ABSTRACT This was the first study conducted on the diversity and abundance of arbuscular mycorrhizal fungi (AMF) species and quantification of glomalin-related soil protein (GRSP) fractions, as well as on their relationship with environmental and soil chemical and physical properties along an elevation gradient above 1000 m in a Brazilian Atlantic cloud forest. AMF diversity was assessed by examining spores extracted from soil samples collected near the roots of the 18 most common plant species in permanent plots established in the field at altitudes of 1500, 1700, 1900, and 2100 meters above sea level. Fifteen AMF species were found, most of them belonging to the families Acaulosporaceae, Glomeraeceae, and Gigasporaceae. Compositions of the AMF community varied among the altitudes; Acaulospora was the predominant genus, with six species. The total Bradford-reactive soil protein (BRSP) and the easily extractable BRSP (EE-BRSP) soil glomalin were the highest at the altitude of 2100 m (5.7 and 3.8 mg.g soil-1, respectively). Altitude and environment and soil characteristics affected the composition and diversity (Shannon index) of the AMF communities. However, the effect of altitude on AMF diversity can be estimated, indirectly, through its effect on plant diversity. (AMF glomalinrelated related GRSP (GRSP fractions 100 forest 1 1500 1700 1900 210 level found Acaulosporaceae Glomeraeceae Gigasporaceae genus Bradfordreactive Bradford reactive (BRSP EEBRSP EE (EE-BRSP 5.7 57 5 7 (5. 38 3 8 3. mgg mg g soil1, soil1 1, soil-1 respectively. respectively . respectively) Shannon index communities However estimated indirectly 10 150 170 190 21 5. (5 soil- 15 17 19 2 (

Abstract One of the most widespread applications of poly(lactic acid) (PLA) is as a raw material in the form of filaments for 3D printing. To improve final disposal alternatives and minimize their effects on the environment, the aim of this study is to determine the biodegradability of 3D-printed PLA waste composted in a landfill with leachate soil and garden soil for 90 days and 180 days. The soil characteristics and material properties were evaluated by laboratory analyses. Changes in soil chemical composition and the loss of microorganisms were recorded. The thermal and mechanical properties of PLA did not change significantly, but fungal colonies, encrustation, and changes in the original colour were found, indicating the onset of surface biodegradation of the samples. Controlled conditions or longer periods would be needed to maintain an ecosystem favourable to biodegradation; otherwise, PLA could accumulate in the environment, causing future pollution problems. polylactic poly lactic acid (PLA D printing environment 3Dprinted Dprinted printed 9 18 analyses recorded significantly colonies encrustation found samples otherwise problems 1

ABSTRACT The use of Stizolobium aterrimum (velvet bean) as green manure has been encouraged in agriculture as a source of nitrogen-rich phytomass for incorporation into the soil to enhance subsequent crop yield. The nitrogen-fixing capacity of this legume can be optimized through symbiosis with selected strains of rhizobia. The aim of this study was to evaluate the effectiveness of new strains of Bradyrhizobium in promoting the growth of velvet bean plants, both in potted soil and in the field. The study involved three experiments (two in pots and one in the field) with four replications of each in an Oxisol. An additional experiment was carried out to estimate the native rhizobial community in the experimental soil. The efficiency of the strains was estimated by compared plant growth with them to plant growth in two non-inoculated controls (one without mineral N and the other with mineral N) and plant growth with the strain BR2811, which is approved as an inoculant for velvet bean plants. Evaluations of velvet bean were performed at 60 and 100 days after emergence in non-sterile soil pots, and at 170 days after sowing (at flowering) in the field. Native rhizobia are efficient in symbiosis with velvet bean, as they were similar to BR2811 and to the control with mineral N, but they had lower biological nitrogen fixation efficiency than the new strains tested–UFLA05-18 and UFLA05-20. The new strains increased velvet bean yield and accumulation of N in velvet bean phytomass and, therefore, have potential for being used as inoculants for this species. nitrogenrich rich nitrogenfixing fixing plants field Oxisol noninoculated non inoculated BR 6 10 nonsterile sterile 17 flowering BR281 tested–UFLA0518 testedUFLA0518 testedUFLA tested–UFLA05 18 tested UFLA05 UFLA tested–UFLA05-1 UFLA0520. UFLA0520 20. 20 UFLA05-20 therefore species 1 BR28 UFLA0518 tested–UFLA051 testedUFLA051 testedUFLA05 tested–UFLA0 UFLA0 tested–UFLA05- UFLA052 2 UFLA05-2 BR2 UFLA051 testedUFLA0 tested–UFLA UFLA05-

Abstract The threatened orchid Cattleya milleri is a microendemic orchid of a Brazilian savanna hotspot. As endophytes and mycorrhizae may improve its propagation and conservation, we investigated its root fungal community. Cattleya milleri roots were sampled in five natural sites and at a greenhouse. Fungal root endophytes were isolated for characterization and molecular ITS (Internal Transcribed Spacer) identification. Total DNA was extracted from endorhiza and rhizosphere for ITS amplification and sequencing. Sixteen fungal isolates were clustered in 6 Operational Taxonomic Units (OTUs) and endorhizal and rhizospheric sequences were clustered in 327 OTUs. Endorhiza presented from 25 to 89 OTUs, and rhizosphere 56 OTUs. Cluster analysis showed high divergence between natural and greenhouse fungal communities, but similarity among natural samples. From the 94 genera, 24 were annotated as endophytes, two mycorrhizas, 33 pathotrophs, 40 saprotrophs, and 17 symbiotrophs based on the FunGuild database. Endophytes of the orders Capnodiales, Hypocreales, Pleosporales, and mycorrhizae of Sebacinales occurred in all sites. The mycorrhizae Tulasnella occurred in all natural samples. The interaction with only two mycorrhizal taxa may limit C. milleri distribution. However, the recruitment of many non-mycorrhizal endophytes is essential to natural development. Pleosporales, Tulasnella, and Sebacinalles may be considered for C. milleri propagation and conservation. hotspot conservation community Internal Spacer identification sequencing OTUs (OTUs 32 2 8 5 communities samples 9 genera mycorrhizas 3 pathotrophs 4 saprotrophs 1 database Capnodiales Hypocreales Pleosporales C distribution However nonmycorrhizal non development

ABSTRACT: We evaluated the compatibility between two nitrogen–fixing Bradyrhizobium inoculant strains and phosphate–solubilizing fungal strains and the effect of co–inoculation of these bacterial and fungal strains on cowpea growth under different N and P conditions. First, the compatibility between Bradyrhizobium strains UFLA03–84 and INPA03–11B and fungi Haematonectria ipomoeae FSA381, Eleutherascus lectardii FSA257a, Pochonia chlamydosporia var. catenulata FSA109, and Acremonium polychromum FSA115 was tested in both solid and liquid media. Cowpea growth and nodulation promotion under two mineral N doses and two P conditions (a low dose of soluble P plus a high dose of Ca3(PO4)2 and another condition with a high dose of soluble P) were tested with two N2 fixing Bradyrhizobium strains co–inoculated with each of the P–solubilizing fungal strains FSA109, FSA115, and FSA381. There was compatibility between each fungal strain and the two Bradyrhizobium strains, except for FSA257a with either of the bacterial strains in liquid medium. When both mineral N and P were limiting, plants were able to grow and accumulate N and P based on biological N2 fixation and solubilization of calcium phosphate in the same amount as the mineral N and soluble phosphate. Even when both nutrients were fully available, the type of co–inoculation promoted plant growth and nutrient accumulation. The responses varied in accordance with the co–inoculated strains, the N source, and the P source, reflecting the enormous complexity of the biological interactions between plants and microorganisms, and the nutrient conditions provided by the environment.

ABSTRACT. The BRSMG Uai common bean cultivar (Phaseolus vulgaris L.) unites traits required by producers, such as high yield and upright stands, the latter of which is considerably improved in relation to previously released cultivars such as BRSMG Madrepérola and Pérola. However, the potential of the cultivar to form symbiotic relationships with rhizobia to fix N2 has not yet been assessed. Here, field experiments were conducted to assess the efficiency of biological nitrogen fixation (BNF) in the cultivar, and to compare this to the efficiencies of other genetic materials widely grown throughout Brazil (BRSMG Madrepérola and Pérola). Experiments were conducted on two Oxisols in Minas Gerais State, Brazil (one during the dry season in the south, and the other during the winter season in the Alto-Paranaíba region), under a no-tillage system over maize stover. A randomized block experimental design was implemented in a 3 × 3 factorial arrangement with four replicates. Individual and combined Analysis of Variance were performed and the data were normalized. Homogeneity of the residual mean squares was observed. Significant effects of factors were identified by Scott-Knott tests and F tests. The BRSMG Uai cultivar responded to inoculation with the rhizobial strain CIAT 899, with yields similar to those achieved upon fertilization with 80 kg ha-1 of N-urea and to the yields of the BRSMG Madrepérola and Pérola cultivars inoculated with the same rhizobial strain. In terms of commercial use, this cultivar may be successful under either of the management practices adopted for N supply, and from the perspective of plant breeding, it has potential for inclusion in breeding programs directed toward improving BNF.

ABSTRACT: Identification and selection of nitrogen-fixing bacterial strains for inoculation into native leguminous tree species can assist in the recovery of degraded areas. Additionally, native strains from these areas are genetic resources adapted to these conditions and are thus suitable for selection. The aim of this study was to symbiotically and genetically characterize 18 bacterial strains from the Rhizobium and Bradyrhizobium genera isolated from Machaerium nyctitans, Platypodium elegans, and Ormosia arborea grown in a nursery in an iron mining area. Three experiments were conducted under axenic conditions in a greenhouse. The nodulation capacity of the strains was evaluated by the number (NN) and dry matter (NDM) of nodules. Symbiotic efficiency was evaluated based on the following parameters: SPAD index (SPAD), shoot dry matter (SDM), root dry matter (RDM), and total dry matter (TDM) of the plants, relative efficiency (RE), shoot nitrogen content (SNC), and total nitrogen content in the plant (TNC). The atpD and gyrB housekeeping genes and the nifH gene were sequenced for phylogenetic analysis, and the nodC and nodD symbiotic genes of the strains were amplified. Out of the 18 strains, 16 were authenticated by nodulation capacity in the species of origin. The SPAD variable allowed for the detection of differences between treatments before the SDM. Additionally, the SPAD index showed correlation with TNC, and the strain Bradyrhizobium sp., UFLA01-839, which may represent a new species, was outstanding in Machaerium nyctitans. The nifH, nodD, and nodC genes were detected in UFLA01-839.

ABSTRACT In spite of the chemical, physical, and biological benefits that Crotalaria spectabilis can provide to the soil, it is little used as a green manure crop by farmers. Inoculation with strains of legume-nodulating nitrogen-fixing bacteria that are efficient and competitive may be a strategy to enhance accumulation of N in C. spectabilis and stimulate adoption of this green manure crop. The aims of this study were i) to evaluate the symbiotic and agronomic efficiency of new strains of Bradyrhizobium on C. spectabilis in an oxisol (red latosol) compared to that of noninoculated controls (without and with mineral N) and with the approved strain BR2811, seeking to corroborate possible recommendation as inoculants for this species; and ii) to determine, the contribution of these treatments to N accumulation in the plant of C. spectabilis in four periods of cutting for determining possible and ideal periods for its incorporation in the soil. Experiments were carried out in pots and field. Inoculation with the new strains UFLA05-03, UFLA05-09, and UFLA05-14 and with BR2811 on C. spectabilis is effective since it increases the production of N-enriched plant biomass when compared to the control without N mineral. However, UFLA05-03 stands out among these strains because it behaves similarly to the control with mineral N both in relation to shoot N accumulation and dry matter just after 150 days in the field.

ABSTRACT. Agar media with insoluble phosphates are used for semi-quantitative screening of phosphate-solubilizing bacteria based on the solubilization halo formed around the colonies. We show that the volume of the culture medium (15, 20, and 30 mL) and the inoculation method (toothpick vs microdrop) strongly influence the diameter of the solubilization halo, and this should be considered in advance selection of the isolates most efficient in this process.

RESUMO Mimosa foliolosa Mimosa foliolosa é uma espécie nativa de campos rupestres promissora para revegetação de áreas degradadas neste ecossistema. A simbiose entre leguminosas e bactérias fixadoras de N2 pode desempenhar um papel importante na recuperação dessas áreas, uma vez que estas plantas têm melhor desenvolvimento e são mais resistentes ao ataque de patógenos. Em adição à fixação biológica de N2 (-FBN), essas bactérias podem promover o crescimento vegetal por meio de outros processos, tais como solubilização de fosfatos e produção de sideróforos. Nós estudamos as características culturais e genéticas de 11 estirpes de bactérias isoladas de solo de campos rupestres utilizando Mimosa tenuiflora como planta isca. Nós avaliamos estas estirpes em relação as suas características simbióticas como nodulação e promoção de crescimento de Mimosa foliolosa, assim como sua habilidade de solubilizar fosfato e produzir sideróforos. Estirpes bacterianas fixadoras de N2 nativas pertencentes ao gênero Paraburkholderia (UFLA01-750, UFLA01-728, UFLA01-725 e UFLA01-757), apresentaram alta eficiência simbiótica com M. foliolosa, além de solubilizar fosfato de cálcio e produzir sideróforos, evidenciando uma alta diversidade funcional e potencial para uso em projetos de revegetação.

ABSTRACT Mimosa foliolosa is a promising native species of rupestrian fields for revegetation of degraded areas in this ecosystem. The symbiosis between leguminous plants and N2-fixing bacteria may play an important role in the recovery of these areas, since these plants have better development and are more resistant to the attack of pathogens. In addition to the biological nitrogen fixation (BNF), these bacteria can promote plant growth through other processes, such as phosphate solubilization and siderophore production. We studied the cultural and genetic characteristics of 11 bacterial strains, isolated from rupestrian field soils using Mimosa tenuiflora as “trap” plant. We evaluated these strains considering their symbiotic characteristics such as nodulation, and growth-promotion of Mimosa foliolosa, as well as their ability for siderophore production and phosphate solubilization. Native N2-fixing bacterial strains belonging to the Paraburkholderia genus (UFLA01-750, UFLA01-728, UFLA01-725, and UFLA01-757), showed high symbiotic efficiency with M. foliolosa. These strains also solubilized calcium phosphate and produced siderophores, exhibiting high functional diversity and potential for use in revegetation projects.

ABSTRACT Studies in the Amazon indicate a wide diversity of rhizobia with the ability for biological nitrogen fixation (BNF), which could expand the number of strains approved for cowpea. Thus, the aim of this field study was to evaluate the agronomic performance in cowpea of the several strains isolated from the soils of the Brazilian states Acre and Rondônia, and to compare them withstrains approved by the Ministry of Agriculture (MAPA) and withnon-inoculated controls (without and with mineral nitrogen fertilizer). The inoculants performed well. Though less effective than the other strains, the UFLA 03-36 strain also was prominent with respect to grain yield. Because of the positive response of the UFLA 03-129 strain, which led to yield increases greater than the obtained from the control without inoculation plus mineral-N, it can be recommended as an inoculum for cowpea. Further investigations should be carried out to obtain MAPA’s approval for their use. Other experiments involving this strain and several cultivars are being carried out on other types of soil and environmental conditions of the state of Minas Gerais.

ABSTRACT: A significant number of bacterial species, particularly in the rhizosphere, may benefit plant growth and development. This group of bacteria is known as plant growth-promoting rhizobacteria (PGPR). This study identified genetically isolates of common bean nodules used to trap bacteria from Amazon pastureland and investigated their capacity of nodulating and promoting growth of common bean when inoculated or co-inoculated with CIAT899 strain (Rhizobium tropici). Two experiments were carried out in a greenhouse, in axenic conditions, using the common bean cultivar Talismã. In the first experiment, 56 PGPR strains were evaluated individually regarding growth promotion and nodulation. In the second experiment, inoculation of seven PGPR strains previously selected in the first experiment was evaluated in three forms of N supply: Co-inoculation with CIAT 899 in the presence of low N-mineral concentration; individual inoculation in the presence of high N-mineral concentration; and individual inoculation in the presence of low N-mineral concentration. The 16S rRNA gene sequencing showed predominance of Pseudomonas genus, identified in 35 % of the sequenced strains. Other genera were identified: Rhizobium, Burkholderia, Xanthomonas and Bacillus. Inoculation of the seven strains with CIAT 899 promoted distinct plant growth in different forms of N supply. In addition, N-mineral supply can be replaced by co-inoculation with strains of Pseudomonas sp. (UFLA 02-281 and UFLA 02-293) and Bacillus sp. (UFLA 02-298) identified in this study.

ABSTRACT: Among soil microorganisms, the genus Cupriavidus has garnered particular scientific, economic and ecological interest because of its ability to fix nitrogen and tolerate high concentrations of metals. The aim of this study was to analyze four strains of Cupriavidus necator for their ability to tolerate and bioaccumulate cadmium and zinc. The tolerance of these strains to these metals was assessed in liquid culture medium containing different concentrations of Zn + Cd and in soil solutions and soils contaminated with multiple elements including Zn, Cd, Cu and Pb. The four strains showed high tolerance to Zn and Cd, both in culture medium and when inoculated into contaminated soil solutions or multi-element contaminated soil. The UFLA02-71 strain displayed the highest ability to bioaccumulate these metals. It was able to accumulate 93.76 µmol g cell−1 of Zn and 16.03 µmol g cell−1 of Cd when cultured in liquid medium with a total heavy metal concentration of 9,140 µmol L−1 (9,000 Zn + 140 Cd) and was able to accumulate 16.98 µmol g cell−1 of Cd in the soil solution. An increase in the pH of the culture medium resulting from the growth of the C. necator strains reduced the Zn2+ and Cd2+ ions in the medium and increased the concentrations of the ZnHPO4 and CdHPO4 species in solution. Thus, we concluded that they show great potential for use in the bioremediation of HM-contaminated areas.

RESUMO O uso de estimulantes para o estabelecimento de fungos micorrízicos arbusculares tem grande potencial em contribuir para a absorção de P pelas plantas. Objetivou-se avaliar a eficácia do isoflavonóide formononetina como estimulante da micorrização na cultura da soja, associada a adubação fosfatada, em dois Latossolos com teores de fósforo disponível médio (LPm) e baixo (LPb) no Cerrado piauiense. O delineamento experimental em cada solo foi em blocos casualizados no esquema fatorial 4×4, com quatro repetições. Os tratamentos foram constituídos por quatro doses de fósforo (0; 26,66; 40 e 80 kg ha-1 de P2O5) e quatro doses do isoflavonóide formononetina (0; 0,5; 0,9 e 1,8 g kg-1 de semente de soja). As variáveis avaliadas foram, o crescimento, a produção, a nodulação e taxa de colonização micorrízica da soja. Com exceção da taxa de colonização micorrízica no LPm, altura e número de vagens por planta de soja no LPb, as demais variáveis, não foram influenciados pela aplicação do isoflavonóide formononetina, em ambos os solos. A produtividade cresceu linearmente ao incremento das doses de fósforo no LPb, apresentando uma eficiência agronômica de ~15 kg ha-1 de grãos para cada kg ha-1 de P2O5 aplicado no solo.

ABSTRACT The use of stimulants in the establishment of arbuscular mycorrhizal fungi has great potential in contributing to P uptake by plants. This study aimed to evaluate the effect of isoflavonoid formononetin as mycorrhization stimulant on soybean associated with phosphate fertilizer in Oxisols with intermediate (OPi) and low (OPl) phosphorus availability, in the Cerrado region of Piauí. The experiment in each soil consisted of randomized blocks design in a 4×4 factorial scheme, with four replications. The treatments comprised of four phosphorus doses (0, 26.66, 40 and 80 kg ha-1 P2O5), and four isoflavonoid formononetin doses (0, 0.5, 0.9 and 1.8 g kg-1 soybean seeds). The variables evaluated were soybean growth, yield, nodulation and mycorrhizal colonization rate. With the exception of mycorrhizal colonization rate in OPi, plant height and number of pods per plant in OPl, the other variables were not affected by the application of isoflavonoid formononetin, in both soils. Yield linearly increased with increase in the phosphorus doses in OPl, and presented agronomic efficiency of ~15 kg ha-1 grain for each kg ha-1 P2O5 applied to the soil.

ABSTRACT Although the use of inoculants containing rhizobia is encouraged, there are no official recommendations for inoculation of snap bean. In this respect, the aim of this study was to evaluate the agronomic performance of Rhizobium strains in symbiosis with snap bean cultivars with different growth habits and crop cycles. The experiment was carried out in pots with soil in a greenhouse in the spring-summer season in Lavras, state of Minas Gerais, Brazil. A completely randomized experimental design was used, with 4 replications, in a 4 × 7 factorial arrangement involving four snap bean cultivars and seven treatments – five strains of Rhizobium (UFLA 02-100, UFLA 02-127, UFLA 04-173, CIAT 899, and PRF 81), plus two controls without inoculation (with and without 500 mg N-NH4NO3∙dm–3). We conclude that: i) while genetic differences were observed among cultivars with respect to nodulating capacity, in all cases significant benefits were observed from BNF inoculation and ii) inoculation with selected strains of Rhizobium, as well as fertilization with mineral N, favors plant growtht, snap bean yields, and accumulation of N in the pods and, therefore, can fully substitute nitrogen fertilization in snap bean grown under protected cultivation.