RESUMO
Rhizobial phosphatidylcholine (PC) is thought to be a critical phospholipid for the symbiotic relationship between rhizobia and legume host plants. A PC-deficient mutant of Sinorhizobium meliloti overproduces succinoglycan, is unable to swim, and lacks the ability to form nodules on alfalfa (Medicago sativa) host roots. Suppressor mutants had been obtained which did not overproduce succinoglycan and regained the ability to swim. Previously, we showed that point mutations leading to altered ExoS proteins can reverse the succinoglycan and swimming phenotypes of a PC-deficient mutant. Here, we report that other point mutations leading to altered ExoS, ChvI, FabA, or RpoH1 proteins also revert the succinoglycan and swimming phenotypes of PC-deficient mutants. Notably, the suppressor mutants also restore the ability to form nodule organs on alfalfa roots. However, nodules generated by these suppressor mutants express only low levels of an early nodulin, do not induce leghemoglobin transcript accumulation, thus remain white, and are unable to fix nitrogen. Among these suppressor mutants, we detected a reduced function mutant of the 3-hydoxydecanoyl-acyl carrier protein dehydratase FabA that produces reduced amounts of unsaturated and increased amounts of shorter chain fatty acids. This alteration of fatty acid composition probably affects lipid packing thereby partially compensating for the previous loss of PC and contributing to the restoration of membrane homeostasis.
Assuntos
Ácidos Graxos , Medicago sativa , Fosfatidilcolinas , Nodulação , Sinorhizobium meliloti , Simbiose , Sinorhizobium meliloti/fisiologia , Sinorhizobium meliloti/genética , Medicago sativa/microbiologia , Medicago sativa/genética , Nodulação/genética , Ácidos Graxos/metabolismo , Ácidos Graxos/biossíntese , Fosfatidilcolinas/metabolismo , Fosfatidilcolinas/biossíntese , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Nódulos Radiculares de Plantas/microbiologia , Nódulos Radiculares de Plantas/genética , Nódulos Radiculares de Plantas/metabolismo , Mutação , Polissacarídeos Bacterianos/metabolismo , Polissacarídeos Bacterianos/biossíntese , Fixação de NitrogênioRESUMO
Breeding for dry matter yield and persistence in alfalfa (Medicago sativa L.) can take several years as these traits must be evaluated under multiple harvests. Therefore, genotype-by-harvest interaction should be incorporated into genomic prediction models to explore genotypes' adaptability and stability. In this study, we investigated how enviromics could help to predict the genotypic performance under multiharvest alfalfa breeding trials by evaluating 177 families across 11 harvests under four cross-validation scenarios. All scenarios were analyzed using six models in a Bayesian mixed model framework. Our results demonstrate that models accounting to the enviromics information led to an increase of genetic variance and a decrease in the error variance, indicating better biological explanation when the enviromic information was incorporated. Furthermore, models that accounted for enviromic data led to higher predictive ability (PA) in a reduced number of harvests used in the training data set. The best enviromic models (M2 and M3) outperformed the base model (GBLUP model-M0) for predicting adaptability and persistence across all cross-validation scenarios. Incorporating environmental covariates also provided higher PA for persistence compared with the base model, as predictions increased from 0 to 0.16, 0.20, 0.56, and 0.46 for CV00, CV1, CV0, and CV2. The results also demonstrate that GBLUP without enviromics term has low power to predict persistence, thus the adoption of enviromics is a cheap and efficient alternative to increase accuracy and biological meaning.
Assuntos
Medicago sativa , Herança Multifatorial , Medicago sativa/genética , Teorema de Bayes , Genoma de Planta , Modelos Genéticos , Melhoramento Vegetal , Genômica/métodosRESUMO
KEY MESSAGE: T-DNA and CRISPR/Cas9-mediated knockout of polyester synthase-like genes delays flowering time in Arabidopsis thaliana and Medicago sativa (alfalfa). Thus, we here present the first report of edited alfalfa with delayed flowering.
Assuntos
Arabidopsis , Medicago sativa , Medicago sativa/genética , Sistemas CRISPR-Cas/genética , Flores/genética , Arabidopsis/genéticaRESUMO
KEYMESSAGE: We present the first report on base editing in alfalfa. Specifically, we showed edited alfalfa with tolerance to both sulfonylurea- and imidazolinone-type herbicides.
Assuntos
Edição de Genes/métodos , Herbicidas/farmacologia , Medicago sativa/efeitos dos fármacos , Medicago sativa/genética , Resistência a Herbicidas/genética , Herbicidas/química , Plantas Geneticamente Modificadas , Compostos de Sulfonilureia/farmacologiaRESUMO
Mycobacterium avium subsp. paratuberculosis (MAP) is the etiological agent of Paratuberculosis, a contagious, untreatable, and chronic granulomatous enteritis that results in diarrhea, emaciation, and death in farmed ruminants (i.e., cattle, sheep, and goats). In this study, the Ag85B antigen from MAP was expressed in transgenic alfalfa as an attractive vaccine candidate. Agrobacterium-mediated transformation allowed the rescue of 56 putative transformed plants and transgenesis was confirmed in 19 lines by detection of the Ag85B gene (MAP1609c) by PCR. Line number 20 showed the highest Ag85B expression [840 ng Ag85B per gram of dry weight leaf tissue, 0.062% Total Soluble Protein (TSP)]. Antigenicity of the plant-made Ag85B was evidenced by its reactivity with a panel of sera from naturally MAP-infected animals, whereas immunogenicity was assessed in mice immunized by either oral or subcutaneous routes. The plant-made Ag85B antigen elicited humoral responses by the oral route when co-administered with cholera toxin as adjuvant; significant levels of anti-85B antibodies were induced in serum (IgG) and feces (IgA). Long-lasting immunity was evidenced at day 180 days post-first oral immunization. The obtained alfalfa lines expressing Ag85B constitute the first model of a plant-based vaccine targeting MAP. The initial immunogenicity assessment conducted in this study opens the path for a detailed characterization of the properties of this vaccine candidate.
Assuntos
Antígenos de Bactérias/imunologia , Imunidade , Medicago sativa/metabolismo , Mycobacterium avium subsp. paratuberculosis/imunologia , Adjuvantes Imunológicos/farmacologia , Administração Oral , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Antígenos de Bactérias/sangue , Imunização , Medicago sativa/genética , Camundongos Endogâmicos BALB C , Plantas Geneticamente ModificadasRESUMO
KEY MESSAGE: A novel genetic tool to bypass transgene silencing in alfalfa.
Assuntos
Inativação Gênica , Vetores Genéticos , Medicago sativa/genética , Glicina/análogos & derivados , Glicina/farmacologia , Medicago sativa/efeitos dos fármacos , Medicago sativa/metabolismo , Plantas Geneticamente Modificadas , Transgenes , GlifosatoRESUMO
Alfalfa (Medicago sativa L.) is one of the most important forage crops worldwide. As a perennial, alfalfa is cut several times each year. Farmers face a dilemma: if cut earlier, forage nutritive value is much higher but regrowth is affected and the longevity of the stand is severely compromised. On the other hand, if alfalfa is cut later at full flower, stands persist longer and more biomass may be harvested, but the nutritive value diminishes. Alfalfa is a strict long-day plant. We reasoned that by manipulating the response to photoperiod, we could delay flowering to improve forage quality and widen each harvesting window, facilitating management. With this aim, we functionally characterized the FLOWERING LOCUS T family of genes, represented by five members: MsFTa1, MsFTa2, MsFTb1, MsFTb2 and MsFTc. The expression of MsFTa1 correlated with photoperiodic flowering and its down-regulation led to severe delayed flowering. Altogether, with late flowering, low expression of MsFTa1 led to changes in plant architecture resulting in increased leaf to stem biomass ratios and forage digestibility. By manipulating photoperiodic flowering, we were able to improve the quality of alfalfa forage and management, which may allow farmers to cut alfalfa of high nutritive value without compromising stand persistence.
Assuntos
Regulação da Expressão Gênica de Plantas , Medicago sativa/genética , Valor Nutritivo , Proteínas de Plantas/genética , Biomassa , Regulação para Baixo , Flores/fisiologia , Medicago sativa/química , FotoperíodoRESUMO
This study was carried out to determine the yield and quality characteristics of some alfalfa village populations cultivated by producers in Bingol province of Turkey. Alfalfa seeds were obtained from 23 different locations in 2015. A three replicated, randomised complete block designed field trial was established in 2016 including these genotypes and four registered varieties. As a result of three year trials, it was determined that the populations obtained from the villages of Servi, Mutluca, Garip, Sarçiçek-1 and Bagliisa produced highest green herbage and hay yields. When we compare the quality results, Kumgecit, Küçüktekõren and enkõy-1 populations stands out in terms of crude protein ratio. Highest crude protein yield was obtained from Servi population. In terms of relative feed value, it was observed that the varieties were better qualfied than the populations. It is concluded that the populations of Servi, Mutluca, Garip, Sarçiçek-1 and Bagliisa can be used in breeding studies especially to obtain genetic progress in yield of alfalfa for feed and bioenergy production. For the genetic improvement of current genotypes with higher crude protein ratio, Kumgecit, Küçüktekõren and enkõy-1 populations can be used as a source. This study showed that, East Anatolia region is not just live-conserving highly diversified species but also covering special intra-species genetic diversity in microclimatic zones of Turkey to be used to improve the global forage and bioenergy cropproduction.(AU)
Este estudo foi realizado para determinar as características de rendimento e qualidade de algumas populações de alfafa cultivadas por produtores na província de Bingol, na Turquia. As sementes de alfafa foram obtidas de 23 locais diferentes em 2015. Em 2016, foi estabelecido um ensaio de campo com três repetições, aleatórias e desenvolvido em bloco, incluindo esses genótipos e quatro variedades registradas. Com o resultado de testes de três anos, determinou-se que as populações obtidas nas aldeias de Servi, Mutluca, Garip, Sarçiçek-1 e Bagliisa produziam maiores colheitas de forragem verde e feno. Quando comparamos os resultados de qualidade, as populações Kumgecit, Küçüktekõren e enkõy-1 se destacam em termos de proporção de proteína bruta. O maior rendimento de proteína bruta foi obtido da população de Servi. Em termos de valor relativo de ração, observou-se que as variedades eram mais qualificadas do que as populações. Conclui-se que as populações de Servi, Mutluca, Garip, Sarçiçek-1 e Bagliisa podem ser utilizadas em estudos de melhoramento, especialmente para obter progresso genético no rendimento de alfafa para produção de ração e bioenergia. Para o aprimoramento genético dos genótipos atuais com maior proporção de proteína bruta, as populações Kumgecit, Küçüktekõren e enkõy-1 podem ser usadas como fonte. Este estudo mostrou que, a região da Anatólia Oriental não é apenas espécies altamente diversificadas conservadoras de vida, mas também abrange diversidade genética intraespécie especial em zonas microclimáticas da Turquia, a ser usada para melhorar a produção global de forragem e bioenergia.(AU)
Assuntos
Medicago sativa/crescimento & desenvolvimento , Medicago sativa/genética , Agricultura Sustentável , Melhoramento Vegetal , TurquiaRESUMO
This study was conducted to evaluate the fermentative profile and microbial populations of wilted and non-wilted alfalfa silages ensiled with or without inoculant and the population dynamics of lactic acid bacteria (LAB) of wilted alfalfa plant and theirs silage. A 2 × 2 × 6 factorial arrangement was used, with the absence or presence of wilting (W), with and without bacterial inoculant (I) and six fermentation periods (P) (1, 3, 7, 14, 28 and 56 days), in a completely randomized design, with three replicates. The alfalfa was slightly wilted for 6 h and increased the dry matter content from 133.9 to 233.4 g/kg. It was performed the cultivation, followed by the isolation of LAB from samples of alfalfa forage before ensiling and its silage only in non-inoculated silages, after different fermentation periods. DNA was extracted from the isolated strains of LAB; the 16S rRNA gene sequences were amplified by PCR and the sequences were compared to those available from the GenBank database. Wilting provided silages with lower pH, ammonia nitrogen and acetic acid concentrations. The wilting process did not alter the amount of LAB; however, it affected the LAB diversity of the silages. The Lactobacillus plantarum was the predominant species in non-wilted and wilted silages.
Assuntos
Lactobacillales/genética , Medicago sativa/genética , Medicago sativa/microbiologia , Ácido Acético , Amônia , Fermentação , Genética Populacional/métodos , Concentração de Íons de Hidrogênio , Ácido Láctico , Lactobacillus/genética , Lactobacillus plantarum/genética , Nitrogênio , Silagem/microbiologia , Clima TropicalRESUMO
BACKGROUND: Genotyping-by-sequencing (GBS) has been used broadly in genetic studies for several species, especially those with agricultural importance. However, its use is still limited in autopolyploid species because genotype calling software generally fails to properly distinguish heterozygous classes based on allele dosage. RESULTS: VCF2SM is a Python script that integrates sequencing depth information of polymorphisms in variant call format (VCF) files and SUPERMASSA software for quantitative genotype calling. VCFs can be obtained from any variant discovery software that outputs exact allele sequencing depth, such as a modified version of the TASSEL-GBS pipeline provided here. VCF2SM was successfully applied in analyzing GBS data from diverse panels (alfalfa and potato) and full-sib mapping populations (alfalfa and switchgrass) of polyploid species. CONCLUSIONS: We demonstrate that our approach can help plant geneticists working with autopolyploid species to advance their studies by distinguishing allele dosage from GBS data.