Molecular genotyping analysis suggested high clonality and simple marker loci in Puccinia striiformis f. sp. tritici population in Uzbekistan, Central Asian region.

Puccinia striiformis f. sp. tritici (Pst) is a destructive pathogen that causes wheat stripe rust worldwide. Understanding the population structure and dynamic of pathogen spread is critical to fight against this disease. Limited information is available for the population genetic structure of Pst in Uzbekistan, Central Asia. In this study, we carried out surveillance from 9 different regions (Andijan, Fergana, Jizzakh, Kashkadarya, Namangan, Samarkand, Sirdaryo, Surkhandarya and Tashkent) of Uzbekistan to fill this gap. A total of 255 isolates were collected, which were genotyped using 17 polymorphic simple sequence repeats (SSR) markers. The DAPC analysis results showed no population subdivision in these sample-collected regions except Surkhandarya. Multilocus genotype (MLG) analysis, FST, and Nei's genetic distance results indicated a clonal population (rBarD ≤ 0.12) and merely three MLGs accounting for 70% of the overall population. MLG-34 was predominant in all Uzbekistan regions, followed by MLG-36 and MLG-42. Low genotypic diversity was observed in Andijan, Fergana, Jizzakh, Kashkadarya, Namangan, Sirdaryo, and Tashkent (0.56 to 0.76), compared with Samarkand (0.82) and Surkhandarya (0.97). No virulence against Yr5, Yr15, YrSp, and Yr26 was found, while resistant was overcome against Yr1, Yr2, Yr6, Yr9, Yr17, and Yr44 genes (Virulence frequency =≥75%). Comparative study results of Uzbekistan with previous Himalayan population were showed divergence from China and Pakistan populations. Further studies need to be conducted in a worldwide context to understand migration patterns; for that purpose, collaborative work is essential due to the Pst long-distance migration capability.

Endophytic Bacteria Associated with Medicinal Plant Vernonia anthelmintica: Diversity and Characterization.

Increasing evidence shows that endophytic bacteria living inside plant tissue may possess similar biological activity and produce similar metabolites to their hosts. This study aimed to determine the diversity of endophytic bacteria associated with Vernonia anthelmintica and to evaluate their biological activity. The bacteria were isolated from the plant tissue using culture-dependent techniques. Comparison of the 16S rRNA gene sequences of endophytic bacteria isolated from V. anthelmintica showed that isolates belong to the species Micrococcus endophyticus VERA1, Bacillus megaterium VERA2, Pseudomonas chlororaphis VERA3, P. kilonensis VERA4, Stenotrophomonas pavanii VERA5, B. endophyticus VERA6, S. maltophilia VERA7, Pantoea ananatis VERA8, B. atrophaeus VERA9 and M. flavus VERA10. Activity studies showed that the endophytic bacteria share several similar biological properties with their host plant including antimicrobial, anti-vitiligo and antidiabetic activities. These findings indicate that plant phytochemical compounds and activity play an important role in the physiological properties of their endophytes.

Integration of molecular tools in microbial phosphate solubilization research in agriculture perspective.

Phosphorus (P) is the second most crucial nutrient for plant growth after nitrogen. However, its highly reactive nature causes formation of insoluble derivatives and limits uptake by the plant roots. The wide spread applications of P based chemical fertilizers cause detrimental effects on soil fertility, agricultural product quality and environment. In this regard, phosphate-solubilizing microorganisms (PSMs) stand out as the most remarkable and promising tools for the development of safer and sustainable technologies. As a result of this, many bacterial and fungal species with significant phosphate-solubilizing activity have been discovered by using the conventional screening methods. However, the growing need for the discovery of new strains of PSMs necessitates the replacement or support to the time-consuming conventional methods with techniques that are more sensitive, reliable, reproducible and less time consuming. In this context, molecular tools and techniques provide novel approaches for microbial phosphate solubilization research. Hence, in this review information on the molecular approaches for the PSMs research is provided and its importance explained. The review also discusses the genes related to phosphate solubilizing mechanisms and molecular tools for screening these genes.

Croceibacterium gen. nov., with description of Croceibacterium ferulae sp. nov., an endophytic bacterium isolated from Ferula sinkiangensis K. M. Shen and reclassification of Porphyrobacter mercurialis as Croceibacterium mercuriale comb. nov.

A novel endophytic bacterium, designated strain SX2RGS8T, was isolated from the surface-sterilized roots of an endangered medicinal plant (Ferula sinkiangensis K. M. Shen) collected from Xinjiang, north-western PR China. The taxonomic position of the candidate was investigated using a polyphasic approach. Strain SX2RGS8T was found to be aerobic, Gram-stain-negative, oxidase-negative, catalase-positive and axiolitic-shaped. Strain SX2RGS8T grew at 4-45 °C (optimum, 28 °C), pH 4.0-10.0 (pH 7.0) and in the presence of 0-5 % (w/v) NaCl. The polar lipids detected for strain SX2RGS8T were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylinositol, unidentified phosphoglycolipids, an unidentified phospholipid and unidentified lipids. The major respiratory quinone of strain SX2RGS8T was ubiquinone 10 and the major fatty acid was summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The DNA G+C content was determined to be 66.5 mol%. Phylogenetic analyses based on 16S rRNA gene sequences indicated that the isolate belonged to the family Erythrobacteraceae and showed 99.2 % (Porphyrobacter mercurialis), 95.5 % (Porphyrobacter donghaensisi) and 95.4 % (Porphyrobacter colymbi) similarities to its closest relatives. The isolate contained carotenoids, but no bacteriochlorophyll a. On the basis of phenotypic, genotypic and phylogenetic data, strain SX2RGS8T represents a novel species of a novel genus in the family Erythrobacteraceae, for which the name Croceibacterium ferulae gen. nov., sp. nov. is proposed. The type strain is SX2RGS8T (=CGMCC 1.16402T=KCTC 62090T). In addition, Porphyrobacter mercurialis Coil et al. 2016 is proposed to be transferred to this new genus as Croceibacterium mercuriale comb. nov.

Ochrobactrum endophyticum sp. nov., isolated from roots of Glycyrrhiza uralensis.

A novel Gram-staining negative, motile, rod-shaped and aerobic bacterial strain, designated EGI 60010(T), was isolated from healthy roots of Glycyrrhiza uralensis F. collected from Yili County, Xinjiang Province, North-West China. The 16S rRNA gene sequence of strain EGI 60010(T) showed 97.2 % sequence similarities with Ochrobactrum anthropi ATCC 49188(T) and Ochrobactrum cytisi ESC1(T), and 97.1 % with Ochrobactrum lupini LUP21(T). The phylogenetic analysis based on 16S rRNA gene sequences showed that the new isolate clustered with members of the genera Ochrobactrum, and formed a distinct clade in the neighbour-joining tree. Q-10 was identified as the respiratory quinone for strain EGI 60010(T). The major fatty acids were summed feature 8 (C18:1 ω6c and/or C18:1 ω7c), C19:0 cyclo ω8c, summed feature 4 (C17:1 iso I/anteiso B) and C16:0. The polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, phosphatidylglycerol and phosphatidylcholine. The DNA G+C content of strain EGI 60010(T) was determined to be 60.4 mol%. The genomic DNA relatedness values determined between strain EGI 60010(T) and the closely related strains O. anthropi JCM 21032(T), O. cytisi CCTCC AB2014258(T) and O. lupini NBRC 102587(T) were 50.3, 50.0 and 41.6 %, respectively. Based on the results of the molecular studies supported by its differentiating phenotypic characteristics, strain EGI 60010(T) was considered to represent a novel species within the genus Ochrobactrum, for which the name Ochrobactrum endophyticum sp. nov., is proposed. The type strain is EGI 60010(T) (=CGMCC 1.15082(T) = KCTC 42485(T) = DSM 29930(T)).

A synergistic interaction between salt-tolerant Pseudomonas and Mesorhizobium strains improves growth and symbiotic performance of liquorice (Glycyrrhiza uralensis Fish.) under salt stress.

Chinese liquorice (Glycyrrhiza uralensis Fish.) is a salt-tolerant medicinal legume that could be utilized for bioremediation of salt-affected soils. We studied whether co-inoculation of the symbiotic Mesorhizobium sp. strain NWXJ19 or NWXJ31 with the plant growth-promoting Pseudomonas extremorientalis TSAU20 could restore growth, nodulation, and shoot/root nitrogen contents of salt-stressed G. uralensis, which was grown in potting soil and irrigated with 0, 50, and 75 mM NaCl solutions under greenhouse conditions. Irrigation with NaCl solutions clearly retarded the growth of uninoculated liquorice, and the higher the NaCl concentration (75 and 100 mM NaCl), the more adverse is the effect. The two Mesorhizobium strains, added either alone or in combination with P. extremorientalis TSAU20, responded differently to the salt levels used. The strain NWXJ19 was a good symbiont for plants irrigated with 50 mM NaCl, whereas the strain NWXJ31 was more efficient for plants irrigated with water or 75 mM NaCl solution. P. extremorientalis TSAU20 combined with single Mesorhizobium strains alleviated the salt stress of liquorice plants and improved yield and nodule numbers significantly in comparison with single-strain-inoculated liquorice. Both salt stress and inoculation raised the nitrogen content of shoots and roots. The nitrogen contents were at their highest, i.e., 30 and 35 % greater compared to non-stressed uninoculated plants, when plants were inoculated with P. extremorientalis TSAU20 and Mesorhizobium sp. NWXJ31 as well as irrigated with 75 mM NaCl solution. From this study, we conclude that dual inoculation with plant growth-promoting rhizobacteria could be a new approach to improve the tolerance of G. uralensis to salt stress, thereby improving its suitability for the remediation of saline lands.

Plant beneficial traits of endophytic bacteria associated with fennel (Foeniculum vulgare Mill.).

In this study, we used 16S rRNA gene sequence analysis to describe the diversity of cultivable endophytic bacteria associated with fennel (Foeniculum vulgare Mill.) and determined their plant-beneficial traits. The bacterial isolates from the roots of fennel belonged to four phyla: Firmicutes (BRN1 and BRN3), Proteobacteria (BRN5, BRN6, and BRN7), Gammaproteobacteria (BRN2), and Actinobacteria (BRN4). The bacterial isolates from the shoot of fennel represented the phyla Proteobacteria (BSN1, BSN2, BSN3, BSN5, BSN6, BSN7, and BSN8), Firmicutes (BSN4, BRN1, and BRN3), and Actinobacteria (BRN4). The bacterial species Bacillus megaterium, Bacillus aryabhattai, and Brevibacterium frigoritolerans were found both in the roots and shoots of fennel. The bacterial isolates were found to produce siderophores, HCN, and indole-3-acetic acid (IAA), as well as hydrolytic enzymes such as chitinase, protease, glucanase, and lipase. Seven bacterial isolates showed antagonistic activity against Fusarium culmorum, Fusarium solani, and Rhizoctonia. solani. Our findings show that medicinal plants with antibacterial activity may serve as a source for the selection of microorganisms that exhibit antagonistic activity against plant fungal infections and may be considered as a viable option for the management of fungal diseases. They can also serve as an active part of biopreparation, improving plant growth.

Shared governance in the plant holobiont and implications for one health.

The holobiont Holobiont theory is more than 80 years old, while the importance of microbial communities for plant holobionts was already identified by Lorenz Hiltner more than a century ago. Both concepts are strongly supported by results from the new field of microbiome research. Here, we present ecological and genetic features of the plant holobiont that underpin principles of a shared governance between hosts and microbes and summarize the relevance of plant holobionts in the context of global change. Moreover, we uncover knowledge gaps that arise when integrating plant holobionts in the broader perspective of the holobiome as well as one and planetary health concepts. Action is needed to consider interacting holobionts at the holobiome scale, for prediction and control of microbiome function to improve human and environmental health outcomes.

Antimicrobial Action Mechanisms of Natural Compounds Isolated from Endophytic Microorganisms.

Infectious diseases are a significant challenge to global healthcare, especially in the face of increasing antibiotic resistance. This urgent issue requires the continuous exploration and development of new antimicrobial drugs. In this regard, the secondary metabolites derived from endophytic microorganisms stand out as promising sources for finding antimicrobials. Endophytic microorganisms, residing within the internal tissues of plants, have demonstrated the capacity to produce diverse bioactive compounds with substantial pharmacological potential. Therefore, numerous new antimicrobial compounds have been isolated from endophytes, particularly from endophytic fungi and actinomycetes. However, only a limited number of these compounds have been subjected to comprehensive studies regarding their mechanisms of action against bacterial cells. Furthermore, the investigation of their effects on antibiotic-resistant bacteria and the identification of biosynthetic gene clusters responsible for synthesizing these secondary metabolites have been conducted for only a subset of these promising compounds. Through a comprehensive analysis of current research findings, this review describes the mechanisms of action of antimicrobial drugs and secondary metabolites isolated from endophytes, antibacterial activities of the natural compounds derived from endophytes against antibiotic-resistant bacteria, and biosynthetic gene clusters of endophytic fungi responsible for the synthesis of bioactive secondary metabolites.

Viral Community Structure and Potential Functions in the Dried-Out Aral Sea Basin Change along a Desiccation Gradient.

The dried-out Aral Sea basin represents an extreme environment due to a man-made ecological disaster. Studies conducted in this unique environment revealed high levels of pollution and a specifically adapted microbiota; however, viral populations remained entirely unexplored. By employing an in-depth analysis based on the sequencing of metagenomic DNA recovered from rhizosphere samples of Suaeda acuminata (C. A. Mey.) Moq. along a desiccation gradient of 5, 10, and 40 years, we detected a diverse viral community comprising 674 viral populations (viral operational taxonomic units [vOTUs]) dominated by Caudovirales. Targeted analyses highlighted that viral populations in this habitat are subjected to certain dynamics that are driven mainly by the gradient of desiccation, the corresponding salinity, and the rhizosphere bacterial populations. In silico predictions linked the viruses to dominant prokaryotic taxa in the Aral Sea basin, such as Gammaproteobacteria, Actinomycetia, and Bacilli. The lysogenic lifestyle was predicted to be predominant in areas that dried out 5 years ago, representing the early revegetation phase. Metabolic prediction of viral auxiliary metabolic genes (AMGs) suggests that viruses may play a role in the biogeochemical cycles, stress resilience, and competitiveness of their hosts due to the presence of genes that are involved in biofilm formation. Overall, our study provides important insights into viral ecology in an extreme environment and expands our knowledge related to virus occurrence in terrestrial systems. IMPORTANCE Environmental viruses have added a wealth of knowledge to ecological studies with the emergence of metagenomic technology and approaches. They are also becoming recognized as important genetic repositories that underpin the functioning of terrestrial ecosystems but have remain moslty unexplored. Using shotgun metagenome sequencing and bioinformatic tools, we found that the viral community structure was affected during natural revegetation in the dried-up Aral Sea area, a model habitat for investigating natural ecological restoration but still understudied. In this study, we highlight the importance of viruses, elements that are overlooked, for their potential contribution to terrestrial ecosystems, i.e., nutrient cycles, stress resilience, and host competitiveness, during natural revegetation.

Antimicrobial and Cytotoxic Activities of the Secondary Metabolites of Endophytic Fungi Isolated from the Medicinal Plant Hyssopus officinalis.

According to the World Health Organization, it is estimated that by 2050, drug-resistant infections could cause up to 10 million deaths annually. Therefore, finding a new generation of antibiotics is crucial. Natural compounds from endophytic fungi are considered a potential source of new-generation antibiotics. The antimicrobial and cytotoxic effects of ethyl acetate extracts of nine endophytic fungal isolates obtained from Hyssopus officinalis were investigated for bioassay-guided isolation of the natural compounds. An extract of isolate VII showed the highest antimicrobial activities against Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus (30.12 ± 0.20 mm and 35.21 ± 0.20 mm) and Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa (30.41 ± 0.23 mm and 25.12 ± 0.25 mm) among the tested extracts of isolates. Molecular identification of isolate VII confirmed it as Chaetomium elatum based on sequencing of its ITS genes, and it was discovered that this was the first time C. elatum had been isolated from H. officinalis. This isolate was cultured at a large scale for the isolation and identification of the active compound. Penicillic acid was isolated for the first time from C. elatum and its chemical structure was established by NMR spectroscopy. The penicillic acid showed strong antibacterial activities against Bacillus subtilis and Staphylococcus aureus with 20.68 mm and 25.51 mm inhibition zones, respectively. In addition, MIC and MBC values and antibiofilm activities of penicillic acid were determined. It was found that penicillic acid reduced the level of biofilms in proportion to antibacterial activity.

The potential of biochar as a microbial carrier for agricultural and environmental applications.

Biochar can be an effective carrier for microbial inoculants because of its favourable properties promoting microbial life. In this review, we assess the effectiveness of biochar as a microbial carrier for agricultural and environmental applications. Biochar is enriched with organic carbon, contains nitrogen, phosphorus, and potassium as nutrients, and has a high porosity and moisture-holding capacity. The large number of active hydroxyl, carboxyl, sulfonic acid group, amino, imino, and acylamino hydroxyl and carboxyl functional groups are effective for microbial cell adhesion and proliferation. The use of biochar as a carrier of microbial inoculum has been shown to enhance the persistence, survival and colonization of inoculated microbes in soil and plant roots, which play a crucial role in soil biochemical processes, nutrient and carbon cycling, and soil contamination remediation. Moreover, biochar-based microbial inoculants including probiotics effectively promote plant growth and remediate soil contaminated with organic pollutants. These findings suggest that biochar can serve as a promising substitute for non-renewable substrates, such as peat, to formulate and deliver microbial inoculants. The future research directions in relation to improving the carrier material performance and expanding the potential applications of this emerging biochar-based microbial immobilization technology have been proposed.

A Novel Bacillus safensis-Based Formulation along with Mycorrhiza Inoculation for Controlling Alternaria alternata and Simultaneously Improving Growth, Nutrient Uptake, and Steviol Glycosides in Stevia rebaudiana under Field Conditions.

The excess use of chemicals by farmers in the agroecosystems degrades soil quality, disturbs soil ecology, and increases soil salinity and health hazards in humans. Stevia rebaudiana is an important medicinal and aromatic crop whose leaves contain steviol glycosides (SGs). The Bacillus safensis NAIMCC-B-02323 strain STJP from the rhizosphere of S. rebaudiana producing salicylic acid (16.80 µg/mL), chitinase (75.58 U/mL), ß-1,3-glucanase (220.36 U/mL), and cellulase (170 U/mL) was taken as a plant growth-promoting rhizobacteria (PGPR). The cell-free supernatant (CFS) from strain STJP showed significant biocontrol activity against Alternaria alternata (80%), suggesting the protective role of extracellular metabolite(s) against phytopathogens. Paneer whey-based bioformulation (P-WBF) was developed to exploit B. safensis STJP to enhance the growth, nutrient uptake, soil properties, stevioside content, and SGs biosynthesis in S. rebaudiana under an A. alternata-infested field. The combined treatment of P-WBF and mycorrhiza (Glomus fasciculatum ABTEC) significantly enhanced plant growth parameters after 90 days, in comparison with control. The symbiotic action (P-WBF and mycorrhiza) displayed much better results in terms of chlorophyll a and b (improved by 132.85% and 39.80%, respectively), protein (by 278.75%), flavonoid (by 86.99%), carbohydrate (by 103.84%), antioxidant (by 75.11%), and stevioside (by 120.62%) contents in plants as compared to the untreated set. Further, the augmentation of potassium (by 132.39%), phosphorous (by 94.22%), and zinc (by 111.11%) uptake in plant tissues and soil was also observed by the application of P-WBF and mycorrhiza. The expression of UGT74G1 and UGT85C2 genes related to SG biosynthesis was upregulated (2.7- and 3.2-fold, respectively) in plants treated with P-WBF and mycorrhiza as further confirmed by the accumulation of SGs. The results suggest that the application of P-WBF and mycorrhiza not only provides an ecofriendly and sustainable solution to improve stevioside content in S. rebaudiana by a nutrient-linked mechanism but also paves the way to enhanced production of stevioside.

The diversity of bacterial endophytes from Iris pseudacorus L. and their plant beneficial traits.

This study reports the diversity of cultivable endophytic bacteria associated with yellow iris (Iris pseudacorus L.) by using 16S rRNA gene analysis and their plant beneficial traits. The 16S rRNA sequence similarities of endophytic bacteria isolated from the leaves and roots of yellow iris showed that the isolates belonged to the genera Staphylococcus, Streptomyces, Variovorax, Pantoea, Paenibacillus, Bacillus, Janthinobacterium, Enterobacter, Brevibacterium, Agrobacterium, Rhizobium, Xanthomonas translucens, and Pseudomonas. The endophytic bacteria Pseudomonas gessardii HRT18, Brevibacterium frigoritolerans HRT8, Streptomyces atratus HRT13, and Bacillus toyonensis HST13 exhibited antimicrobial activity against five plant pathogenic fungi Fusarium, Rhizoctonia, Botrytis, Pythium, and Alternaria. They also demonstrated the capability to produce chitinase, protease, glucanase, lipase, HCN, and indole-3-acetic acid (IAA). Thirteen isolates (46%) produced IAA, and the most active IAA producers were Bacillus cereus, Agrobacterium tumefaciens, Agrobacterium vitis, Bacillus megaterium, and Bacillus aryabhattai. The IAA producing bacterial isolates stimulated root and shoot growth of garden cress. Our findings suggest that medicinal plants could be a promising source for isolating plant-beneficial bacteria that can be used to enhance the growth and protect plants against soil-borne pathogens.

Function-Based Rhizosphere Assembly along a Gradient of Desiccation in the Former Aral Sea.

The desiccation of the Aral Sea represents one of the largest human-made environmental regional disasters. The salt- and toxin-enriched dried-out basin provides a natural laboratory for studying ecosystem functioning and rhizosphere assembly under extreme anthropogenic conditions. Here, we investigated the prokaryotic rhizosphere communities of the native pioneer plant Suaeda acuminata (C.A.Mey.) Moq. in comparison to bulk soil across a gradient of desiccation (5, 10, and 40 years) by metagenome and amplicon sequencing combined with quantitative PCR (qPCR) analyses. The rhizosphere effect was evident due to significantly higher bacterial abundances but less diversity in the rhizosphere compared to bulk soil. Interestingly, in the highest salinity (5 years of desiccation), rhizosphere functions were mainly provided by archaeal communities. Along the desiccation gradient, we observed a significant change in the rhizosphere microbiota, which was reflected by (i) a decreasing archaeon-bacterium ratio, (ii) replacement of halophilic archaea by specific plant-associated bacteria, i.e., Alphaproteobacteria and Actinobacteria, and (iii) an adaptation of specific, potentially plant-beneficial biosynthetic pathways. In general, both bacteria and archaea were found to be involved in carbon cycling and fixation, as well as methane and nitrogen metabolism. Analysis of metagenome-assembled genomes (MAGs) showed specific signatures for production of osmoprotectants, assimilatory nitrate reduction, and transport system induction. Our results provide evidence that rhizosphere assembly by cofiltering specific taxa with distinct traits is a mechanism which allows plants to thrive under extreme conditions. Overall, our findings highlight a function-based rhizosphere assembly, the importance of plant-microbe interactions in salinated soils, and their exploitation potential for ecosystem restoration approaches. IMPORTANCE The desertification of the Aral Sea basin in Uzbekistan and Kazakhstan represents one of the most serious anthropogenic environmental disasters of the last century. Since the 1960s, the world's fourth-largest inland body of water has been constantly shrinking, which has resulted in an extreme increase of salinity accompanied by accumulation of many hazardous and carcinogenic substances, as well as heavy metals, in the dried-out basin. Here, we investigated bacterial and archaeal communities in the rhizosphere of pioneer plants by combining classic molecular methods with amplicon sequencing as well as metagenomics for functional insights. By implementing a desiccation gradient, we observed (i) remarkable differences in the archaeon-bacterium ratio of plant rhizosphere samples, (ii) replacement of archaeal indicator taxa during succession, and (iii) the presence of specific, potentially plant-beneficial biosynthetic pathways in archaea present during the early stages. In addition, our results provide hitherto-undescribed insights into the functional redundancy between plant-associated archaea and bacteria.

The Integrated Effect of Microbial Inoculants and Biochar Types on Soil Biological Properties, and Plant Growth of Lettuce (Lactuca sativa L.).

Numerous reports confirm the positive effect of biochar application on soil properties and plant development. However, the interaction between root-associated beneficial microbes and different types of biochar is not well understood. The objective of this study was to evaluate the plant growth of lettuce after the application of three types of biochar in loamy, sandy soil individually and in combination with plant-beneficial microbes. Furthermore, total microbial activity in rhizosphere soil of lettuce was measured by means of fluorescein diacetate (FDA) hydrolase and enzyme activities linked to carbon, nitrogen, and phosphorus cycling. We used three types of biochar: (i) pyrolysis char from cherry wood (CWBC), (ii) pyrolysis char from wood (WBC), and (iii) pyrolysis char from maize (MBC) at 2% concentration. Our results showed that pyrolysis biochars positively affected plant interaction with microbial inoculants. Plant dry biomass grown on soil amended with MBC in combination with Klebsiella sp. BS13 and Klebsiella sp. BS13 + Talaromyces purpureogenus BS16aPP inoculants was significantly increased by 5.8% and 18%, respectively, compared to the control plants. Comprehensively, interaction analysis showed that the biochar effect on soil enzyme activities involved in N and P cycling depends on the type of microbial inoculant. Microbial strains exhibited plant growth-promoting traits, including the production of indole 3-acetic-acid and hydrogen cyanide and phosphate-solubilizing ability. The effect of microbial inoculant also depends on the biochar type. In summary, these findings provide new insights into the understanding of the interactions between biochar and microbial inoculants, which may affect lettuce growth and development.

The Metabolic Potential of Endophytic Actinobacteria Associated with Medicinal Plant Thymus roseus as a Plant-Growth Stimulator.

Bio-fertilizer practice considers not only economical but also environmentally friendly, sustainable agriculture. Endophytes can play important beneficiary roles in plant development, directly, indirectly, or synergistically. In this study, the majority of our endophytic actinobacteria were able to possess direct plant growth-promoting (PGP) traits, including auxin (88%), ammonia (96%), siderophore production (94%), and phosphate solubilization (24%), along with cell-wall degrading enzymes such as protease (75%), cellulase (81%), lipase (81%), and chitinase (18%). About 45% of tested strains have an inhibitory effect on the phytopathogen Fusarium oxysporum, followed by 26% for Verticillium dahlia. Overall, our results showed that strains XIEG63 and XIEG55 were the potent strains with various PGP traits that caused a higher significant increase (p ≤ 0.05) in length and biomass in the aerial part and roots of tomato and cotton, compared to the uninoculated plants. Our data showed that the greatest inhibition percentages of two phytopathogens were achieved due to treatment with strains XIEG05, XIEG07, XIEG45, and XIEG51. The GC-MS analysis showed that most of the compounds were mainly alkanes, fatty acid esters, phenols, alkenes, and aromatic chemicals and have been reported to have antifungal activity. Our investigation emphasizes that endophytic actinobacteria associated with medicinal plants might help reduce the use of chemical fertilization and potentially lead to increased agricultural productivity and sustainability.

Diversity and biological activity of culturable endophytic bacteria associated with marigold (Calendula officinalis L.).

Endophytes colonizing plant tissue play an essential role in plant growth, development, stress tolerance and plant protection from soil-borne diseases. In this study, we report the diversity of cultivable endophytic bacteria associated with marigold (Calendula officinalis L.) by using 16S rRNA gene analysis and their plant beneficial properties. A total of 42 bacterial isolates were obtained from plant tissues of marigold. They belonged to the genera Pantoea, Enterobacter, Pseudomonas, Achromobacter, Xanthomonas, Rathayibacter, Agrobacterium, Pseudoxanthomonas, and Beijerinckia. Among the bacterial strains, P. kilonensis FRT12, and P. rhizosphaerae FST5 showed moderate or vigorous inhibition against three tested plant pathogenic fungi, F. culmorum, F. solani and R. solani. They also demonstrated the capability to produce hydrolytic enzymes and indole-3-acetic acid (IAA). Five out of 16 isolates significantly stimulated shoot and root growth of marigold in a pot experiment. The present study reveals that more than half of the bacterial isolates associated with marigold (C. officinalis L.) provided antifungal activity against one or more plant pathogenic fungi. Our findings suggest that medicinal plants with antimicrobial activity could be a source for selecting microbes with antagonistic activity against fungal plant pathogens or with plant growth stimulating potential. These isolates might be considered as promising candidates for the improvement of plant health.

Towards policies that capture the expected value of biomolecular diversity for drug discovery, human health, and well-being.

This paper aims to help policy makers with a characterization of the intrinsic value of biodiversity and its role as a critical foundation for sustainable development, human health, and well-being. Our objective is to highlight the urgent need to overcome economic, disciplinary, national, cultural, and regional barriers, in order to work out innovative measures to create a sustainable future and prevent the mutual extinction of humans and other species. We emphasize the pervasive neglect paid to the cross-dependency of planetary health, the health of individual human beings and other species. It is critical that social and natural sciences are taken into account as key contributors to forming policies related to biodiversity, conservation, and health management. We are reaching the target date of Nagoya treaty signatories to have accomplished measures to prevent biodiversity loss, providing a unique opportunity for policy makers to make necessary adjustments and refocus targets for the next decade. We propose recommendations for policy makers to explore novel avenues to halt the accelerated global loss of biodiversity. Beyond the critical ecological functions biodiversity performs, its enormous untapped the repertoire of natural molecular diversity is needed for solving accelerating global healthcare challenges.

Diversity and Plant Growth-Promoting Ability of Endophytic, Halotolerant Bacteria Associated with Tetragonia tetragonioides (Pall.) Kuntze.

The diversity of salt-tolerant cultivable endophytic bacteria associated with the halophyte New Zealand spinach (Tetragonia tetragonioides (Pall.) Kuntze) was studied, and their plant beneficial properties were evaluated. The bacteria isolated from leaves and roots belonged to Agrobacterium, Stenotrophomonas, Bacillus, Brevibacterium, Pseudomonas, Streptomyces, Pseudarthrobacter, Raoultella, Curtobacterium, and Pantoea. Isolates exhibited plant growth-promoting traits, including the production of a phytohormone (indole 3-acetic-acid), cell wall degrading enzymes, and hydrogen cyanide production. Furthermore, antifungal activity against the plant pathogenic fungi Fusarium solani, F. oxysporum, and Verticillium dahliae was detected. Ten out of twenty bacterial isolates were able to synthesize ACC deaminase, which plays a vital role in decreasing ethylene levels in plants. Regardless of the origin of isolated bacteria, root or leaf tissue, they stimulated plant root and shoot growth under 200 mM NaCl conditions. Our study suggests that halophytes such as New Zealand spinach are a promising source for isolating halotolerant plant-beneficial bacteria, which can be considered as potentially efficient biofertilizers in the bioremediation of salt-affected soils.