Leaf Transcriptome Of Two Highly Divergent Genotypes Of Urochloa Humidicola (poaceae), A Tropical Polyploid Forage Grass Adapted To Acidic Soils And Temporary Flooding Areas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Urochloa humidicola (Koronivia grass) is a polyploid (6x to 9x) species that is used as forage in the tropics. Facultative apospory apomixis is present in most of the genotypes of this species, although one individual has been described as sexual. Molecular studies have been restricted to molecular marker approaches for genetic diversity estimations and linkage map construction. The objectives of the present study were to describe and compare the leaf transcriptome of two important genotypes that are highly divergent in terms of their phenotypes and reproduction modes: the sexual BH031 and the aposporous apomictic cultivar BRS Tupi. Results: We sequenced the leaf transcriptome of Koronivia grass using an Illumina GAIIx system, which produced 13.09 Gb of data that consisted of 163,575,526 paired-end reads between the two libraries. We de novo-assembled 76,196 transcripts with an average length of 1,152 bp and filtered 35,093 non-redundant unigenes. A similarity search against the non-redundant National Center of Biotechnology Information (NCBI) protein database returned 65 % hits. We annotated 24,133 unigenes in the Phytozome database and 14,082 unigenes in the UniProtKB/Swiss-Prot database, assigned 108,334 gene ontology terms to 17,255 unigenes and identified 5,324 unigenes in 327 known metabolic pathways. Comparisons with other grasses via a reciprocal BLAST search revealed a larger number of orthologous genes for the Panicum species. The unigenes were involved in C4 photosynthesis, lignocellulose biosynthesis and flooding stress responses. A search for functional molecular markers revealed 4,489 microsatellites and 560,298 single nucleotide polymorphisms (SNPs). A quantitative real-time PCR analysis validated the RNA-seq expression analysis and allowed for the identification of transcriptomic differences between the two evaluated genotypes. Moreover, 192 unannotated sequences were classified as containing complete open reading frames, suggesting that the new, potentially exclusive genes should be further investigated. Conclusion: The present study represents the first whole-transcriptome sequencing of U. humidicola leaves, providing an important public information source of transcripts and functional molecular markers. The qPCR analysis indicated that the expression of certain transcripts confirmed the differential expression observed in silico, which demonstrated that RNA-seq is useful for identifying differentially expressed and unique genes. These results corroborate the findings from previous studies and suggest a hybrid origin for BH031.17Brazilian National Council for Scientific and Technological Development (CNPq) [478262/2004-3, 502336/2005-6, 482458/2007-0]Computational Biology Program from Coordination of Superior Level Staff Improvement [CAPES 15/2013]State of Sao Paulo Research Foundation (FAPESP) [2008/52197-4]FAPESP [2013/14903-2, 2013/20447-0]CNPq [150719/2015-9, 307430/2007-3]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Bactérias endofíticas associadas a Paspalum vaginatum Swartz com potencial para promoção de crescimento vegetal e biocontrole: Endophytic bacteria associated with Paspalum vaginatum Swartz with potential for plant growth promotion and biocontrol

Espécies de Paspalum são importantes constituintes nas pastagens nativas de regiões tropicais e subtropicais das Américas. Paspalum vaginatum é nativo de áreas litorâneas no Brasil e é amplamente utilizado em campos de golfe nos Estados Unidos devido sua robustez e tolerância a estresses abióticos como a seca, encharcamento e salinidade. Bactérias localizadas no interior dessa espécie vegetal (endofíticas) podem ser parcialmente responsáveis pela tolerância a essas condições extremas. O uso de bactérias capazes de promover o crescimento vegetal como inoculantes é uma estratégia ecologicamente correta para substituir os fertilizantes químicos e melhorar a produção vegetal. Este estudo objetivou isolar e avaliar o potencial de solubilização de fosfato inorgânico (SFI), fixação biológica de nitrogênio (FBN), produção de ácido 3-indolacético (AIA) e potencial antagônico contra fitopatógenos de bactérias endofíticas associadas a P. vaginatum. As bactérias foram isoladas de raízes e folhas de P. vaginatum e testadas in vitro para FBN, SFI, produção de AIA e antagonismo contra o fungo fitopatogênico Bipolaris sp.. Entre os 72 isolados bacterianos testados, 43 fixaram nitrogênio (59,7%), 28 solubilizam fosfato inorgânico (38,9%), 70 produziram AIA (97,2%), mesmo que em baixa quantidade, e 12 apresentaram potencial antagônico contra Bipolaris sp. (16,7%). As 24 bactérias com melhores resultados nos testes foram identificadas por sequenciamento do gene 16S rDNA. Os gêneros identificados foram Bacillus sp., Pantoea sp., Enterobacter sp., Agrobacterium sp., Pseudomonas sp., Staphylococcus sp. e Streptomyces sp.

Endophytic and rhizospheric bacteria associated with Paspalum atratum and its potential for plant growth promotion with different phosphate sources

The genus Paspalum belongs to the family Poaceae and has several species that are native to Brazil. The Paspalum Germplasm Bank (GB) of the Brazilian Agricultural Research Corporation comprises approximately 450 accessions from 50 species. Among these accessions, Paspalum atratum (BGP 308) has economic potential for forage purposes. However, the endophytic and rhizospheric microbial communities within this accession and their ability to promote plant growth remain unknown. The present study aimed to isolate the endophytic and rhizospheric bacteria associated with P. atratum and to assess their potential for plant growth improvement, so-called plant growth-promoting bacteria (PGPB). For the in vitro tests, the ability of nitrogen-fixing bacteria (NFB), phosphate solubilization (PS) and indoleacetic acid (IAA) production were evaluated. A total of 116 endophytic and rhizosphere bacteria were obtained from the isolation. In the in vitro tests, 43 (37.00%) of these isolates showed positive NFB, PS, and IAA results. These isolates were identified by 16S rDNA sequencing. The phosphate solubilization index (PSI) ranged from 2 to 3.61, all 43 strains performed biological nitrogen fixation and the IAA production ranged from 12.85 to 431.41 μg ml−1. Eight of these 43 isolates were evaluated in vivo in a greenhouse using P. atratum caryopsis. The pots were filled with soil prepared with three different phosphate sources and one control without phosphate. After growth, the plants were submitted to morphological, bromatological and chemical determination. Data were analyzed using analysis of variance (ANOVA) and principal component analysis (PCA). In the in vivo test, treatments 105 (Pseudomonas sp.) and 458 (Pseudomonas sp.) were the most significant for the crystalline phosphate source, 109 (Bacillus sp.) for the sedimentary phosphate source and, as for the soluble phosphate source most treatments that received bacterial isolates had higher phosphorus content in the dry matter than the uninoculated soluble phosphate control. The 105FCR (crystalline phosphate + Pseudomonas sp.), 109FSE (sedimentary phosphate + Bacillus sp.), and 110 FSE (sedimentary phosphate + Enterobacter sp.) treatments showed the best results for plant growth promotion. This work made it possible to determine the bacterial community associated with P. atratum (BGP308) and to obtain new potential plant growth-promoting strains

Recombinants from the crosses between amphidiploid and cultivated peanut (<i>Arachis hypogaea</i>) for pest-resistance breeding programs

<div><p>Peanut is a major oilseed crop worldwide. In the Brazilian peanut production, silvering thrips and red necked peanut worm are the most threatening pests. Resistant varieties are considered an alternative to pest control. Many wild diploid <i>Arachis</i> species have shown resistance to these pests, and these can be used in peanut breeding by obtaining hybrid of A and B genomes and subsequent polyploidization with colchicine, resulting in an AABB amphidiploid. This amphidiploid can be crossed with cultivated peanut (AABB) to provide genes of interest to the cultivar. In this study, the sterile diploid hybrids from <i>A</i>. <i>magna</i> V 13751 and <i>A</i>. <i>kempff-mercadoi</i> V 13250 were treated with colchicine for polyploidization, and the amphidiploids were crossed with <i>A</i>. <i>hypogaea</i> cv. IAC OL 4 to initiate the introgression of the wild genes into the cultivated peanut. The confirmation of the hybridity of the progenies was obtained by: (1) reproductive characterization through viability of pollen, (2) molecular characterization using microsatellite markers and (3) morphological characterization using 61 morphological traits with principal component analysis. The diploid hybrid individual was polyploidized, generating the amphidiploid An 13 (<i>A</i>. <i>magna</i> V 13751 x <i>A</i>. <i>kempff-mercadoi</i> V 13250)^4x. Four F₁ hybrid plants were obtained from IAC OL 4 × An 13, and 51 F₂ seeds were obtained from these F₁ plants. Using reproductive, molecular and morphological characterizations, it was possible to distinguish hybrid plants from selfed plants. In the cross between <i>A</i>. <i>hypogaea</i> and the amphidiploid, as the two parents are polyploid, the hybrid progeny and selves had the viability of the pollen grains as high as the parents. This fact turns the use of reproductive characteristics impossible for discriminating, in this case, the hybrid individuals from selfing. The hybrids between <i>A</i>. <i>hypogaea</i> and An 13 will be used in breeding programs seeking pest resistance, being subjected to successive backcrosses until recovering all traits of interest of <i>A</i>. <i>hypogaea</i>, keeping the pest resistance.</p></div

Order of descriptors that contributed most to the morphological variation observed in the principal component 1 (Prin 1) of the Principal Component Analysis of all the individuals evaluated in this work

<p>Order of descriptors that contributed most to the morphological variation observed in the principal component 1 (Prin 1) of the Principal Component Analysis of all the individuals evaluated in this work</p

Biplot graph resulting from the cross between IAC OL4 x An 13, obtained by Principal Component Analysis considering the 61 descriptors for the principal components 1 and 2.

<p>Triangle indicates female parents V 13751 (13) and IAC OL4 (11); circles, male parents V 13250 (14) and An 13 (12); and representing the progenies, square indicates the hybrid plants V 13751 x V 13250 (15) and IAC OL4 x An 13(1 to 4), and, diamonds, the plants derived from selfing IAC OL4 x An 13 (5 to 10).</p