mainly by the amount and composition of repetitive DNA. Here we performed computational analysis on low coverage genome sequencing to infer the dynamics of changes in major repeat families that led to the differentiation of genomes in diploid species (x = 10) of genus Arachis, focusing on section Arachis. Estimated repeat content ranged from 62.50 to 71.68% of the genomes. Species with different genome composition tended to have different landscapes of repeated sequences. Athila family retrotransposons were the most abundant and variable lineage among Arachis repeatomes, with peaks of transpositional activity inferred at different times in the evolution of the species. Satellite DNAs (satDNAs) were less abundant, but differentially represented among species. High rates of evolution of an AT-rich superfamily of satDNAs led to the differential accumulation of heterochromatin in Arachis genomes. The relationship between genome size variation and the repetitive content is complex. However, largest genomes presented a higher accumulation of LTR elements and lower contents of satDNAs. In contrast, species with lowest genome sizes tended to accumulate satDNAs in detriment of LTR elements. Phylogenetic analysis based on repetitive DNA supported the genome arrangement of section Arachis. Altogether, our results provide the most comprehensive picture on the repeatome dynamics that led to the genome differentiation of Arachis species.

The innovation of the symbiosome has enhanced the evolutionary stability of nitrogen fixation in legumes.

Nitrogen-fixing symbiosis is globally important in ecosystem functioning and agriculture, yet the evolutionary history of nodulation remains the focus of considerable debate. Recent evidence suggesting a single origin of nodulation followed by massive parallel evolutionary losses raises questions about why a few lineages in the N2 -fixing clade retained nodulation and diversified as stable nodulators, while most did not. Within legumes, nodulation is restricted to the two most diverse subfamilies, Papilionoideae and Caesalpinioideae, which show stable retention of nodulation across their core clades. We characterize two nodule anatomy types across 128 species in 56 of the 152 genera of the legume subfamily Caesalpinioideae: fixation thread nodules (FTs), where nitrogen-fixing bacteroids are retained within the apoplast in modified infection threads, and symbiosomes, where rhizobia are symplastically internalized in the host cell cytoplasm within membrane-bound symbiosomes (SYMs). Using a robust phylogenomic tree based on 997 genes from 147 Caesalpinioideae genera, we show that losses of nodulation are more prevalent in lineages with FTs than those with SYMs. We propose that evolution of the symbiosome allows for a more intimate and enduring symbiosis through tighter compartmentalization of their rhizobial microsymbionts, resulting in greater evolutionary stability of nodulation across this species-rich pantropical legume clade.

Optimal economical dose of nitrogen and diagnostic leaf to assess the nutritional status of cowpea / Dose ótima econômica de nitrogênio e folha diagnóstica para avaliação do estado nutricional do feijão-caupi

Considering that crop nutrition is essential to obtain high yields, the objective of this study was to determine the optimal economicaldose of nitrogen (N) associated with maximum technical and economical yield. Additionally, to correlate cowpea cultivars with N contents and yield. The experimentwas conducted under the edaphoclimatic conditions of Teresina, PI, Brazil, in Entisol (Fluvic Neosol), in the second half of 2017, in a randomized block design in a factorial scheme (2x2x5), whose factors were: (i) cowpea genotypes (BRS Imponente and BRS Itaim), (ii) form of application of N fertilization (basal + top-dressing or fully top-dressing) and (iii) N doses (zero, 10, 30, 50 and 70 kg ha-1-urea as source). The variables measured were the total N content in the plant tissue, with a collection ofleaves +1 and +3, and grain yield. When analyzing the effect of the interaction, there was significance only for the factors form of application and N doses. However, when the doses were further analyzed for each form of N fertilization, the best responsemodel was the quadratic, whose point of maximum physical yield was verified with N doses of 34 and 44 kg ha-1for basal + top-dressing and fully top-dressing applications, respectively. Furthermore, the most economical doses for basal + top-dressing and fully top-dressing N applications were 26.0 and 35.6 kg ha-1, respectively. For N, the leaf that best represents the nutritional status for leaf diagnosis was +3.(AU)

Considerando que a nutrição da cultura é preponderante para obtenção de elevadas produtividades, objetivou-se determinar a dose ótima econômica de N associada à máxima produtividade técnica e econômica. Adicionalmente, realizar correlações entre cultivares de feijão-caupi com os teores de N e a produtividade. O experimento foi conduzido nas condições edafoclimáticas de Teresina, PI, em um Neossolo Flúvico, no segundo semestre de 2017, em delineamento em blocos casualizados em esquema fatorial (2x2x5), cujos fatores foram: (i) genótiposde feijão-caupi (BRS Imponente e BRS Itaim), (ii) época de aplicação da adubação nitrogenada (fundação+cobertura ou totalmente em cobertura) e (iii) doses de N (zero, 10, 30, 50 e 70 kg ha-1­fonte ureia). As variáveis mensuradas foram a análise do N total do tecido vegetal com a coleta da folha +1 e +3, além da produtividade de grãos. Quando analisamos o efeito da interação houve significância somente para os fatores época de aplicação e doses de N, e quando desdobramos as doses para cada época de adubação nitrogenada o melhor modelo de resposta foi o quadrático, cujo ponto de máxima produtividade física foram verificados com as doses de 34 e 44 kg ha-1de N para a aplicação na fundação+cobertura e totalmente em cobertura, respectivamente. Ainda, a doses mais econômica para a aplicação de N em fundação+cobertura e totalmente em cobertura foram de 26,0 e 35,6 kg ha-1, respectivamente. Para o N a folha que melhor representa o estado nutricional para a diagnose foliar mostrou-se ser a +3.(AU)

Low genetic variation of foliar traits among Prosopis chilensis (Leguminosae) provenances.

Prosopis chilensis (Molina) Stuntz (Leguminosae) is a valuable native species in Argentina that has been proposed to be used in reforestation, afforestation and restoration programmes. Natural provenances show important differentiation in height, shape, spine size, fruits and foliar traits throughout their distribution in the semiarid Monte ecoregion. The goal of this work was to characterize the genetic basis of the leaf variation in P. chilensis aiming to contribute to the improvement management program. We analyzed morphological variation and estimate narrow sense heritability for ten quantitative traits from a provenance-progeny trial founded from open pollinated families. We assessed the variance components by a generalized linear mixed model. Differences among provenances were quantified through univariate QST statistics and multivariate discriminant analysis of principal components. Finally, univariate and multivariate neutrality test were conducted to unveil the evolutionary forces that shape the variation. Univariate and multivariate analysis showed low genetic variation in foliar traits among provenances grown in the common garden. Consistently, the QST estimates for each trait were low. Both, the univariate (QST-FST comparison) and the multivariate neutrality test suggest that the leaf variation among provenances may be shaped by genetic drift rather than selective forces. Heritability estimates were significant only for leaflet apex and leaflet apex/leaflet area. Since genetic variation for most foliar traits among provenances estimated under controlled environmental conditions were very low or absent, the variation described in the wild would be explained merely by plastic response to varying environments. These results are discussed in terms of adaptive strategies and the use of different provenances as seed sources within the framework of the improvement program. It is expected that P. chilensis seeds or seedlings from trees selected under economical criteria will be able to develop in different areas thanks to the phenotypic plasticity of leaf traits.

Higher frequency of legitimate pollinators and fruit set of autotetraploid trees of Libidibia ferrea (Leguminosae) compared to diploids in a mixed tropical urban population.

In mixed-ploidy populations, newly formed polyploids initially occur at low frequencies when compared to diploids. However, polyploidy may lead to morphological and phenological changes, which promote reproductive isolation and favor polyploid establishment and reproductive success. Additionally, previous studies have shown that polyploidy can confer some adaptive advantages to organisms in stressful environments. Here, we investigate variation in reproductive phenology, floral traits and reproductive success between diploid and autotetraploid trees of Libidibia ferrea (Mart. Ex Tul.) L.P. Queiroz (Leguminosae) in a mixed tropical urban population, a stressful environment. We assessed ploidy levels, flowering and fruiting phenology, flowering synchrony, floral and reproductive biology, pollination and fruit and seed set. We tested the hypothesis that autotetraploid individuals have a higher frequency of pollinators and higher fruit and seed set per inflorescence (as a proxy of reproductive success) than diploids in an urban green space. Libidibia ferrea is a good model to test our hypothesis because it is self-incompatible (i.e. relies on pollinators to set fruits). In the urban ecosystem studied, we found that diploids flowered for 6-7 months/year and autotetraploids for 3-5 months/year. Flowering synchrony was low between and within cytotypes and even though autotetraploids and diploids exhibited some overlap in flowering period, diploids flowered alone for 2-3 months. Autotetraploids had significantly more flowers per inflorescences, larger flowers and larger pollen grains (as expected for polyploids), but also a higher frequency of visits by legitimate pollinators including two exclusive ones, and higher fruit and seed set per inflorescence when compared to diploids, despite having a shorter flowering period. Our findings reveal some advantages for polyploids over their related diploids in a tropical urban green space. Also, our results highlight the need for more studies that seek to understand abiotic mechanisms affecting reproductive output of polyploids in urban ecosystems.

Integration of metabolomics and transcriptomics data to further characterize Gliricidia sepium (Jacq.) Kunth under high salinity stress.

Soil salinity is one abiotic stress that threatens agriculture in more than 100 countries. Gliricidia [Gliricidia sepium (Jacq.) Kunth] is a multipurpose tree known for its ability to adapt to a wide range of soils; however, its tolerance limits and responses to salt stress are not yet well understood. In this study, after characterizing the morphophysiological responses of young gliricidia plants to salinity stress, leaf metabolic and transcription profiles were generated and submitted to single and integrated analyses. RNA from leaf samples were subjected to RNA sequencing using an Illumina HiSeq platform and the paired-end strategy. Polar and lipidic fractions from leaf samples were extracted and analyzed on an ultra-high-performance liquid chromatography (UHPLC) coupled with electrospray ionization quadrupole time-of-flight high-resolution mass spectrometry (MS) system. Acquired data were analyzed using the OmicsBox, XCMS Online, MetaboAnalyst, and Omics Fusion platforms. The substrate salinization protocol used allowed the identification of two distinct responses to salt stress: tolerance and adaptation. Single analysis on transcriptome and metabolome data sets led to a group of 5,672 transcripts and 107 metabolites differentially expressed in gliricidia leaves under salt stress. The phenylpropanoid biosynthesis was the most affected pathway, with 15 metabolites and three genes differentially expressed. Results showed that the differentially expressed metabolites and genes from this pathway affect mainly short-term salt stress (STS). The single analysis of the transcriptome identified 12 genes coding for proteins that might play a role in gliricidia response at both STS and long-term salt stress (LTS). Further studies are needed to reveal the mechanisms behind the adaptation response.

Origin and Evolutionary Dynamics of the miR2119 and ADH1 Regulatory Module in Legumes.

MicroRNAs are important regulators of gene expression in eukaryotes. Previously, we reported that in Phaseolus vulgaris, the precursor for miR2119 is located in the same gene as miR398a, conceiving a dicistronic MIR gene. Both miRNA precursors are transcribed and processed from a single transcript resulting in two mature microRNAs that regulate the mRNAs encoding ALCOHOL DEHYDROGENASE 1 (ADH1) and COPPER-ZINC SUPEROXIDE DISMUTASE 1 (CSD1). Genes for miR398 are distributed throughout the spermatophytes; however, miR2119 is only found in Leguminosae species, indicating its recent emergence. Here, we used public databases to explore the presence of the miR2119 sequence in several plant species. We found that miR2119 is present only in specific clades within the Papilionoideae subfamily, including important crops used for human consumption and forage. Within this subfamily, MIR2119 and MIR398a are found together as a single gene in the genomes of the Millettioids and Hologalegina. In contrast, in the Dalbergioids MIR2119 is located in a different locus from MIR398a, suggesting this as the ancestral genomic organization. To our knowledge, this is a unique example where two separate MIRNA genes have merged to generate a single polycistronic gene. Phylogenetic analysis of ADH1 gene sequences in the Papilionoideae subfamily revealed duplication events resulting in up to four ADH1 genes in certain species. Notably, the presence of MIR2119 correlates with the conservation of target sites in particular ADH1 genes in each clade. Our results suggest that post-transcriptional regulation of ADH1 genes by miR2119 has contributed to shaping the expansion and divergence of this gene family in the Papilionoideae. Future experimental work on ADH1 regulation by miR2119 in more legume species will help to further understand the evolutionary history of the ADH1 gene family and the relevance of miRNA regulation in this process.

Genome-Wide Identification of the CrRLK1L Subfamily and Comparative Analysis of Its Role in the Legume-Rhizobia Symbiosis.

The plant receptor-like-kinase subfamily CrRLK1L has been widely studied, and CrRLK1Ls have been described as crucial regulators in many processes in Arabidopsis thaliana (L.), Heynh. Little is known, however, about the functions of these proteins in other plant species, including potential roles in symbiotic nodulation. We performed a phylogenetic analysis of CrRLK1L subfamily receptors of 57 different plant species and identified 1050 CrRLK1L proteins, clustered into 11 clades. This analysis revealed that the CrRLK1L subfamily probably arose in plants during the transition from chlorophytes to embryophytes and has undergone several duplication events during its evolution. Among the CrRLK1Ls of legumes and A. thaliana, protein structure, gene structure, and expression patterns were highly conserved. Some legume CrRLK1L genes were active in nodules. A detailed analysis of eight nodule-expressed genes in Phaseolus vulgaris L. showed that these genes were differentially expressed in roots at different stages of the symbiotic process. These data suggest that CrRLK1Ls are both conserved and underwent diversification in a wide group of plants, and shed light on the roles of these genes in legume-rhizobia symbiosis.

Acúmulo e partição de biomassa e macronutrientes de cultivares de feijão-vagem em cultivo protegido fertirrigado / Accumulation and partitioning of biomass and macronutrients of bush snap bean genotypes in semi-hydroponic system

Para um melhor manejo da fertirrigação em cultivos protegidos de olerícolas, como o feijão-vagem, faz-se necessário conhecer a demanda nutricional dessas plantas. Portanto, objetivou-se caracterizar o acúmulo de biomassa e nutrientes por genótipos de feijão-vagem em cultivo protegido fertirrigado. Para tanto, foi conduzido experimento inteiramente casualizado em casa-de-vegetação, com os genótipos UEL-1 e Alessa, cultivados em vasos plásticos com substrato areia grossa e fertirrigação por micro-aspersão. A cada dez dias, as plantas foram coletadas e mensuradas a massa de matéria seca e a concentração nos tecidos de nitrogênio (N), fósforo (P), potássio (K), cálcio (Ca), magnésio (Mg) e enxofre (S), ajustando-se o acúmulo destes ao longo do tempo por meio do modelo gaussiano. A produtividade de vagens frescas (kg m-2) também foi medida. O acúmulo de biomassa e nutrientes foi intensificado a partir dos 20 dias após a emergência (DAE), atingindo valores máximos próximo aos 50 DAE. O genótipo Alessa teve maior acúmulo de biomassa e macronutrientes, enquanto UEL-1 foi mais produtivo em vagens frescas, caracterizando maior eficiência no uso dos nutrientes. Para ambos genótipos, o N teve o maior acúmulo, seguido por K, Ca, P, S e Mg.

For a better management of fertigation in protected cultivation of vegetables such as snap beans, it is important to know the nutritional requirements of the plants. Thus, we aimed to characterize the biomass and nutrients accumulation of bush snap beans genotypes. For that, an experiment was carried out in greenhouse, where the genotypes UEL-1 and Alessa were grown in plastic pots with coarse sand as substrate and fertigation by micro sprinklers. Each ten days, plants were sampled and measured the dry matter and the concentrations of elements such as nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S), adjusting their accumulation over time by the gaussian model. The fresh pods yield (kg m-2) was also evaluated. The accumulation of biomass and macronutrients are intensified from 20 days after emergence (DAE), reaching maximum values near 50 DAE. The genotype Alessa presented a higher overall accumulation, while UEL-1 was more productive regarding fresh pods, characterizing such genotype as more efficient for using the macronutrients. For both genotypes, N had the highest accumulation, followed by K, Ca, P, S and Mg.

Acúmulo e partição de biomassa e macronutrientes de cultivares de feijão-vagem em cultivo protegido fertirrigado / Accumulation and partitioning of biomass and macronutrients of bush snap bean genotypes in semi-hydroponic system

Para um melhor manejo da fertirrigação em cultivos protegidos de olerícolas, como o feijão-vagem, faz-se necessário conhecer a demanda nutricional dessas plantas. Portanto, objetivou-se caracterizar o acúmulo de biomassa e nutrientes por genótipos de feijão-vagem em cultivo protegido fertirrigado. Para tanto, foi conduzido experimento inteiramente casualizado em casa-de-vegetação, com os genótipos UEL-1 e Alessa, cultivados em vasos plásticos com substrato areia grossa e fertirrigação por micro-aspersão. A cada dez dias, as plantas foram coletadas e mensuradas a massa de matéria seca e a concentração nos tecidos de nitrogênio (N), fósforo (P), potássio (K), cálcio (Ca), magnésio (Mg) e enxofre (S), ajustando-se o acúmulo destes ao longo do tempo por meio do modelo gaussiano. A produtividade de vagens frescas (kg m-2) também foi medida. O acúmulo de biomassa e nutrientes foi intensificado a partir dos 20 dias após a emergência (DAE), atingindo valores máximos próximo aos 50 DAE. O genótipo Alessa teve maior acúmulo de biomassa e macronutrientes, enquanto UEL-1 foi mais produtivo em vagens frescas, caracterizando maior eficiência no uso dos nutrientes. Para ambos genótipos, o N teve o maior acúmulo, seguido por K, Ca, P, S e Mg.(AU)

For a better management of fertigation in protected cultivation of vegetables such as snap beans, it is important to know the nutritional requirements of the plants. Thus, we aimed to characterize the biomass and nutrients accumulation of bush snap beans genotypes. For that, an experiment was carried out in greenhouse, where the genotypes UEL-1 and Alessa were grown in plastic pots with coarse sand as substrate and fertigation by micro sprinklers. Each ten days, plants were sampled and measured the dry matter and the concentrations of elements such as nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and sulfur (S), adjusting their accumulation over time by the gaussian model. The fresh pods yield (kg m-2) was also evaluated. The accumulation of biomass and macronutrients are intensified from 20 days after emergence (DAE), reaching maximum values near 50 DAE. The genotype Alessa presented a higher overall accumulation, while UEL-1 was more productive regarding fresh pods, characterizing such genotype as more efficient for using the macronutrients. For both genotypes, N had the highest accumulation, followed by K, Ca, P, S and Mg.(AU)

Rational design of mimetic peptides based on the interaction between Inga laurina inhibitor and trypsins for Spodoptera cosmioides pest control.

The interaction of Inga laurina Kunitz inhibitor with insect trypsins is an example of protein-protein interaction with potential application for the pest control. However, the crop field application of proteins as inhibitors is limited due to high production cost, the large molecular size and low environmental stability. The use of mimetic peptides that have molecular features associated with the protein inhibitor can result in a product with lower cost and higher efficiency for the agricultural application. Here, we designed mimetic peptides deriving from globular domains of ILTI that are predicted to interact with trypsin enzymes of Lepidoptera pest. Two linear peptides were identified and synthetized from the interface of interaction between trypsin-ILTI complexes. These peptides were derived due to its high-energy contribution for the biding affinity between the enzyme-protein inhibitor. The peptides showed structural stability, propensity to adopt the bound conformation also without the context of the protein, inhibitory activity of digestive trypsins and toxic effects on the S. cosmioides, indicating that they can be used as potential inhibitor for pest control.