Salt-tolerant endophytic bacterium Enterobacter ludwigii B30 enhance bermudagrass growth under salt stress by modulating plant physiology and changing rhizosphere and root bacterial community.

Osmotic and ionic induced salt stress suppresses plant growth. In a previous study, Enterobacter ludwigii B30, isolated from Paspalum vaginatum, improved seed germination, root length, and seedling length of bermudagrass (Cynodon dactylon) under salt stress. In this study, E. ludwigii B30 application improved fresh weight and dry weight, carotenoid and chlorophyll levels, catalase and superoxide dismutase activities, indole acetic acid content and K+ concentration. Without E. ludwigii B30 treatment, bermudagrass under salt stress decreased malondialdehyde and proline content, Y(NO) and Y(NPQ), Na+ concentration, 1-aminocyclopropane-1-carboxylate, and abscisic acid content. After E. ludwigii B30 inoculation, bacterial community richness and diversity in the rhizosphere increased compared with the rhizosphere adjacent to roots under salt stress. Turf quality and carotenoid content were positively correlated with the incidence of the phyla Chloroflexi and Fibrobacteres in rhizosphere soil, and indole acetic acid (IAA) level was positively correlated with the phyla Actinobacteria and Chloroflexi in the roots. Our results suggest that E. ludwigii B30 can improve the ability of bermudagrass to accumulate biomass, adjust osmosis, improve photosynthetic efficiency and selectively absorb ions for reducing salt stress-induced injury, while changing the bacterial community structure of the rhizosphere and bermudagrass roots. They also provide a foundation for understanding how the bermudagrass rhizosphere and root microorganisms respond to endophyte inoculation.

Lanthanum Promotes Bahiagrass (Paspalum notatum) Roots Growth by Improving Root Activity, Photosynthesis and Respiration.

Lanthanum (La), one of the most active rare earth elements, promotes the growth of turfgrass roots. In this study, the mechanisms by which La influences bahiagrass (Paspalum notatum) growth were evaluated by the analyses of root growth, root activity, cell wall polysaccharide content, respiration intensity, ascorbic acid oxidase (AAO) and polyphenol oxidase (PPO) activity, the subcellular distribution of mitochondria, transcription in roots, photosynthetic properties, chlorophyll fluorescence parameters, and chlorophyll content. The application of 0.3 mM La3+ increased root activity, respiration intensity, AAO activity, and the number of mitochondria in the mature cells of bahiagrass roots. La could significantly improve the net photosynthetic rate, transpiration rate, and chlorophyll fluorescence of bahiagrass. Differentially expressed genes identified by high-throughput transcriptome sequencing were enriched for GO (Gene Ontology) terms related to energy metabolism and were involved in various KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways, including oxidative phosphorylation, TCA (Tricarboxylic Acid) cycle, and sucrose metabolism. These findings indicate that La promotes bahiagrass root growth by improving root activity, photosynthesis, and respiration, which clarifies the mechanisms underlying the beneficial effects of La and provides a theoretical basis for its use in artificial grassland construction and ecological management projects.

Genetic variability and relationship between MT-1 elephant grass and closely related cultivars assessed by SRAP markers.

Genetic variability and relationships among elephant grass cultivars were estimated by the SRAP (sequence-related amplified polymorphism) assay. A total of 60 individuals collected from five cultivars in China were analysed. Sixty-two selected primer combinations generated 1395 bands, with an average of 22.5 per primer combination. The average value of percentage of polymorphic bands (PPB) was 72.8% at species level. The PPB was from 15.2% to 75%, with an average of 39.6% at cultivar level. H(POP), within-cultivar Shannon's index was 1.738 at cultivar level; at species level, the Shannon's index (H(SP)) was 3.880. An assessment of diversity between cultivars (H(SP)-H(POP))/H(SP)] indicated that most of the diversity (55.2%) was detected among cultivars, and only 44.8% was within cultivars in total genetic variation. According to UPGMA dendrogram, the five cultivars were clustered into three main groups. One group included MT-1 and Mott with a bootstrap support of 100%, another consisted of Huanan and N51 with a bootstrap support of 81%, and last one was only Guimu-1. The results indicate that the MT-1 and Mott have a closest genetic relationship; Huanan and N51 possess a relatively close relationship, and Guimu-1 is the most distinct from the other four cultivars.

[Association of phytoplasma with Bermuda grass white-leaf disease].

OBJECTIVE: Bermuda grass white leaf is an important disease on Bermuda grass all over the world. The aim of this research is to identify the pathogen which leads to Bermuda grass white leaf occurring on the Chinese mainland. METHODS: PCR amplification technique, sequence analysis and Southern hybridization were used. RESULTS: A 1.3 kb fragment was amplified by PCR phytoplasma universal primers and total DNA sample extracted from ill Bermuda grass as the amplified template. Sequence analysis of the amplified fragment indicated it clustered into Candidatus Phytoplasm Cynodontis. Southern hybridization analysis showed differential cingulums. CONCLUSION: The pathogen of Bermuda grass white leaf on the Chinese mainland contains phytoplasma, which provides a scientific basis for further identification, prevention and control of the disease.

[Clinical study of yishen jianpi yangxue tongli therapy in treating polycystic ovary syndrome].

OBJECTIVE: To observe the effect of Yishen Jianpi Yangxue Tongli Therapy (YJYTT) in treating polycystic ovary syndrome (PCOS) and to explore the therapeutic mechanism of YJYTT. METHODS: One hundred and seven PCOS patients with syndrome differentiation of TCM as Pi-Shen Yang deficiency were randomly divided into two groups, the treated group (n = 76) was treated with Chinese herbal medicine, while the control group (n = 31) was treated by clomiphen. The therapeutic effect in both groups and the change of body mass index (BMI), Ferriman-Gallway (F-G) score, serum sex hormones and serum oral glucose tolerance test (OGTT) before and after treatment were observed. RESULTS: The comparison of total effective rate between two groups was insignificantly different, but the pregnancy rate of the treated group (65.7%) was markedly higher than that of control group (25.0%, P < 0.01). Also, significant difference was shown in the aspect of BMI, F-G score, serum testosterone (T), luteinizing hormone (LH) and OGTT, etc. between the two groups (P < 0.05). CONCLUSION: The YJYTT could markedly improve the clinical symptoms and pregnancy rate of PCOS patients, particularly showing good effect to the clomiphen resistant patients. The mechanism possibly was due to its regulation on hypothalamus-pituitary-ovarium axis and reducing the insulin resistance.