Potassium ameliorates cotton (Gossypium hirsutum L.) fiber length by regulating osmotic and K+ /Na+ homeostasis under salt stress.

Potassium (K) application can alleviate cotton salt stress, but the regulatory mechanisms affecting cotton fiber elongation and ion homeostasis are still unclear. A two-year field experiment was conducted to explore the effects of K on the osmolyte contents (soluble sugar, K+ content, and malate) and related enzyme activities during the fiber elongation of two cotton cultivars with contrasting salt sensitivity (CCRI-79; salt tolerant cultivar, and Simian 3; salt-sensitive cultivar). Three K application treatments (0, 150, and 300 kg K2 O ha-1 ) were applied at three soil salinity levels (low salinity, EC = 1.73 ± 0.05 dS m-1 ; medium salinity, EC = 6.32 ± 0.10 dS m-1 ; high salinity, EC = 10.84 ± 0.24 dS m-1 ). K application improved fiber length and alleviated salt stress by increasing the maximum velocity of fiber elongation (Vmax ). The increase rate of K on fiber length decreased with elevating salt stress, and the increase rate of K on Vmax of CCRI-79 was greater than that of Simian3. K application can increase the enzyme activities (phosphoenolpyruvate carboxylase, PEPC, E.C. 4.1.1.31; pyrophosphatase, PPase, E.C. 3.6.1.1; and plasma membrane H+ -ATPase, PM H+ -ATPase, E.C. 3.6.3.14) as well as the content of osmolytes associated with the enzymes mentioned above. K increased the osmolyte contents under salt stress, and the increase in the K+ content of the fibers was much higher than that of soluble sugar and malate. The results of this study indicated K fertilizer application rates regulate the metabolism of osmolytes in cotton fiber development under salt stress, K+ is more critical to fiber elongation.

Keystone microbes affect the evolution and ecological coexistence of the community via species/strain specificity.

AIM: Microbial communities exhibit different diversity and fluctuations in the ecological functions due to time and environmental migration. Despite a long history of research and a plethora of data, the factors determining the biodiversity and stability of ecosystems is still elusive. METHODS AND RESULTS: Here, the Chinese Xiaoqu fermentation system was used as a template to explore the mechanism in which the species specificity and strain in the initial phase affect the community structure and metabolites in the subsequent micro-ecosystem. The micro-ecosystem has been applied for hundreds of years, and the main metabolic function can be reproduced and traced. CONCLUSIONS: The result proved that Rhizopus spp. is a keystone microbe with a species/strain specificity affecting the trophic interaction niche and function of modules in the complex community through glucose. The fungal community was demonstrated to have a high sealing and stability, while the bacterial community was generally found to change the community structure, physiological function, and interaction relationship, producing strains with connector functions to adapt to fluctuations. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that the taxonomic level of key microbial strains can be changed to affect the evolution of coexistence and functional realisation of the community.

Characterizing the Contribution of Strain Specificity to the Microbiota Structure and Metabolites of Muqu and Fresh High-Temperature Daqu.

In this study, the differences in physicochemical properties, microbial community structure, and metabolic characteristics between various fortified Muqu and their corresponding high-temperature Daqu (HTD) were investigated using multiphase detection methods. The results demonstrated that the physicochemical properties, community structure, dominant bacterial composition, and metabolic components varied significantly among the different types of fortified HTD. The differences between HTDs became more pronounced when fortified HTD was used as Muqu. Compared to HTD, Muqu exhibited a more complex volatile profile, while HTD contained higher levels of characteristic non-volatile components. The cultivable bacteria count in Muqu was significantly higher than that in HTD, while the cultivable fungi count was slightly lower than that in HTD. The fungal profiles in HTD were primarily associated with starch hydrolysis and ethanol synthesis, while bacterial activity was more prominent in Muqu. Additionally, pyrazine synthesis was mainly attributed to fungi in Muqu and bacteria in HTD. Source Tracker analysis indicated that 8.11% of the bacteria and 26.76% of the fungi originated from Muqu. This study provides a theoretical foundation for the controlled production of HTD, contributing to improvements in its quality and consistency.

Reducing soil and leaf shadow interference in UAV imagery for cotton nitrogen monitoring.

Introduction: Individual leaves in the image are partly veiled by other leaves, which create shadows on another leaf. To eliminate the interference of soil and leaf shadows on cotton spectra and create reliable monitoring of cotton nitrogen content, one classification method to unmanned aerial vehicle (UAV) image pixels is proposed. Methods: In this work, green light (550 nm) is divided into 10 levels to limit soil and leaf shadows (LS) on cotton spectrum. How many shadow has an influence on cotton spectra may be determined by the strong correlation between the vegetation index (VI) and leaf nitrogen content (LNC). Several machine learning methods were utilized to predict LNC using less disturbed VI. R-Square (R 2), root mean square error (RMSE), and mean absolute error (MAE) were used to evaluate the performance of the model. Results: (i) after the spectrum were preprocessed by gaussian filter (GF), SG smooth (SG), and combination of GF and SG (GF&SG), the significant relationship between VI and LNC was greatly improved, so the Standard deviation of datasets was also decreased greatly; (ii) the image pixels were classified twice sequentially. Following the first classification, the influence of soil on vegetation index (VI) decreased. Following secondary classification, the influence of soil and LS to VI can be minimized. The relationship between the VI and LNC had improved significantly; (iii) After classifying the image pixels, the VI of 2-3, 2-4, and 2-5 have a stronger relationship with LNC accordingly. Correlation coefficients (r) can reach to 0.5. That optimizes monitoring performance when combined with GF&SG to predict LNC, support vector machine regression (SVMR) has the better performance, R 2, RMSE, and MAE up to 0.86, 1.01, and 0.71, respectively. The UAV image classification technique in this study can minimize the negative effects of soil and LS on cotton spectrum, allowing for efficient and timely predict LNC.

Characterizing the Contribution of Functional Microbiota Cultures in Pit Mud to the Metabolite Profiles of Fermented Grains.

Elevating the flavor profile of strong flavors Baijiu has always been a focal point in the industry, and pit mud (PM) serves as a crucial flavor contributor in the fermentation process of the fermented grains (FG). This study investigated the influence of wheat flour and bran (MC and FC) as PM culture enrichment media on the microbiota and metabolites of FG, aiming to inform strategies for improving strong-flavor Baijiu flavor. Results showed that adding PM cultures to FG significantly altered its properties: FC enhanced starch degradation to 51.46% and elevated reducing sugar content to 1.60%, while MC increased acidity to 2.11 mmol/10 g. PM cultures also elevated FG's ester content, with increases of 0.36 times for MC-FG60d and 1.48 times for FC-FG60d compared to controls, and ethyl hexanoate rising by 0.91 times and 1.39 times, respectively. Microbial analysis revealed that Lactobacillus constituted over 95% of the Abundant bacteria community, with Kroppenstedtia or Bacillus being predominant among Rare bacteria. Abundant fungi included Rasamsonia, Pichia, and Thermomyces, while Rare fungi consisted of Rhizopus and Malassezia. Metagenomic analysis revealed bacterial dominance, primarily consisting of Lactobacillus and Acetilactobacillus (98.80-99.40%), with metabolic function predictions highlighting genes related to metabolism, especially in MC-FG60d. Predictions from PICRUSt2 suggested control over starch, cellulose degradation, and the TCA cycle by fungal subgroups, while Abundant fungi and bacteria regulated ethanol and lactic acid production. This study highlights the importance of PM cultures in the fermentation process of FG, which is significant for brewing high-quality, strong-flavor Baijiu.

Mechanism of Enhancing Pyrazines in Daqu via Inoculating Bacillus licheniformis with Strains Specificity.

Despite the importance of pyrazines in Baijiu flavor, inoculating functional strains to increase the contents of pyrazine in Daqu and how those interact with endogenic communities is not well characterized. The effects of inoculating Bacillus licheniformis with similar metabolic capacity on pyrazine and community structure were assessed in the Daqu complex system and compared with traditional Daqu. The fortification strategy increased the volatile metabolite content of Daqu by 52.40% and the pyrazine content by 655.99%. Meanwhile, results revealed that the pyrazine content in Daqu inoculated isolate J-49 was 2.35-7.41 times higher than isolate J-41. Both isolates have the almost same capability of 2,3-butanediol, a key precursor of pyrazine, in pure cultured systems. Since the membrane fatty acids of isolate J-49 contain unsaturated fatty acids, it enhances the response-ability to withstand complex environmental pressure, resulting in higher pyrazine content. PICRUSt2 suggested that the increase in pyrazine was related to the enzyme expression of nitrogen metabolism significantly increasing, which led to the enrichment of NH4+ and 2,3-butanediol (which increased by 615.89%). These results based on multi-dimensional approaches revealed the effect of functional bacteria enhancement on the attribution of Daqu, laid a methodological foundation regulating the microbial community structure and enhanced the target products by functional strains.

Characterizing the correlation between species/strain-specific starter with community assembly and metabolic regulation in Xiaoqu Pei.

Studying the correlation between microbiome metabolism and flavor of fermented foods has garnered significant attention recently. Understanding the contribution of metabolic regulation and environmental stress to microecosystems is essential for exploring the mechanisms of action of traditional fermented foods. Here, the interaction between microbial communities was investigated using a Xiaoqu fermentation system, processed as "simulative microecosystems," in which starters were composed of Rhizopus-specific species/strains, Meyerozyma guilliermondii, and Bacillus licheniformis. The differences between community succession and metabolites were also explored. The results indicated that Rhizopus species/strain specificity affected starch hydrolyzation, resulting in a remarkable difference in the type and content of organic acids. This further suggested that the differences in nutrient abundance and organic acids influenced the colonization of microorganisms in the fermentation system, thereby influencing the succession of their communities. The fungi in the community predominantly originated from starters, whereas the bacteria were derived from both the environment and starter. Environmentally colonized microbes were the major contributors to the co-occurrence network and were strongly correlated with network. Regional characteristics of fermented foods were closely related to environmental microbes. These results contribute to the understanding of microbial assembly and flavor metabolism in fermented foods and provide strategies for quality regulation.

Effects of mulching film on soil microbial diversity and community of cotton.

Different types of mulching film could variously influence soil properties and plant growth. Yet, surprisingly few studies have investigated the effects of mulching film upon soil microbial diversity and community structure. In this research, two kinds of mulching film, a traditional PE (polyethylene) mulching film and a degradable PBAT ((Poly [butyleneadipate-co-terephthalate])) mulching film, were applied to cotton (Gossypium spp.) plants grown in Xinjiang Province, China. The respective influence of the two mulching films on the cotton's soil microbial (bacteria and fungi) diversity and community were investigated. The results showed that applying the PBAT mulching film could significantly alter the diversity of non-rhizosphere soil fungi when compared to using the PE mulching film. However, neither the PE nor PBAT mulching film had any significant influence on the diversity of soil bacteria and rhizosphere soil fungi. Nevertheless, soil microbial community composition differed under the PBAT mulching film treatment vis-à-vis the PE mulching film treatment. The abundance of Gibellulopsis was higher under the PBAT than PE mulching film treatment. Our study's findings provided an empirical basis for the further application of degradable PBAT mulching film for the sustainable development of cotton crops.

Maize Lodging Resistance with Plastic Film Removal, Increased Planting Density, and Cultivars with Different Maturity Periods.

While plastic film mulching and proper high-density planting are important methods that can improve maize yield, years of accumulated residual film have created soil pollution and degraded soil, and thus has impeded sustainable agriculture development. Here, we compared the stalk and root lodging resistances of three maize cultivars grown at two planting densities both with (FM) and without (NM) plastic film mulch. Our aim was to provide a theoretical basis that may help assure a future of successful no-film planting with increased planting density. The results showed that, compared with FM, the average dry weight per unit length and bending strength of basal internode decreased for all cultivars at both planting densities in the NM treatment. At 9.0 × 104 plants ha-1, the stalk breaking force (SFC) of Xinyu77, KWS9384, and KWS2030 in the NM treatment decreased by 4%, 21%, and 22%, respectively. At 12.0 × 104 plants ha-1, SFC of Xinyu77 and KWS2030 increased by 14% and 1%, respectively, while KWS9384 decreased by 10%. Additionally, the root diameter, length, volume, width, depth, and the vertical root-pulling force of maize decreased. Although the lodging resistance of maize grown without film mulch was lower than that of maize grown with it, those adverse effects can be mitigated by selecting suitable cultivars and by using proper high-density planting and appropriate cultivation measures.

Characterization of the flavor in traditional Pixian Doubanjiang by polyphasic quantitative detection technology.

In the present research, four different samples were investigated by multiple analyzing technology to reveal the common unique flavor and taste of traditional Pixian Doubanjiang (PXDBJ). These samples were manufactured by inheritor according to the intangible skills and ripened for two years in different enterprises. Citric acid, malic acid, Glu and Asp were the dominant non-volatiles, the proportion of both organic acids ranged from 54.78% to 65.61%, while that of both free amino acids ranged from 22.49% to 29.39%. Ethyl palmitate, ethyl laurate, γ-cis-himachalane, (+)-valencene and ß-ionone were identified as typical volatile constituents by three kinds of GC techniques combined with three pretreatment approaches. These results suggested that these five volatiles and the proportion of four non-volatiles could be used as indicators of flavor and taste to discriminate with other types of traditional fermented soy pastes (miso, dajiang, gochujiang, etc), and were also proofed by sensory evaluation. It laid a vital foundation for revealing the contribution of the traditional skill to unique quality of PXDBJ and the correlation between microbial community diversity and their metabolic regulation.

Characterizing Relationship of Microbial Diversity and Metabolite in Sichuan Xiaoqu.

Xiaoqu is a fermentation starter used in the production of Xiaoqu jiu, which is also a traditional Chinese liquor. The quality and microbial community characteristics of Xiaoqu is closely related with the yield and flavor feature of fresh Xiaoqu jiu. The present study aims to explore the mystery behind microbial diversity and volatiles of Xiaoqu through polyphasic detection methods such as the Illumina MiSeq platform and the metabolite analyzing method. Results showed that differences in microbial community diversity among samples were significant. The hydrolytic ability was positively correlated with α- and ß-diversity of bacteria, but negatively correlated with that of fungi. Staphylococcus and Weissella were the dominant bacteria, while Rhizopus and Candida were the dominant fungi. The abundance of bacteria in sample No3 ranged from 33.66 to 91.53%, while sample No4 the abundance of fungi ranged from 58.51 to 48.72%. The difference of microbial community diversity resulted in a discrepancy of volatile profiles and interaction relationship among the genus. Twenty-four dominant bacteria and seven dominant fungi were correlated with 20 different volatiles. This study provides a scientific perspective of the uniformity and stability of Xiaoqu jiu and might aid in controlling its manufacturing process.

Correlation between volatile profiles and microbial communities: A metabonomic approach to study Jiang-flavor liquor Daqu.

Microbial community diversity and volatile profiles of 14 Jiang-flavor liquor Daqu (JFLQ) samples were investigated by Illumina MiSeq platform and Head Space-solid Phase Microextraction Gas Chromatograph Mass Spectrometer (HS-SPME-GC-MS). Correlations between microbial community and volatile profiles of JFLQ were disclosed by redundancy analysis. Results indicated the outstanding high content of nitrogenous and aromatics compounds in Moutai Daqu samples, whereas esters were dominant for the samples from the brewing sites rather than Moutai. Bacillales, Enterobacteriales, and Lactobacillales were the dominant bacteria, while Candida, Trichoderma, Aspergillus, Trichosporon and Thermomyces were predominant in the fungal community. Compared to the randomly dispersed feature of fungi communities, bacterial communities had preferred "shelter": Lactobacillales mainly clustered in the surface of Daqu, whereas Bacillales in the core. Microbial interaction of JFLQ was stronger in the core than in the surface. Bacillales and Lactobacillales were closely positive-related with pyrazines and esters respectively, and Aspergillus was correlated with pyrazines, esters and aromatics. Based on the results, a metabolic map of abundant microorganisms in JFLQ was built up.