It is claimed that one g of soil holds ten billion bacteria representing thousands of distinct species. These bacteria play key roles in the regulation of terrestrial carbon dynamics, nutrient ...cycles, and plant productivity. Despite the overwhelming diversity of bacteria, most bacterial species remain largely unknown. Here, we used an oligotrophic medium to isolate novel soil bacteria for positive interaction with soybean. Strictly 22 species of bacteria from the soybean rhizosphere were selected. These isolates encompass ten genera (
,
,
,
,
,
,
,
,
, and
) and have potential as novel species. Furthermore, the novel bacterial species exhibited plant growth-promoting traits in vitro and enhanced soybean growth under drought stress in a greenhouse experiment. We also reported the draft genome sequences of
sp. strain SOY2 and
sp. strain SOY23. Along with our analysis of 169 publicly available genomes for the genera reported here, we demonstrated that these bacteria have a repertoire of genes encoding plant growth-promoting proteins and secondary metabolite biosynthetic gene clusters that directly affect plant growth. Taken together, our findings allow the identification novel soil bacteria, paving the way for their application in crop production.
The genus Tulasnella often forms mycorrhizas with orchids and has worldwide distribution. Species of this genus are associated with a wide range of orchids, including endangered hosts. Initially, ...species identification relied mostly on morphological features and few cultures were preserved for later phylogenetic comparisons. In this study, a total of 50 Tulasnella isolates were collected from their natural sites in Minas Gerais, Brazil, cultured, and subjected to a phylogenetic analysis based on alignments of sequences of the internal transcribed spacer (ITS) of the nuclear ribosomal DNA. Our results, based on phylogeny, integrated with nucleotide divergence and morphology, revealed the diversity of isolated Tulasnella species, which included four new species, namely, Tulasnella brigadeiroensis, Tulasnella hadrolaeliae, Tulasnella orchidis and Tulasnella zygopetali. The conservation of these species is important due to their association with endangered orchid hosts and endemic features in the Brazilian Atlantic Forest.
Agroecology aims to maintain ecosystem services by minimizing the impact of agriculture and promoting the use of biological potential. Arbuscular mycorrhizal fungi (AMF) are elements which are key to ...improving crop productivity and soil quality. It is pertinent to understand how agricultural management in the tropics affects the AMF spatio-temporal community composition, especially in crops of global importance, such as coffee (Coffea arabica L.). Soil and root samples were collected from three localities under three management systems (agroecological, conventional and forest fragment), during the phenological stages of coffee (flowering, grain filling, harvesting). Spores were extracted for morphological identification and molecular community analysis by PCR-DGGE. Dendrograms were prepared and the bands were sequenced and analyzed by bioinformatics. No differences were observed in the richness of morphospecies between management systems, localities and period, but little is known about tropical species. Molecular analysis showed that the agroecological management system was similar to natural forest and with a higher diversity indices than conventional management. Locality and period of sample affect AMF community composition. It is necessary to associate classical taxonomic evaluations with molecular biological techniques because different approaches can lead to different outcomes. This study contributes to the understanding of the impact of agriculture management systems on AMF and provides evidence that agroecology is a management system applicable to sustainable coffee production.
•Microorganisms act directly on coffee beverage quality.•Induced fermentation increases the sensory classification of coffee beverage.•Total sensory score for fermented coffee was higher than ...unfermented coffee.•Total score was higher in the washed method than in dry fermentation at 108 and 216 h.•The formation of groups in dry fermentation was mainly due to balance and body.
Microorganisms influence the sensory quality of the coffee beverage through the compounds degradation or release of metabolites that diffuse into the fruit. However, type and duration of fermentation can contribute to the growth and diversity of microorganisms. Thus, the objective of this study was to analyze the microbial and sensory profile of Arabica coffees under different fruit-processing conditions and fermentation by Saccharomyces cerevisiae. Coffee cherries were used in the dry fermentation and washed fermentation at 28°C. Fermentation time ranged from 36 to 288 hours. A panel of sensory attributes was evaluated by 9 Q-graders. Mid-infrared spectra were obtained in the wavenumber range from 4000 to 650 cm−1. Microbial analyses were performed by denaturing gradient gel electrophoresis. Total sensory score for fermented coffee was higher than for unfermented coffee. In 108 and 216 hours of fermentation, the total score was higher in washed fermentation than in dry fermentation, which also shows the influence of post-harvest processing and the removal of husk on the quality of fermented coffee. Balance and body were the sensory attributes that most contributed to group formation in dry fermentation. Thus, induced fermentation increases the sensory classification of coffee beverages with positive effects on chemical and sensory profiles.
Post-harvest processing and microbial fermentation of coffee fruits play an essential role in the metabolites formation that influence the nutritional and sensory quality of the beverage. Thus, the ...objective of this study was to analyze the effect of coffee cherries processing and fermentation conditions on the microbial communities and the chemical and sensory quality of the beverage. Induced fermentation changed in the bacteria and fungi communities (Treatments: T1, T3, and T7).
Klebsiella
sp. inoculation (T1) allowed an increase in richness of bacteria and 81 points in the sensory score over the fermentation time. However, there was a reduction in richness of microbial community in treatments with
Saccharomyces cerevisiae
(T3 and T7)
.
An increase in the indexes of microbial diversity was observed in 72 h in treatment with coffee pulp (T2). In treatment with coffee cherries and spontaneous fermentation (T4) had a higher sensory score than other treatments, indicating a sensory gain from 36 to 72 h. Coffee cherries with superficial disinfection (T5) had a reduction in microbial profile, but did not change the final score of the beverage over the 72 h. In T6 (floaters fruits) was observed an alteration in the fungal community (36–72 h) and the lowest sensory score. The impact of adding water on coffee fermentation was dependent on time (T3 and T7). Furthermore, 5-hydroxymethylfurfural has a positive correlation with the final score of the beverage. Thus, microbial profile and sensory score of beverages are dependent of conditions of processing of coffee fruits and fermentation.
•Sequencing was crucial to identify the bacterial succession during fermentation.•Food safety is a factor important in the microbial fermentations of coffee.•Fermentation at 38 °C promotes more ...shifts in the bacterial composition.•High temperature and time of fermentation favors Lactobacillus sp.•Relative abundance of Lactobacillus is directly correlated with sensory scores.
The diversity and activity of the indigenous microorganisms in coffee are essential for obtaining safe and good-quality coffee. The use of fermentation under carbonic maceration in coffee fruits showed a positive correlation between the bacterial community and sensory score. Thus, the objective of this study was to evaluate the bacterial diversity in coffee cherries during fermentation under carbonic maceration and their correlations with coffee-quality. Next-generation sequencing and Specialty Coffee Association protocol were used in this study. Predominance of Leuconostoc sp. and Lactobacillus sp. during fermentation was observed. Leuconostoc sp. had higher relative abundance in the initial phase of fermentation and at 18 and 28 °C than Lactobacillus sp. Furthermore, the greatest microbial diversity occurred at 38 °C and after 72 h. At this temperature, the relative abundance of Lactobacillus correlated positively with sensorial score. Thus, an increase in temperature and fermentation time favors Lactobacillus spp and coffee sensory quality.
The physical or morphological integrity of the coffee bean during post-harvest processing directly influences the economic value and sensory quality of the coffee beverage. Breakdowns in the outer ...layers of the beans are characteristics observed for the morphological and economic classification of coffee beans during the commercialization of this product. However, physical changes in the inner layers of the beans that are not seen with the naked eye can also influence the sensory quality of the coffee. Therefore, the objective of this study was to relate changes in the physical structure of coffee beans roasted by four different processes (light, medium, dark, and baked) with the sensory attributes of the beverage. The analyses of the physical characteristics of the coffee beans were carried out by X-ray microtomography and the sensory profile was determined using the Specialty Coffee Association of America protocol. The roasting profile with the highest sensory scores showed higher values for total pore space volume and a negative Euler number. However, the roasting profiles that fluctuated between the highest and lowest of scores of the sensory attributes did not present standardized behavior for the connectivity, Euler number, and total pore space volume. Hence, morphological or physical changes in the coffee beans caused by the different types of roasting correlate with changes in the sensorial profile. Furthermore, the sensory discrimination of these coffee beans among the different roast profiles may be observed by the joint analysis of the flavor and fragrance scores.
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