Structure and ecological function of the soil microbiome affecting plant-soil feedbacks in the presence of a soil-borne pathogen.

Interactions between plants and soil microbes are important for plant growth and resistance. Through plant-soil-feedbacks, growth of a plant is influenced by the previous plant that was growing in the same soil. We performed a plant-soil feedback study with 37 grass, forb and legume species, to condition the soil and then tested the effects of plant-induced changes in soil microbiomes on the growth of the commercially important cut-flower Chrysanthemum in presence and absence of a pathogen. We analysed the fungal and bacterial communities in these soils using next-generation sequencing and examined their relationship with plant growth in inoculated soils with or without the root pathogen, Pythium ultimum. We show that a large part of the soil microbiome is plant species-specific while a smaller part is conserved at the plant family level. We further identified clusters of plant species creating plant growth promoting microbiomes that suppress concomitantly plant pathogens. Especially soil inocula with higher relative abundances of arbuscular mycorrhizal fungi caused positive effects on the Chrysanthemum growth when exposed to the pathogen. We conclude that plants differ greatly in how they influence the soil microbiome and that plant growth and protection against pathogens is associated with a complex soil microbial community.

Exercise Training for Improving Patient-Reported Outcomes in Patients With Advanced-Stage Cancer: A Systematic Review and Meta-Analysis.

CONTEXT: Patients with advanced-stage cancer often suffer many physical and psychological symptoms. Exercise has been shown to improve quality of life (QoL), decrease cancer-related symptoms, and maintain or improve functional status in cancer survivors or patients with early stage cancer. However, the effect of exercise on these outcomes in patients with advanced-stage cancer is unclear. OBJECTIVES: This meta-analysis aimed to assess the effectiveness of exercise interventions for patients with advanced-stage cancer in improving cancer-related symptoms and functional status outcomes. METHODS: We conducted a comprehensive literature search in PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Web of Science from their inception to February 3, 2019, to include randomized controlled trials (RCTs) comparing exercise and usual care for improving outcomes in patients with advanced-stage cancer. Two reviewers independently screened the studies, extracted data of interest, and assessed the risk of bias of individual RCTs using the Cochrane Handbook, Version 5.1.0. RESULTS: About 15 RCTs enrolling 1208 patients were included. Compared with usual care, exercise showed a significant improvement in QoL (standardized mean difference [SMD] 0.22; 95% CI 0.06-0.38; P = 0.009), fatigue (SMD -0.25; 95% CI -0.45 to -0.04; P = 0.02), insomnia (SMD -0.36; 95% CI -0.56 to -0.17; P = 0.0002), physical function (SMD 0.22; 95% CI 0.05-0.38; P = 0.009), social function (SMD 0.18; 95% CI 0.02-0.34; P = 0.03), and dyspnea reduction (SMD -0.18; 95% CI -0.34 to -0.01; P = 0.03). CONCLUSION: Exercise serves as an effective intervention to improve QoL and alleviate fatigue, insomnia, dyspnea, and physical and social functions for patients with advanced-stage cancer.

Optimal interval to surgery after chemoradiotherapy in rectal cancer: A protocol for systematic review and network meta-analysis.

BACKGROUND: Rectal cancer is the second leading cause of cancer-related death in the Western world. Preoperative neoadjuvant chemoradiotherapy (nCRT) has been widely performed in the treatment of rectal cancer patients. However, there is no consensus on the length of waiting interval between the end of preoperative nCRT and surgery. Present network meta-analysis (NMA) aims to compare the differences of effect between all available interval to surgery after nCRT in rectal cancer in improving overall survival, disease-free survival and pathologic complete response (pCR) rate, and to rate the certainty of evidence from present NMA. METHOD: We will systematically search PubMed, EMBASE, Chinese Biomedical Literature Database, and Cochrane Central Register of Controlled Trials (CENTRAL) databases to identify studies assessing the interval to surgery after CRT in rectal cancer. We will conduct this systematic review and meta-analysis using Bayesian method and report the full-text according to Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) Extension Vision statement (PRISMA-NMA). We will assess the risk of bias of individual study using the Newcastle-Ottawa Scale and Cochrane Handbook V.5.1.0. We will also use the advance of GRADE to rate the certainty of NMA. Data will be analyzed by using R software V.3.4.1. RESULTS: The results of this study will be published in a peer-reviewed journal. CONCLUSION: To the best of our knowledge, this systematic review and NMA will first use both direct and indirect evidence to compare the differences of all available interval to surgery after CRT in rectal cancer. This is a protocol of systematic review and meta-analysis, so the ethical approval and patient consent are not required.

Synergistic and antagonistic effects of mixing monospecific soils on plant-soil feedbacks.

BACKGROUND AND AIMS: Plants influence the soil they grow in, and this can alter the performance of other, later growing plants in the same soil. This is called plant-soil feedback and is usually tested with monospecific soils, i.e. soils that are conditioned by one plant species. Here, we test if plant-soil feedbacks of inocula consisting of mixtures of monospecific soils can be predicted from the effects of the component inocula. METHODS: Chrysanthemum plants were grown in sterile soil inoculated with eight monospecific conditioned soils and with mixtures consisting of all pairwise combinations. Plant biomass and leaf yellowness were measured and the additivity was calculated. RESULTS: On average, plant biomass in the mixed inocula was slightly but significantly (6%) lower than predicted. In contrast, when growing in mixed inocula, plants showed 38% less disease symptoms than predicted. Moreover, the larger the difference between the effects of the two monospecific soils on plant growth, the higher the observed effect in the mixture exceeded the predicted effects. CONCLUSIONS: We show that mixed monospecific soils interact antagonistically in terms of plant growth, but synergistically for disease symptoms. Our study further advances our understanding of plant-soil feedbacks, and suggests that mixing soils can be a powerful tool to steer soil microbiomes to improve plant-soil feedback effects.

Plant-Soil Feedback Effects on Growth, Defense and Susceptibility to a Soil-Borne Disease in a Cut Flower Crop: Species and Functional Group Effects.

Plants can influence the soil they grow in, and via these changes in the soil they can positively or negatively influence other plants that grow later in this soil, a phenomenon called plant-soil feedback. A fascinating possibility is then to apply positive plant-soil feedback effects in sustainable agriculture to promote plant growth and resistance to pathogens. We grew the cut flower chrysanthemum (Dendranthema X grandiflora) in sterile soil inoculated with soil collected from a grassland that was subsequently conditioned by 37 plant species of three functional groups (grass, forb, legume), and compared it to growth in 100% sterile soil (control). We tested the performance of chrysanthemum by measuring plant growth, and defense (leaf chlorogenic acid concentration) and susceptibility to the oomycete pathogen Pythium ultimum. In presence of Pythium, belowground biomass of chrysanthemum declined but aboveground biomass was not affected compared to non-Pythium inoculated plants. We observed strong differences among species and among functional groups in their plant-soil feedback effects on chrysanthemum. Soil inocula that were conditioned by grasses produced higher chrysanthemum above- and belowground biomass and less leaf yellowness than inocula conditioned by legumes or forbs. Chrysanthemum had lower root/shoot ratios in response to Pythium in soil conditioned by forbs than by grasses. Leaf chlorogenic acid concentrations increased in presence of Pythium and correlated positively with chrysanthemum aboveground biomass. Although chlorogenic acid differed between soil inocula, it did not differ between functional groups. There was no relationship between the phylogenetic distance of the conditioning plant species to chrysanthemum and their plant-soil feedback effects on chrysanthemum. Our study provides novel evidence that plant-soil feedback effects can influence crop health, and shows that plant-soil feedbacks, plant disease susceptibility, and plant aboveground defense compounds are tightly linked. Moreover, we highlight the relevance of considering plant-soil feedbacks in sustainable horticulture, and the larger role of grasses compared to legumes or forbs in this.

A Comparison of Novel Entomopathogenic Nematode Application Methods for Control of the Chive Gnat, Bradysia odoriphaga (Diptera: Sciaridae).

Bradysia odoriphaga Yang & Zhang (Diptera: Sciaridae) is the most serious pest of Chinese chive, Allium tuberosum Chemical pesticide application has become a necessary step to control B. odoriphaga after each of the four to six harvests during the growing season. We compared the effects of application type (nematode-infected cadaver, aqueous nematode suspension, and mixture of cadaver and aqueous suspension) and nematode species (Heterorhabditis bacteriophora vs. Steinernema carpocapsae) on B. odoriphaga control. Nematode species combinations and the use of the cadaver method has only been tested in a relatively few studies, and has not been tested for this target pest, B. odoriphaga. Furthermore, this is the first report of combining application methods (aqueous and cadaver). Results indicated that the cadaver treatment produced higher mortality of B. odoriphaga than the aqueous treatment, and H. bacteriophora caused higher mortality of B. odoriphaga than S. carpocapsae. The mortality of B. odoriphaga was 96.7% in H. bacteriophora cadaver treatment and only 27.5% in control treatment without nematode addition. Cadaver treatments caused higher biomass of A. tuberosum than that of aqueous treatment. The plant biomass in H. bacteriophora cadaver treatment was 10 folds as much as that in the control treatment. The mixed aqueous suspension of H. bacteriophora and S. carpocapsae did not increase the mortality in pot trial. Our findings indicate that entomopathogenic nematodes applied as cadavers might be a potential alternative biological agent in the integrated management of B. odoriphaga for Chinese chive production.