Taxonomic decisions within the order Rhizobiales have relied heavily on the interpretations of highly conserved 16S rRNA sequences and DNA–DNA hybridizations (DDH). Currently, bacterial species are defined as including strains that present 95–96% of average nucleotide identity (ANI) and 70% of digital DDH (dDDH). Thus, ANI values from 520 genome sequences of type strains from species of Rhizobiales order were computed. From the resulting 270,400 comparisons, a ≥95% cut-off was used to extract high identity genome clusters through enumerating maximal cliques. Coupling this graph-based approach with dDDH from clusters of interest, it was found that: (i) there are synonymy between Aminobacter lissarensis and Aminobacter carboxidus, Aurantimonas manganoxydans and Aurantimonas coralicida, “Bartonella mastomydis,” and Bartonella elizabethae, Chelativorans oligotrophicus, and Chelativorans multitrophicus, Rhizobium azibense, and Rhizobium gallicum, Rhizobium fabae, and Rhizobium pisi, and Rhodoplanes piscinae and Rhodoplanes serenus; (ii) Chelatobacter heintzii is not a synonym of Aminobacter aminovorans; (iii) “Bartonella vinsonii” subsp. arupensis and “B. vinsonii” subsp. berkhoffii represent members of different species; (iv) the genome accessions GCF_003024615.1 (“Mesorhizobium loti LMG 6,125T”), GCF_003024595.1 (“Mesorhizobium plurifarium LMG 11,892T”), GCF_003096615.1 (“Methylobacterium organophilum DSM 760T”), and GCF_000373025.1 (“R. gallicum R-602 spT”) are not from the genuine type strains used for the respective species descriptions; and v) “Xanthobacter autotrophicus” Py2 and “Aminobacter aminovorans” KCTC 2,477T represent cases of misuse of the term “type strain”. Aminobacter heintzii comb. nov. and the reclassification of Aminobacter ciceronei as A. heintzii is also proposed. To facilitate the downstream analysis of large ANI matrices, we introduce here ProKlust (“Prokaryotic Clusters”), an R package that uses a graph-based approach to obtain, filter, and visualize clusters on identity/similarity matrices, with settable cut-off points and the possibility of multiple matrices entries.

SUMMARYUnderstanding the magnitude of B mobility in eucalyptus may help to select clones that are more efficient for B use and to design new practices of B fertilization. This study consisted of five experiments with three eucalyptus clones (129, 57 and 58) where the response to and mobility of B were evaluated. Results indicated that clone 129 was less sensitive to B deficiency than clones 68 and 57, apparently due to its ability to translocate B previously absorbed via root systems to younger tissues when B in solution became limiting. Translocation also occurred when B was applied as boric acid only once to a single mature leaf, resulting in higher B concentration in roots, stems and younger leaves. The growth of B-deficient plants was also recovere by a single foliar application of B to a mature leaf. This mobility was greater, when foliar-applied B was supplied in complexed (boric acid + manitol) than in non-complexed form (boric acid alone). When the root system of clone 129 was split in two solution compartments, B supplied to one root compartment was translocated to the shoot and back to the roots in the other compartment, improving the B status and growth. Thus, it appears that B is relatively mobile in eucalyptus, especially in clone 129, and its higher mobility could be due to the presence of an organic compound such as manitol, able to complex B.Index terms: micronutrient, forest nutrition, translocation, polyol.(

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The nature of the soil is shaped by the presence of roots and the soil microbiota. Bacteria, archaea and fungi profoundly alter plant growth and, in turn, depend on root exudation of carbon-rich and energy-yielding compounds. The microbial communities act as facilitators of plant processes by secreting plant growth regulators, solubilizing minerals, providing N for plant growth, altering plant immune responses and competing with plant pathogens. Characterizing and engineering the processes driven by the multiple microbial taxa that make up a "plant growth-promoting soil" represents an ecologically friendly solution that may lead to unprecedented increases in agronomic efficiency. This review outlines the characteristics of soil-plant-microbiota interactions that would lead to enhanced plant growth and the importance of characterizing the soil microbial communities with metabarcoding and shotgun metagenomics allied to machine learning analytics. Although much is still needed to be understood about soil microbial ecology, it is possible to choose the best soil management practices to take advantage of beneficial microbial activity with our current knowledge.

Resumo O objetivo deste estudo foi avaliar o desenvolvimento, em altura (m), DAP (cm) e produção de madeira (m 3 /ha) aos 96 meses de idade após o plantio, das espécies Acacia mearnsii De Wild e Eucalyptus globulus Labill em monocultivos e consórcios com linhas simples e duplas de plantio, no estado do Rio Grande do Sul-RS. O experimento foi instalado no ano de 2005, em duas fazendas localizadas no município de Piratini-RS, onde foram plantadas as espécies Eucalyptus globulus Labill (E) e Acacia mearnsii De Wild (A), em monocultivo (100%E e 100%A) e consorciadas em linhas simples (50%E:50%A-LS) e em linhas duplas (50%E:50%A-LD). Para avaliarmos os efeitos dos consórcios no desenvolvimento das espécies, o crescimento foi avaliado anualmente nos meses de outubro entre 2006 e 2013; e no ano de 2014 foi realizada a cubagem pelo método de Smalian. A acácia-negra teve seu crescimento em altura beneficiado pelo consórcio, 13,96 m no 50%E:50%A-LS e 13,56 m no 50%E:50%A-LD, enquanto que na monocultura apresentou uma altura de 13,23 m, já para o eucalipto não foi possível observar vantagens no crescimento em altura, pois os consórcios foram iguais ao monocultivo; o DAP para ambas espécies foi influenciado pelos consórcios, positivamente para a acácia-negra, sendo até 15% superior ao monocultivo, e negativamente para o eucalipto, chegando a ser 17% inferior ao monocultivo, diferenças que são explicadas pelas variações dos espaçamentos proporcionadas ao se manter o arranjo convencional de plantio das espécies nos tratamentos consorciados. A produção de madeira da acácia negra nos consórcios (97,97 m 3 /ha no 50%E:50%A-LS e 90,93 m 3 /ha no 50%E:50%A-LD) foi superior a 50% a da monocultura (136,11 m 3 /ha), o que não ocorreu para o eucalipto. As produções totais dos consórcios foram iguais estatisticamente as das monoculturas.