Interspecific hybridization and inoculation with Pantoea eucalypti improve forage performance of Lotus crop species under alkaline stress.

This study was designed to elucidate the physiological responses of three Lotus forage accessions to alkaline stress, and the influence of inoculating with Pantoea eucalypti endophyte strain on alkaline stress mitigation. A diploid L. corniculatus (Lc) accession, L. tenuis (Lt), and the interspecific hybrid Lt × Lc obtained from these two parental lines were exposed to alkaline stress (pH 8.2). Both Lt and the Lt × Lc hybrid are alkaline-tolerant compared to Lc, based on observations that dry mass was not reduced under stress, and there were no chlorosis symptoms on leaf blades. In all three Lotus accessions, Fe2+ concentration under stress decreased in aerial parts and simultaneously increased in roots. Inoculation with P. eucalypti considerably increased Fe2+ content in shoots of all three Lotus forage species under alkaline treatment. Photochemical efficiency of PSII was affected in Lc accession only when exposed to alkaline treatment. However, when cultivated under alkalinity with inoculation, plants recovered and had photosynthetic parameters equivalent to those in the control treatment. Together, the results highlight the importance of inoculation with P. eucalypti, which contributes significantly to mitigating alkaline stress. All results provide useful information for improving alkaline tolerance traits of Lotus forage species and their interspecific hybrids.

Hybridization in Canids-A Case Study of Pampas Fox (Lycalopex gymnocercus) and Domestic Dog (Canis lupus familiaris) Hybrid.

Hybridization between species with different evolutionary trajectories can be a powerful threat to wildlife conservation. Anthropogenic activities, such as agriculture and livestock, have led to the degradation and loss of natural habitats for wildlife. Consequently, the incidence of interspecific hybridization between wild and domestic species has increased, although cases involving species of different genera are rare. In Vacaria, a Southern city in Brazil, a female canid with a strange phenotype, which had characteristics between the phenotype of the domestic dog (Canis familiaris) and that of the pampas fox (Lycalopex gymnocercus), was found. Our analysis suggests that the animal is a hybrid between a domestic dog and a pampas fox, but future studies are necessary to investigate additional cases of this hybridization in nature. This finding worries for the conservation of wild canids in South America, especially concerning Lycalopex species. Hybridization with the domestic dog may have harmful effects on pampas fox populations due to the potential for introgression and disease transmission by the domestic dog. Therefore, future studies to explore the consequences of hybridization on genetics, ecology, and behavior of wild populations will be essential to improve the conservation of this species.

Use of Molecular Genetic Methods to Reduce the Risk of Incorrect Identification of Fish Strains in Brazilian Aquaculture.

The identification of fish species using traditional methods is generally based only on morphological characteristics and these methods are currently under review. This kind of identification of hybrid fishes solely based on their morphologies may be unreliable, especially when the samples include juveniles and post-F1 lineage fishes. Therefore, in the present study, we used molecular markers to accurately identify the fish species of economic interest that are used as materials in the projects developed in research institutions. We evaluated six lots of fishes sampled from different research centers, containing a total of 84 specimens acquired from private fish farms that were considered to be the representatives of pure species. Genetic analyses of all the specimens revealed that, globally, 22 samples (26.2%) were interspecific hybrids, while 20 (90.9%) samples were surprisingly characterized as post-F1 hybrids. This result confirms that hybrids are sold in markets without adequate labeling and also indicates the lack of proper control of the commercialization and management of stocks and products in fish farms. In addition, we determined that molecular diagnosis was an extremely effective and necessary method to test the reliability of biological materials currently used in scientific research.

Ecological divergence and hybridization of Neotropical Leishmania parasites.

The tropical Andes are an important natural laboratory to understand speciation in many taxa. Here we examined the evolutionary history of parasites of the Leishmania braziliensis species complex based on whole-genome sequencing of 67 isolates from 47 localities in Peru. We first show the origin of Andean Leishmania as a clade of near-clonal lineages that diverged from admixed Amazonian ancestors, accompanied by a significant reduction in genome diversity and large structural variations implicated in host-parasite interactions. Within the Andean species, patterns of population structure were strongly associated with biogeographical origin. Molecular clock and ecological niche modeling suggested that the history of diversification of the Andean lineages is limited to the Late Pleistocene and intimately associated with habitat contractions driven by climate change. These results suggest that changes in forestation over the past 150,000 y have influenced speciation and diversity of these Neotropical parasites. Second, genome-scale analyses provided evidence of meiotic-like recombination between Andean and Amazonian Leishmania species, resulting in full-genome hybrids. The mitochondrial genome of these hybrids consisted of homogeneous uniparental maxicircles, but minicircles originated from both parental species. We further show that mitochondrial minicircles-but not maxicircles-show a similar evolutionary pattern to the nuclear genome, suggesting that compatibility between nuclear-encoded mitochondrial genes and minicircle-encoded guide RNA genes is essential to maintain efficient respiration. By comparing full nuclear and mitochondrial genome ancestries, our data expand our appreciation on the genetic consequences of diversification and hybridization in parasitic protozoa.

Interspecific hybridization improves the performance of Lotus spp. under saline stress.

Salinity is one of the most frequent limiting conditions in pasture production for grazing livestock. Legumes, such as Lotus spp. with high forage quality and capable of adapting to different environments, improves pasture performance in restrictive areas. In order to determine potential cultivars with better forage traits, the current study assess the response to salt stress of L. tenuis, L. corniculatus and a novel L. tenuis x L. corniculatus accession. For this purpose, chlorophyll fluorescence, biomass production, ion accumulation and anthocyanins and proanthocyanidins levels have been evaluated in control and salt-treated plants PSII activity was affected by salt in L. tenuis, but not in L. corniculatus or hybrid plants. Analyzed accessions showed similar values of biomass, Na+ and K+ levels after salt treatment. Increasing Cl- concentrations were observed in all accessions. However, hybrid plants accumulate Cl- in stems at higher levels than their parental. At the same time, the levels of anthocyanins considerably increased in L. tenuis x L. corniculatus stems. Chloride and anthocyanin accumulation in stems could explain the best performance of hybrid plants after a long saline treatment. Finally, as proanthocyanidins levels were no affected by salt, L. tenuis x L. corniculatus plants maintained adequate levels to be used as ruminant feed. In conclusion, these results suggest that hybrid plants have a high potential to be used as forage on salt-affected lands. High Cl- and anthocyanins accumulation in Lotus spp. stems seems to be a trait associated to salinity tolerance, with the possibility of being used in legume breeding programs.

Reação de híbridos interespecíficos de Passiflora spp. à Xanthomonas axonopodis pv. passiflorae / Reaction of interspecific hybrids of Passiflora spp. to Xanthomonas axonopodis pv. passiflorae

Avaliou-se o grau de resistência de 36 clones de maracujazeiro obtidos por seleção massal de sete progênies de híbridos interespecíficos a três isolados de Xanthomonas axonopodis pv. passiflorae. As progênies foram obtidas por meio de cruzamentos entre a cultivar comercial Passiflora edulis "flavicarpa" com as espécies silvestres P. caerulea, P. edulis "roxo" e P. setacea. Os isolados da bactéria foram obtidos em Rio Claro-SP, Planaltina-DF e Limeira-SP. Clones individuais foram inoculados com solução bacteriana na concentração de 108ufc ml-1 aos 120 dias da semeadura. As avaliações ocorreram aos 5, 10 e 15 dias após a inoculação, medindo-se o diâmetro longitudinal e transversal das lesões. Em seguida, calculou-se a área abaixo da curva de progresso da lesão (AACPL). O delineamento experimental foi em blocos ao acaso com parcelas subdivididas, sendo os genótipos os tratamentos distribuídos em quatro blocos com parcelas de três plantas para cada genótipo. Em cada parcela, plantas individuais foram inoculadas com um dos isolados da bactéria, totalizando três plantas com isolados diferentes. Plantas das espécies genitoras P. caerulea (AACPL=0,17) e P. setacea (AACPL=14,50) apresentaram alto grau de resistência, quando comparadas às plantas da testemunha BRS Gigante Amarelo (AACPL=4089,25), enquanto genótipos híbridos apresentaram valores intermediários (AACPL de 15,67 a 768,42), indicando a importância desses materiais como fontes de resistência à bacteriose.(AU)

The aim of this study was to evaluated the degree of resistance of 36 clones of passion obtained through mass selection progenies of seven interspecific hybrids, to three different isolates of X. axonopodis pv. passiflorae. The progenies were obtained by crossing among a commercial cultivate Passiflora edulis "yellow passion fruit" with wild species P. caerulea, P. edulis "purple passion fruit" and P. setacea. The bacterial isolates used were obtained in Rio Claro,SP, Planaltina,DF and Limeira,SP. Individual cloned were inoculated with bacterial solution in concentration with 108cfu ml-1 to 120 days of sowing. Symptoms were evaluated at 5, 10 and 15 days after inoculation, by measuring the longitudinal and transverse diameter of the lesion. Then, it was calculated the area under the lesion progress curve (AUPLC). A complete randomized block design with split plots was used, the treatments were the tested genotypes replicated in four blocks. All genotypes in each block had a three-plant plot. The bacterial isolates were inoculated in one plant of the plot, totaling three plants with different isolates. The plants of the genitors species P. caerulea (AUPLC=0.17) and P. setacea (AUPLC=14.50) presented high degree of resistance when compared to control plants BRS 'Gigante Amarelo' (AUPLC=4089.25), while hybrids genotypes presented intermediary values (AUPLC of 15.67 the 768.42), showing the importance of these wild Passiflora species as source of resistance to bacterial disease.(AU)

Reação de híbridos interespecíficos de Passiflora spp. à Xanthomonas axonopodis pv. passiflorae / Reaction of interspecific hybrids of Passiflora spp. to Xanthomonas axonopodis pv. passiflorae

Avaliou-se o grau de resistência de 36 clones de maracujazeiro obtidos por seleção massal de sete progênies de híbridos interespecíficos a três isolados de Xanthomonas axonopodis pv. passiflorae. As progênies foram obtidas por meio de cruzamentos entre a cultivar comercial Passiflora edulis "flavicarpa" com as espécies silvestres P. caerulea, P. edulis "roxo" e P. setacea. Os isolados da bactéria foram obtidos em Rio Claro-SP, Planaltina-DF e Limeira-SP. Clones individuais foram inoculados com solução bacteriana na concentração de 108ufc ml-1 aos 120 dias da semeadura. As avaliações ocorreram aos 5, 10 e 15 dias após a inoculação, medindo-se o diâmetro longitudinal e transversal das lesões. Em seguida, calculou-se a área abaixo da curva de progresso da lesão (AACPL). O delineamento experimental foi em blocos ao acaso com parcelas subdivididas, sendo os genótipos os tratamentos distribuídos em quatro blocos com parcelas de três plantas para cada genótipo. Em cada parcela, plantas individuais foram inoculadas com um dos isolados da bactéria, totalizando três plantas com isolados diferentes. Plantas das espécies genitoras P. caerulea (AACPL=0,17) e P. setacea (AACPL=14,50) apresentaram alto grau de resistência, quando comparadas às plantas da testemunha BRS Gigante Amarelo (AACPL=4089,25), enquanto genótipos híbridos apresentaram valores intermediários (AACPL de 15,67 a 768,42), indicando a importância desses materiais como fontes de resistência à bacteriose.

The aim of this study was to evaluated the degree of resistance of 36 clones of passion obtained through mass selection progenies of seven interspecific hybrids, to three different isolates of X. axonopodis pv. passiflorae. The progenies were obtained by crossing among a commercial cultivate Passiflora edulis "yellow passion fruit" with wild species P. caerulea, P. edulis "purple passion fruit" and P. setacea. The bacterial isolates used were obtained in Rio Claro,SP, Planaltina,DF and Limeira,SP. Individual cloned were inoculated with bacterial solution in concentration with 108cfu ml-1 to 120 days of sowing. Symptoms were evaluated at 5, 10 and 15 days after inoculation, by measuring the longitudinal and transverse diameter of the lesion. Then, it was calculated the area under the lesion progress curve (AUPLC). A complete randomized block design with split plots was used, the treatments were the tested genotypes replicated in four blocks. All genotypes in each block had a three-plant plot. The bacterial isolates were inoculated in one plant of the plot, totaling three plants with different isolates. The plants of the genitors species P. caerulea (AUPLC=0.17) and P. setacea (AUPLC=14.50) presented high degree of resistance when compared to control plants BRS 'Gigante Amarelo' (AUPLC=4089.25), while hybrids genotypes presented intermediary values (AUPLC of 15.67 the 768.42), showing the importance of these wild Passiflora species as source of resistance to bacterial disease.

Microsporogenesis in Brachiaria dictyoneura (Fig. & De Not.) Stapf (Poaceae: Paniceae)

icrosporogenesis was analyzed in five accessions of Brachiaria dictyoneura presenting x = 6 as the basic chromosome number. All accessions were tetraploid (2n = 4x = 24) with chromosome pairing in bi-, tri-, and quadrivalents. The recorded meiotic abnormalities were those typical of polyploids, including precocious chromosome migration to the poles, laggard chromosomes, and micronucleus formation. The frequency of these abnormalities, however, was lower than those reported for other polyploid accessions previously analyzed for other Brachiaria species. Cell fusion and absence of cytokinesis were also recorded in some accessions, leading to restitutional nucleus formation in some cells. Genetically unbalanced microspores, binucleate, and 2n microspores were found among normal meiotic products as results from these abnormalities. The limitation in using these accessions as pollen donor in interspecific crosses with sexual species with x = 7 or x = 9 in breeding programs is discussed.