Opposite Sides of Pantoea agglomerans and Its Associated Commercial Outlook.

Multifaceted microorganisms such as the bacterium Pantoea colonize a wide range of habitats and can exhibit both beneficial and harmful behaviors, which provide new insights into microbial ecology. In the agricultural context, several strains of Pantoea spp. can promote plant growth through direct or indirect mechanisms. Members of this genus contribute to plant growth mainly by increasing the supply of nitrogen, solubilizing ammonia and inorganic phosphate, and producing phytohormones (e.g., auxins). Several other studies have shown the potential of strains of Pantoea spp. to induce systemic resistance and protection against pests and pathogenic microorganisms in cultivated plants. Strains of the species Pantoea agglomerans deserve attention as a pest and phytopathogen control agent. Several of them also possess a biotechnological potential for therapeutic purposes (e.g., immunomodulators) and are implicated in human infections. Thus, the differentiation between the harmful and beneficial strains of P. agglomerans is mandatory to apply this bacterium safely as a biofertilizer or biocontroller. This review specifically evaluates the potential of the strain-associated features of P. agglomerans for bioprospecting and agricultural applications through its biological versatility as well as clarifying its potential animal and human health risks from a genomic point of view.

Draft genome sequence of the cyanobacterium Sphaerospermopsis aphanizomenoides BCCUSP55 from the Brazilian semiarid region reveals potential for anti-cancer applications.

Sphaerospermopsis aphanizomenoides is a filamentous nitrogen-fixing and bloom-forming cyanobacterium, which biomass can fertilize natural water with nutrients, especially through nitrogen fixation. The Sphaerospermopsis aphanizomenoides strain BCCUSP55 was previously isolated from a water supply reservoir in the Brazilian semiarid region, and its draft genome assembly coupled with the gene contents are reported here. The obtained BCCUSP55 draft genome comprised 254 scaffolds with a genome size estimated of 6,096,273 bp. In addition, it has 5250 predicted coding sequences (CDS) and the G + C content is 38.5%. Further, the BCCUSP55 draft genome presented the putative nocuolin A gene complete cluster, a natural oxadiazine that triggers apoptosis in human cancer cells. Thus, our results contribute to extend the knowledge on the genus Sphaerospermopsis and reveal its biotechnological potential.

Bacillus thuringiensis RZ2MS9, a tropical plant growth-promoting rhizobacterium, colonizes maize endophytically and alters the plant's production of volatile organic compounds during co-inoculation with Azospirillum brasilense Ab-V5.

The beneficial features of Bacillus thuringiensis (Bt) are not limited to its role as an insecticide; it is also able to promote plant growth interacting with plants and other plant growth-promoting rhizobacterium (PGPR). The PGPR Bt strain RZ2MS9 is a multi-trait maize growth promoter. We obtained a stable mutant of RZ2MS9 labelled with green fluorescent protein (RZ2MS9-GFP). We demonstrated that the Bt RZ2MS9-GFP successfully colonizes maize's roots and leaves endophytically. We evaluated whether RZ2MS9 has an additive effect on plant growth promotion when co-inoculated with Azospirillum brasilense Ab-V5. The two strains combined enhanced maize's roots and shoots dry weight around 50% and 80%, respectively, when compared to the non-inoculated control. However, non-differences were observed comparing RZ2MS9 alone and when co-inoculated with Ab-V5, In addition, we used co-inoculation experiments in glass chambers to analyse the plant's volatile organic compounds (VOCs) production during the maize-RZ2MS9 and maize-RZ2MS9-Ab-V5 interaction. We found that the single and co-inoculation altered maize's VOCs emission profile, with an increase in the production of indoles in the co-inoculation. Collectively, these results increase our knowledge about the interaction between the Bt and maize, and provide a new possibility of combined application with the commercial inoculant A. brasilense Ab-V5.

The auxin-producing Bacillus thuringiensis RZ2MS9 promotes the growth and modifies the root architecture of tomato (Solanum lycopersicum cv. Micro-Tom).

Strains of Bacillus thuringiensis (Bt) are commonly commercialized as bioinoculants for insect pest control, but their benefits go beyond their insecticidal property: they can act as plant growth-promoters. Auxins play a major role in the plant growth promotion. However, the mechanism of auxin production by the Bacilli group, and more specifically by Bt strains, is unclear. In previous work, the plant growth-promoting rhizobacterium (PGPR) B. thuringiensis strain RZ2MS9 increased the corn roots. This drew our attention to the strain's auxin production trait, earlier detected in vitro. Here, we demonstrate that in its genome, RZ2MS9 harbours the complete set of genes required in two pathways that are used for Indole acetic acid (IAA) production. We also detected that the strain produces almost five times more IAA during the stationary phase. The bacterial application increased the shoot dry weight of the Micro-Tom (MT) tomato by 24%. The application also modified MT root architecture, with an increase of 26% in the average lateral root length and inhibition of the axial root. At the cellular level, RZ2MS9-treated MT plants presented elongated root cortical cells with intensified mitotic activity. Altogether, these are the best characterized auxin-associated phenotypes. Besides that, no growth alteration was detected in the auxin-insensitive diageotropic (dgt) plants either with or without the RZ2MS9 inoculation. Our results suggest that auxins play an important role in the ability of B. thuringiensis RZ2MS9 to promote MT growth and provide a better understanding of the auxin production mechanism by a Bt strain.

Going Online in Pandemic Time: A DivulgaMicro Workshop Experience.

DivulgaMicro is a Brazilian science communication and outreach project run by three young female scientists. In 2020, due to the COVID-19 pandemic, we promoted the first virtual edition of the DivulgaMicro Workshop. Here, we describe adaptations implemented to deliver the virtual edition and its assessment by the participants. We offered a 3-day workshop addressing manuscript writing and publishing, poster design and oral presentations, and strategies for effectively communicating with the lay public on Days 1, 2, and 3, respectively. Each daily session was divided into short lectures and active learning through interactive and cooperative activities. We applied pre- and postsession surveys daily to assess participants' learning, with an opinion questionnaire at the end of the workshop. We selected 50 of 221 applicants, but only 38 of those selected participated in the workshop. Correct answers were significantly higher (p < 0.01) in the postsession surveys each day. Most of the 34 participants who answered the opinion questionnaire (97%) would recommend the workshop to their colleagues. Participants stated that the workshop content was transmitted in a clear and straightforward manner, and they considered the online format suitable for knowledge acquisition. Participants were satisfied with the organization, dynamics, and interactivity. Topics addressed on Day 3 (61.8%) and Day 1 (23.5%) were most liked and were considered most useful in the participants' careers. We believe that the overall success of the workshop is due to the combination of short lectures with active-learning activities, the use of virtual platforms that enabled effective communication between participants and instructors, and the support of our collaborators.

Complete Genome Sequence of Bacillus sp. Strain RZ2MS9, a Multitrait Plant Growth Promoter.

Here, we report the complete genome sequence of Bacillus sp. strain RZ2MS9, a plant growth-promoting bacterium isolated from the rhizosphere of guarana, a native crop from Amazonas, Brazil. The assembled genome comprises 5.35 Mbp, no plasmids, and a GC content of 35.22%.

Beneficial Plant-Associated Microorganisms From Semiarid Regions and Seasonally Dry Environments: A Review.

Semiarid regions are apparently low biodiversity environments; however, these environments may host a phylogenetically diverse microbial community associated with plants. Their microbial inhabitants are often recruited to withstand stressful settings and improve plant growth under harsh conditions. Thus, plant-associated microorganisms isolated from semiarid and seasonally dry environments will be detailed in the present review, focusing on plant growth promotion potential and the microbial ability to alleviate plant abiotic stress. Initially, we explored the role of microbes from dry environments around the world, and then, we focused on seasonally dry Brazilian biomes, the Caatinga and the Cerrado. Cultivable bacteria from semiarid and seasonally dry environments have demonstrated great plant growth promotion traits such as plant hormone production, mobilization of insoluble nutrients, and mechanisms related to plant abiotic stress alleviation. Several of these isolates were able to improve plant growth under stressful conditions commonly present in typical semiarid regions, such as high salinity and drought. Additionally, we highlight the potential of plants highly adapted to seasonal climates from the Caatinga and Cerrado biomes as a suitable pool of microbial inoculants to maintain plant growth under abiotic stress conditions. In general, we point out the potential for the exploitation of new microbial inoculants from plants growing in dry environments to ensure a sustainable increase in agricultural productivity in a future climate change scenario.

The Role of Non-Mycorrhizal Fungi in Germination of the Mycoheterotrophic Orchid Pogoniopsis schenckii Cogn.

Endophytic fungi are those that inhabit within organs and tissues without causing damage, while mycorrhizal fungi develop hyphal complexes called pelotons within cortical cells of orchid roots. Although abundant and frequent in all plant organs, the role of endophytic fungi has been neglected in relation to orchid's early development. Pogoniopsis schenckii Cogn. is an aclorophyllated and mycoheterotrophic (MH) orchid. This study aimed at i) investigating the endophytic fungal community in organs of P. schenckii and its mycorrhizal fungi associated; ii) evaluating the ability of isolated fungus in the in vitro germination of the seeds of the species, and iii) describing the development of P. schenckii protocorm, analyzing the ultrastructure of the infected cells. Six genera of fungi were isolated and identified through the partial sequencing of the internal transcribed spacer region, all belonging to the phylum Ascomycota. Also, Tulasnellaceae was identified through uncultured technique as potentially mycorrhizal in this MH orchid. Some isolates of the genera Trichoderma, Fusarium, and especially Clonostachys presented germinative potential on P. schenckii seeds, causing rupture of the external tegument. The protocorms showed complete absence of peloton formation, but fungal hyphae were clearly observed within living cells. This is the first report of germination of a MH and aclorophyllated orchid species stimulated by the presence of non-mycorrhizal endophytic fungi isolated from fruits and roots of the same species.

DivulgaMicro : A Brazilian Initiative To Empower Early-Career Scientists with Science Communication Skills.

Communication is fundamental in science. Among scientists, communication skills are required to write a comprehensible scientific manuscript or to prepare an attractive oral presentation. In addition, the ability to communicate successfully with the nonscientific community has been increasingly appreciated, as it represents the most effective way to promote popular scientific literacy. Nevertheless, students majoring in sciencerelated courses are not trained specifically for these purposes, and improving communication skills usually depends on tips and advice given by peers. To this end, we have launched DivulgaMicro, an initiative that aims to enhance science communication among early-career scientists in Brazil. DivulgaMicro relies on two major cornerstones: providing online resources via a dedicated website (www.divulgamicro.com.br/index.html) and promoting onsite workshops in universities located in different macro regions of the country. On the website, people can access a collection of fun activities designed to teach scientific concepts to a general audience, along with tips and news regarding public outreach events in Brazil. In the month following its launch, our website had 1,026 visitors from 10 different countries besides Brazil. Regarding the workshops, six were offered during 2018, with nearly 600 attendees. In the course, scientists are presented best practices for scientific writing and oral presentations, as well as techniques to improve communication with lay audiences, such as the use of storytelling structure and analogies. There is a high demand for science communication resources in Brazil, attesting to the importance of initiatives such as DivulgaMicro in our country.

A comunicação é fundamental para a ciência e a comunidade científica, cuja habilidade em se comunicar é necessária tanto para a escrita de um artigo científico quanto para a preparação de uma apresentação oral atrativa. Além disso, a capacidade de se comunicar de forma bem-sucedida com o público leigo tem sido cada vez mais apreciada, uma vez que representa a maneira mais eficaz em promover a alfabetização científica da população. No entanto, os estudantes que buscam se engajar na carreira científica não recebem treinamento específico nesse sentido, e o desenvolvimento dessa habilidade geralmente é dependente de dicas e conselhos recebidos de seus pares. Nesse contexto, foi criado o projeto DivulgaMicro, uma iniciativa que visa promover o desenvolvimento da comunicação científica entre jovens cientistas no Brasil. O projeto DivulgaMicro possui dois pilares principais: oferecer recursos online através do website http://www.divulgamicro.com.br/index.html e promover workshops de Comunicação e Divulgação Científica em universidades de diferentes macrorregiões do país. No website, as pessoas podem acessar e baixar uma coleção de atividades lúdicas destinadas ao ensino de conceitos científicos para o público em geral, incluindo crianças e adolescentes, além de dicas e novidades sobre divulgação científica no país. Após um mês de lançamento do projeto, o website do DivulgaMicro já havia recebido 1.026 acessos de 10 diferentes países além do Brasil. Em relação aos workshops, estão previstas seis edições em 2018 alcançando um público de cerca de 800 pessoas. No workshop, o participante é apresentado às melhores e mais eficazes práticas de escrita científica e apresentação oral, bem como técnicas para desenvolver e aprimorar a comunicação com o público leigo, incluindo como utilizar a estrutura storytelling e a aplicação de analogias. Atualmente no Brasil existe uma alta demanda em recursos e fontes de aprendizado em comunicação e divulgação científica, o que corrobora a relevância de iniciativas como o DivulgaMicro em nosso país.

Bacterial communities associated with anthracnose symptomatic and asymptomatic leaves of guarana, an endogenous tropical crop, and their pathogen antagonistic effects.

Plants are colonized by diverse microorganisms that can substantially impact their health and growth. Understanding bacterial diversity and the relationships between bacteria and phytopathogens may be key to finding effective biocontrol agents. We evaluated the bacterial community associated with anthracnose symptomatic and asymptomatic leaves of guarana, a typical tropical crop. Bacterial communities were assessed through culture-independent techniques based on extensive 16S rRNA sequencing, and cultured bacterial strains were evaluated for their ability to inhibit the growth of Colletotrichum sp. as well as for enzyme and siderophore production. The culture-independent method revealed that Proteobacteria was the most abundant phylum, but many sequences were unclassified. The emergence of anthracnose disease did not significantly affect the bacterial community, but the abundance of the genera Acinetobacter, Pseudomonas and Klebsiella were significantly higher in the symptomatic leaves. In vitro growth of Colletotrichum sp. was inhibited by 11.38% of the cultured bacterial strains, and bacteria with the highest inhibition rates were isolated from symptomatic leaves, while asymptomatic leaves hosted significantly more bacteria that produced amylase and polygalacturonase. The bacterial isolate Bacillus sp. EpD2-5 demonstrated the highest inhibition rate against Colletotrichum sp., whereas the isolates EpD2-12 and FD5-12 from the same genus also had high inhibition rates. These isolates were also able to produce several hydrolytic enzymes and siderophores, indicating that they may be good candidates for the biocontrol of anthracnose. Our work demonstrated the importance of using a polyphasic approach to study microbial communities from plant diseases, and future work should focus on elucidating the roles of culture-independent bacterial communities in guarana anthracnose disease.

Sugarcane must fed-batch fermentation by Saccharomyces cerevisiae: impact of sterilized and non-sterilized sugarcane must.

The presence of microbial contaminants is common in the sugarcane ethanol industry and can decrease process yield, reduce yeast cell viability and induce yeast cell flocculation. To evaluate the effect of microbial contamination on the fermentation process, we compared the use of sterilized and non-sterilized sugarcane must in the performance of Saccharomyces cerevisiae with similar fermentation conditions to those used in Brazilian mills. Non-sterilized sugarcane must had values of 103 and 108 CFU mL-1 of wild yeast and bacterial contamination, respectively; decreased total reducing sugar (TRS); and increased lactic and acetic acids, glycerol and ethanol concentrations during storage. During fermentation cycles with sterilized and non-sterilized sugarcane must, S. cerevisiae viability did not change, whereas ethanol yield varied from 74.1 to 80.2%, but it did not seem to be related to must microbial contamination. Ethanol productivity decreased throughout the fermentation cycles and was more pronounced in the last two fermentation cycles with non-sterilized must, but that may be related to the decrease in must TRS. High values of the ratio of total acid production per ethanol were reported at the end of the last two fermentation cycles conducted with non-sterilized must. Additionally, the values of wild yeast contamination increased from 102 to 103 CFU mL-1 and bacterial contamination increased from 104 to 106 CFU mL-1 when comparing the first and last fermentation cycles with non-sterilized must. In addition to the increase in microbial contamination and acid concentration, ethanol yield and yeast viability rates were not directly affected by the microbial contamination present in the non-sterilized sugarcane must.

Screening of tropically derived, multi-trait plant growth- promoting rhizobacteria and evaluation of corn and soybean colonization ability.

The present study assessed the plant growth-promoting (PGP) traits and diversity of culturable rhizobacteria associated with guarana (Paullinia cupana), a typical tropical plant. Ninety-six bacteria were isolated, subjected to biochemical tests, and identified by partial or total 16S rDNA sequencing. Proteobacteria and Firmicutes were the dominant rhizospheric phyla found, and Burkholderia and Bacillus were the most abundant genera. Thirteen strains exhibited the four PGP traits evaluated, and most of them belonged to the genus Burkholderia. Two multi-trait PGP strains, RZ2MS9 (Bacillus sp.) and RZ2MS16 (Burkholderia ambifaria), expressively promoted corn and soybean growth under greenhouse conditions. Compared to the non-inoculated control, increases in corn root dry weight of 247.8 and 136.9% were obtained with RZ2MS9 and RZ2MS16 inoculation, respectively, at 60days after seeding. The dry weights of corn and soybean shoots were significantly higher than those of non-inoculated plants, showing increases of more than 47% for both strains and crops. However, soybean root dry weight did not increased after bacterial inoculation with either strain. The colonization behavior of RZ2MS16 was assessed using GFP-labeling combined with fluorescence microscopy and a cultivation-based approach for quantification. RZ2MS16:gfp was able to colonize the roots and shoots of corn and soybean, revealing an endophytic behavior.