Physiological and Proteomic Analyses of Different Ecotypes of Reed (Phragmites communis) in Adaption to Natural Drought and Salinity

Drought and salinity are the two major abiotic stresses constraining the crop yield worldwide. Both of them trigger cellular dehydration and cause osmotic stress which leads to cytosolic and vacuolar volume reduction. However, whether plants share a similar tolerance mechanism in response to these two stresses under natural conditions has seldom been comparatively reported. There are three different ecotypes of reed within a 5 km2 region in the Badanjilin desert of Northwest China. Taking the typical swamp reed (SR) as a control, we performed a comparative study on the adaption mechanisms of the two terrestrial ecotypes: dune reed (DR) and heavy salt meadow reed (HSMR) by physiological and proteomic approaches coupled with bioinformatic analysis. The results showed that HSMR and DR have evolved C4-like photosynthetic and anatomical characteristics, such as the increased bundle sheath cells (BSCs) and chloroplasts in BSCs, higher density of veins, and lower density and aperture of stomata. In addition, the thylakoid membrane fluidity also plays an important role in their higher drought and salinity tolerance capability. The proteomic results further demonstrated that HSMR and DR facilitated the regulation of proteins associated with photosynthesis and energy metabolism, lipid metabolism, transcription and translation, and stress responses to well-adapt to the drought and salinity conditions. Overall, our results demonstrated that HSMR and DR shaped a similar adaption strategy from the structural and physiological levels to the molecular scale to ensure functionality in a harsh environment.

Genome resource of Ancylobacter pratisalsi E130 T: A novel plant growth-promoting bacterium isolated from the rhizosphere

Ancylobacter pratisalsi sp. nov. strain E130T is a Gram negative, non-motile, aerobic and rod-shaped bacterium, which was recently isolated from the rhizosphere of Plantago winteri Wirtg from a natural salt meadow. This strain was described as novel species in Ancylobacter genus, however information about its complete genome has yet not been reported. In this study, its genome was completely sequenced by PacBio SMRT cell platform, analyzed, and compared with other selected complete genome sequences of Ancylobacter and elucidated its potential plant growth promotion abilities. The genomic analysis revealed that the genome of strain E130T consists of one circular DNA chromosome of 4,618,530 bp with a GC content of 66% and one plasmid of 159,741 bp with a GC content of 64.13%. The entire genome contains 4,322 predicted coding genes, 49 tRNAs and 6 rRNA genes. Genome analysis identified a siderophore natural product biosynthesis cluster, which produces fuscachelin. Knockout of several key genes in this cluster, significantly reduces the plant growth-promotion ability of the strain E130T. Besides plant growth-promotion, the strain E130T can grow well on 5 % NaCl (w/v), conferring this strain as potential bio-resource for successful production of economic crops in alkaline soil.

Spirosoma endbachense sp. nov., isolated from a natural salt meadow

A Gram-stain-negative bacterium, designated I-24T, was isolated from soil of a natural salt meadow. Strain I-24T was aerobic, non-motile, rod-shaped, catalase-positive, oxidase-positive and grew optimally at pH 7 and 25 °C. Comparative 16S rRNA gene analysis indicated that strain I-24T has closest similarities to Spirosoma agri KCTC 52727T (95.9 %) and Spirosoma terrae KCTC 52035T (95.5 %). Strain I-24T contained summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c) and C16 : 1 ω5c as the major fatty acids, the predominant respiratory quinone was menaquinone MK-7, and the major polar lipids were phosphatidylethanolamine as well as an unidentified phosphoaminolipid. The draft genome of strain I-24T consists of 10 326 072 base pairs with 9153 predicted coding sequences and a G+C content of 47.7 mol%. Clear distinctions between strain I-24T and S. agri KCTC 52727T or S. terrae KCTC 52035T were shown in the pairwise average nucleotide identity results with values of 76.71 and 74.01 %, respectively. Moreover, the digital DNA–DNA relatedness values to these strains were 20.8 and 19.0 %. Based on its phenotypic, genotypic and chemotaxonomic characteristics, strain I-24T represents a novel species of the genus Spirosoma , for which the name Spirosoma endbachense sp. nov. is proposed. The type strain is I-24T (DSM 111055T=KCTC 72613T).

Measurement of degradation on under-utilized natural turf

The role of turf serving animal husbandry is significantly declining with the decreasing number of grazing livestock in Hungary. Accordingly, the area of under-utilized or non-utilized turfs is increasing. At the University of Debrecen, Institutes for Agricultural Research and Educational Farm, Karcag Research Institute we studied four types of turf utilization in three repetitions on a salt meadow with Alopecurus pratensis. As a result of the performed examinations, we identified the composition of the flora structure on the investigated area and we measured carbon-dioxide circulation and soil moisture.

A Model for Estimating the Vegetation Cover in the High-Altitude Wetlands of the Andes (HAWA)

The natural salt meadows of Tilopozo in the hyperarid, Atacama Desert of northern Chile, which are located at approximately 2800 m above sea level, are under pressure from industrial activity, and cultivation and grazing by local communities. In this research, the land surface covered by salt meadow vegetation was estimated from normalized difference vegetation indices (NDVI) derived from Landsat Thematic Mapper (TM), Enhanced Thematic Mapper (ETM+) and Operational Land Imager (OLI) data from 1985 to 2016. The vegetated area of the Tilopozo salt meadows decreased by 34 ha over the 32-year period studied. Multiple regression models of the area covered by vegetation and climate data and groundwater depths were derived on an annual basis, as well as for both the dry and wet seasons and had R2 values of 83.0%, 72.8% and 92.4% respectively between the vegetated areas modeled and those estimated from remotely sensed data. These models are potentially useful tools for studies into the conservation of the Tilopozo salt meadows, as they provide relevant information on the state of vegetation and enable changes in vegetation in response to fluctuations in climate parameters and groundwater depths to be predicted.

Hartmannibacter diazotrophicus gen. nov., sp. nov., a phosphate-solubilizing and nitrogen-fixing alphaproteobacterium isolated from the rhizosphere of a natural salt-meadow plant

A phosphate-mobilizing, Gram-negative bacterium was isolated from rhizospheric soil of Plantago winteri from a natural salt meadow as part of an investigation of rhizospheric bacteria from salt-resistant plant species and evaluation of their plant-growth-promoting abilities. Cells were rods, motile, strictly aerobic, oxidase-positive and catalase-negative. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain E19T was distinct from other taxa within the class Alphaproteobacteria . Strain E19T showed less than 93.5 % 16S rRNA gene sequence similarity with members of the genera Rhizobium (≤93.5 %), Labrenzia (≤93.1 %), Stappia (≤93.1 %), Aureimonas (≤93.1 %) and Mesorhizobium (≤93.0 %) and was most closely related to Rhizobium rhizoryzae (93.5 % 16S rRNA gene sequence similarity to the type strain). The sole respiratory quinone was Q-10, and the polar lipids comprised phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, an aminolipid and an unidentified phospholipid. Major fatty acids were C18 : 1ω7c (71.4 %), summed feature 2 (C14 : 0 3-OH and/or iso-C16 : 1; 8.3 %), C20 : 0 (7.9 %) and C16 : 0 (6.1 %). The DNA G+C content of strain E19T was 59.9±0.7 mol%. The capacity for nitrogen fixation was confirmed by the presence of the nifH gene and the acetylene reduction assay. On the basis of the results of our polyphasic taxonomic study, the new isolate represents a novel genus and species, for which the name Hartmannibacter diazotrophicus gen. nov., sp. nov. is proposed. The type strain of Hartmannibacter diazotrophicus is E19T ( = LMG 27460T = KACC 17263T).

Rheinheimera hassiensis sp. nov. and Rheinheimera muenzenbergensis sp. nov., two species from the rhizosphere of Hordeum secalinum

Two motile, Gram-staining-negative, aerobic, rod-shaped bacteria designated strains E48T and E49T were isolated from the rhizosphere of Hordeum secalinum from a natural salt meadow near Münzenberg, Germany. 16S rRNA gene sequence similarity analysis revealed that strains E48T and E49T shared similarities of 97.6 % with Rheinheimera pacifica KMM 1406T and 98.5 % with Rheinheimera nanhaiensis E407-8T, respectively. Major fatty acids of strain E48T were C16 : 0, summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) and C17 : 1ω8c, and of strain E49T were C16 : 0, summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH) and C18 : 1ω7c. The DNA G+C contents were 50.5 mol% (E48T) and 50.0 mol% (E49T). Strains E48T and E49T grew at 4–37 °C (optimum 28 °C) and with 0–6 % NaCl (optimum 0–3 %) and 0–5 % NaCl (optimum 0–3 %), respectively. The potential for nitrogen fixation by strains E48T and E49T was evaluated by molecular techniques and the acetylene reduction assay. The DNA–DNA hybridization, physiological and molecular data demonstrated that strains E48T and E49T represent two novel species of the genus Rheinheimera , and therefore the names Rheinheimera hassiensis sp. nov. (type strain E48T = LMG 27268T = KACC 17070T) and Rheinheimera muenzenbergensis sp. nov. (type strain E49T = LMG 27269T = KACC 17071T) are proposed.

Cellvibrio diazotrophicus sp. nov., a nitrogen-fixing bacteria isolated from the rhizosphere of salt meadow plants and emended description of the genus Cellvibrio

Two Gram-reaction-negative, aerobic, nitrogen-fixing, rod-shaped bacteria, designated strains E20 and E50T, were isolated from the rhizosphere of salt meadow plants Plantago winteri and Hordeum secalinum, respectively, near Münzenberg, Germany. Based on the 16S rRNA gene sequence analysis both strains E20 and E50T are affiliated with the genus Cellvibrio , sharing the highest similarity with Cellvibrio gandavensis LMG 18551T (96.4 %) and (97.1 %), respectively. Strains E20 and E50T were oxidase and catalase-positive, grew at a temperature range between 16 and 37 °C and in the presence of 0–5 % NaCl (w/v). The DNA G+C contents were 52.1 mol% (E20) and 51.6 mol% (E50T). Major fatty acids of strains E20 and E50T were summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH), C16 : 0, C18 : 1ω7c, C12 : 0, C18 : 0 and C12 : 0 3-OH. The DNA–DNA relatedness of the strains to Cellvibrio gandavensis LMG 18551T was 39 % for strain E20 and 58 % for strain E50T. The nitrogen fixation capability of strains E20 and E50T was confirmed by the acetylene reduction assay. On the basis of our polyphasic taxonomic study, strains E20 and E50T represent a novel species of the genus Cellvibrio , for which the name Cellvibrio diazotrophicus is proposed. The type strain of Cellvibrio diazotrophicus is E50T ( = LMG 27267T = KACC 17069T). An emended description of the genus Cellvibrio is proposed based on the capability of fixing nitrogen and growth in presence of up to 5 % NaCl (w/v).