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The possibility of utilization of feather powder and rapeseed cake as solid- state fermentation media to produce bio-organic fertilizers with plant growth-promoting rhizobacteria(PGPR) strain Bacillus amyloliquefaciens NJN-6 was investigated in this study. The results showed that addition of rapeseed cake and feather powder efficiently solid-state fermented PGPR strain NJN-6 with the optimum additive amount of 100 g·kg-1 ( dry weight), improved the nutrient contents in the novel bio-organic fertilizers and significantly promote banana plant growth. After transplanting for 40 days,the fresh biomass of the above-and below-ground parts of banana plants in treatment 2 supplied with bio-organic fertilizer produced by adding rapeseed cake were 1. 26 and 1. 16 times of that in the CK supplied with chemical fertilizer,and increased by 28. 7% and 31. 2% compared to the treatment 1 supplied with bio- organic fertilizer produced with no exogenous protein resource,while the value for banana plants in treatment 3 treated by bio-organic fertilizer produced by feather powder addition was 1. 18 and 1. 12 times,and increased by 20. 6% and 26. 9%,respectively. After transplanting for 70 days, compared to treatment 1, treatment 2 increased the plant height and stem diameter by 25. 95% and 10-72%,respectively,while treatment 3 increased by 16. 22% and 8. 74%,respectively. In conclusion,although the bio-organic fertilizer supplemented with rapeseed cake more significantly promoted banana growth than that supplemented with feather powder, the latter one still had certain advantages in solid-state fermentation of the PGPR strain and promoting banana growth,indicating a possibility to produce bio-organic fertilizer(BOF)using feather powder. [ABSTRACT FROM AUTHOR]

[Objectives] Potassium efficient absorption is beneficial to yield and quality of watermelon. It is significant on screening potassium efficient genotypes of watermelon for resource utilization and efficient potassium mechanism research. [Methods] Thirty three popular watermelon cultivars in practice were selected to screen efficient potassium genotypes. Pot experiment was carried out to screen potassium efficiency genotype and inefficiency genotype on both low and high potassium application. Small type and big-mid type watermelons were selected respectively. [Results] Potassium efficiency could be estimated by potassium absorption of watermelon seedling on the condition of low and high potassium supply. Potassium content made great contributions to potassium absorbing capacity. 'Xiaoxiacheng' 'Xinlan' 'Zaochunhongyu' of small type genotypes and'Heijuba' 'Tedatainongbahao' and' Xinheilongwang' of big-mid type genotypes were dual efficient potassium genotype. 'Jintong' 'Huangxiaoyu-H' of small type genotypes and 'Ping87-14' and 'Kangbingdilei' of big-mid type genotypes were dual inefficient potassium genotypes. Potassium acquisition of high efficient 'Xiaoxiacheng' was higher by 202.7% and 280.0% than that in inefficient 'Jintong' at low and high potassium application, respectively. Potassium acquisition of high efficient 'Heijuba' was higher by 287.4% and 77.1% than that in inefficient 'Ping 87-14' at low and high potassium application, respectively. Cluster analysis by potassium absorption, potassium utilization index and potassium transfer ratio showed that 'Zaochunhongyu' and 'Xinlan', 'Xinheilongwang' and 'Heijuba', 'Zaojia84-24' 'Ping87-14' and 'Kangbingdilei' were similar, respectively. [Conclusions] Potassium absorption efficiency of watermelon could be estimated by potassium acquisition and potassium content. Both potassium absorption efficiency and cluster analysis showed that 'Xiaoxiacheng' of small type watermelon and 'Heijuba' of big-mid type watermelon were efficient genotypes, while 'Jintong' of small type watermelon and 'Ping 87-14' of big-mid type watermelon were inefficient genotypes. [ABSTRACT FROM AUTHOR]

[Objectives]The objective of this study was to get deeper insight in the effect of fenarimol application on Magnaporthe poae and fungi properties in the M.poae infected soil. [Methods]Based on the 18s rRNA internal transcribed spacer(ITS)gene,two metagenomic libraries from control and fenarimol treated rhizosphere soil were constructed,and deeper sequencing was carried out by Illumina Genome Analyzer(GA)technology. [Results]There were 4 851 438 and 3 037 924 Illumina reads generated from control and fenarimol treated rhizosphere soil samples,which were further clusterd to 28 219 and 21 288 repetitive operational taxonomic unit(OTU). After fenarimol treated,Ascomycota decreased 18% compared with the control, while Basidiomycota increased 32%,and there were no significant changes of Chytridiomycota and Glomeromycot. In addition,there were 7 phyla,152 genera and 200 fungi species that disappeared after fungicide application. [Conclusions]Fenarimol had significant suppression on M.poae and Phoma, Leptosphaeria, Fusariuma, Phialophora communities in rhizosphere soil. [ABSTRACT FROM AUTHOR]

[Objectives] Rape-seed cake compost (RC) is an important nutrient carrier for biocontrol microorganisms in the production of bio-organic fertilizer(BOF). To enhance BOF control efficiency, herein we are aiming to screen bacterial strains that efficiently inhibit Rahtonia solanacearum, the causative agent of bacterial wilt of tomato, by using RC as the sole nutrients. [Methods] Bacterial antagonists were selected from tomato rhizosphere soils on nutrient agar( NA)and RC(8% RC in water) plates. Greenhouse assay was carried out to evaluate the efficiencies of bacterial antagonists fortified with RC on the suppression of R. solaruwearum. [Results] Antagonistic strain NA-5 isolated from NA plate performed best in inhibiting R. solanacearum growth on NA plate; with an inhibition zone; diameter of 29.0 mm, while weak inhibition effect was observed on RC plate. Interestingly, strain RC-14 isolated from RC plates showed a remarkable inhibition zone diameter of 24 mm on RC plate. Greenhouse results showed that both NA-5 and RC-14 fortified BOF (coded as B0F5 and BOF 14,respectively) significantly reduced disease incidences. BOF14 ha 1 significant higher biocontrol efficiency(75.9%) than BOF5. The R. solanacearum population in the rhizosphere soil of BOF14 treatment was significantly lower than BOF5 and other treatments(soil amended with RC, biocontrol agents or nothing). Based on the results of morphologic characteristics and analysis of 16S rRNA gene sequences, Strain RC-14 was preliminarily identified as Geohacillus sp. [Conclusions] Our results clearly demonstrated that using this screen strategy (ran obtain novel potential biocontrol agents, as little information was found about application of Geohacillus sp. for biocontrol of R. solanacearum. Geohacillus sp. strain RC-14 might produce more antibiotics against R. solanacearum in tomato rhizosphere when RC was taken as the nutrient carrier. [ABSTRACT FROM AUTHOR]

[Objectives] A better method for evaluation of the degradation ability of rice straw-degrading bacteria was explored. [Methods] Ten strains of straw-degrading bacteria were used to study the relationship between the hydrolysis ring(on CMC-Na plate) , carboxymethyl cellulose (CMCase)and xylanase activity in rice straw powder as carbon source for liquid fermentation medium and the relative degradation rate of rice straw. [Results] The hydrolysis zone diameter on CMC-Na plate(D) , the ratio of hydrolysis zone to colony diameter( D/d) , the largest CMCase and xylanase activities of each day of strains were not significantly correlated with their relative degradation rate(RDR)on rice straw( P>0.05). Positive correlations were observed between the CMCase or xylanase activities accumulated for one week and RUR(P<0.05) , while the total cumulative enzyme(CMCase plus xylanase) activity in one week was significantly correlated with RDR (P<0.01). [ Conclusions] The cumulative enzyme activity of strain is better to evaluate the actual degradation effects, and this new evaluation method provides a more accurate identification of reference for the degradation ability of the straw-degrading bacteria. [ABSTRACT FROM AUTHOR]

Efficient colonization of plant growth-promoting rhizobacteria (PGPR) on plant roots is crucial for the exertion of the growth promotion and bio-control effects. This study was performed to investigate the colonization patterns of Bacillus amyloliquefaciens SQR9 on banana roots to understand its application prospect on plant growth and biological control. The colonization patterns of B. amyloliquefaciens SQR9 tagged by green fluorescence protein(GFP)on banana roots was investigated in hydroponic and natural soil system by confocal laser scanning microscopy(CLSM)and scanning electron microscopy(SEM). The results showed that SQR9 carrying gfp(SQR9-gfp)could effectively colonize on banana roots and formed micro-colonies at 2 to 4 days of inoculation. The colonization of bacterial cells mainly occurred on the differentiation and elongation zones of the main roots, the lateral roots, junctions between roots and the root hairs, while few labeled bacterial cells were detected to attach along the root tips. In addition, similar colonization patterns of SQR9-gfp were obtained under both systems suggested that the hydroponic system could represent the natural soil system in a short time. The quantitative analysis revealed that at 4 days after inoculation, the population of SQR9-gfp was maintained at about 105-106 CFU·g-1 roots, and 106-107 CFU·g-1 soil, respectively; While the abundance of SQR9 slightly decreased at 15 days post inoculation. Conclusions:SQR9 could effectively colonize on banana roots and reach the appropriate population, which could provide the theoretical basis for the practical application of SQR9 for suppression of banana wilt. [ABSTRACT FROM AUTHOR]

In order to explore the effect of returning whole straw associated with combined cow manure and reduced chemical fertilizer application on grain yield, uptake and use of nitrogen under rice-wheat rotation system in Tai Lake region, an experiment was laid out with randomized design with four replicates of five treatments, respectively, CK(non-fertilization), CF(inorganic fertilizer that N application was 240 kg·hm-2), OMCF(70%CF with 3 000 kg·hm-2 cow manure), CF+S(CF+returning whole straw)and OMCF+S(OMCF+returning whole straw). Each plot was 46 m2 in area and isolated by plastic waterproof membrane to prevent the water and nutrients exchange between plots. The soil in ploughed layer before the experiment contained 21.5 g•kg-1 soil organic matter, 2.30 g·kg-1 total nitrogen, 0.93 g·kg-1 total phosphorus, 140 mg·kg-1 available nitrogen, 39.0 mg·kg-1 available phosphorus, 74.3 mg·kg-1 available potassium and pH 7.6. The grain yield and yield component, accumulation, distribution and translocation of nitrogen and dry matter aboveground, N use efficiency and amount of soil mineral nitrogen at each treatment were measured/calculated for comparison. The results showed that change rule of grain yield in treatments as follows:OMCF+S, CF+S, OMCF, CF, CK, application of organic fertilizer promoted sink capacity and thousand seed weight. Application of returning whole straw associated with combined cow manure and reduced chemical fertilizer promoted dry matter accumulation and nitrogen uptake, and also increased the distribution of dry matter and N to the grain at mature, which was beneficial for the transformation from biological yield to economic yield. It also improved assimilation of dry matter at filling stage and translocation of N in vagetative, and thereby promoted nitrogen use efficiency. The increment of OMCF+S treatment's nitrogen use efficiency was more obvious than OMCF or CF+S separately as a result of cooperative action of returning whole straw and cow manure. The increased content of soil mineral nitrogen at mid-late growth stage by application of returning whole straw or cow manure, especially OMCF+S, improved nutritional conditions at mid-late growth stage of crop, improved young spike differentiation and grain-filling, and laid a foundation for increment of grain yield. Conclusions: Cooperative action of straw returning and combined application of cow manure and chemical fertilizer improved the coordination of yield component at a higher level, and higher yield was obtained, meanwhile, it improved N use efficiency by the realization of self-regulation of crop-soil. [ABSTRACT FROM AUTHOR]

Summer patch is a destructive disease of Kentucky bluegrass (Poa pratensis) caused by Magnaporthe poae, which usually begins to emerge when the soil temperature and humidity are high. In this study, we sequenced 24 Magnaporthe and its related strains based on the ITS1-5.8S-ITS2 gene, and then investigated the ITS phylogennetic characterization. The results suggested that stains of M.poae and its related species distributed to two phylogennetic groups(A and B). M. oryzae and Pyricularia oryzae formed group A and was further divided into two clades, suggesting that M. oryzae is more closely related to P. oryzae, these species infect both root and aerial parts of the plant host. Group B contains M. salvinii, M. poae, M. rhizophila, Gaeumannomyces incrustans, G. graminis var. graminis and G. graminis var. tritici. These species of group B could infect root aparts of the plant host when excluding M. salvinii. In the turf environment, the detection of the species of group B is more difficult than that of group A if by morphological detection. Based on the molecular characterization of ITS gene, we produced a macroarray, which included three types of oligonucleotide probes: monomers (20-24 bp), dimers (40-48 bp), and monomers with a poly-A tail of 20 (30-44 bp) bases, respectively. The results showed that M. poae, G. incrustans and G. graminis of group B could be quickly detected and identified by the designed array. The detect sensitivities of dimers are significantly higher than the monomers-A20, still higher than monomers. The use of repeat sequence probes (dimers) greatly improved the sensitivity of the macroarray, which can be used in turf pathogen detection in the future. [ABSTRACT FROM AUTHOR]

In this study, phosphate solubilizing bacteria(PSB)were screened from rhizosphere soil and root of maize and elephantgrass using modified Pikovskaya(PVK)plate method, and phosphate-solubilizing activity of these strains was determined by measuring the soluble P concentration in National Botanical Research Institute's Phosphate(NBRIP)broth. In addition,3 strains designated as X14, X32,and Y21 were tested in the laboratory for their ability to colonize the rhizosphere of maize seedlings in sterile quartz sand. Finally, a pot trial was carried out in greenhouse to evaluate whether the laboratory test can predict beneficial effects of PSB on maize. The results showed that soluble P concentration in NBRIP broth of strain X14 was significantly lower than that of strain X32 and Y21,which was 22.80% and 19.99% of strain X32 and Y21,respectively. However, strain X14 was found to be a better rhizosphere colonizer than that of strain X32 and Y21,whose final population in the rhizosphere of maize seedlings expressed as CFU.g-1 was an order of magnitude higher than that of strain X32 in equal inoculum size. Under greenhouse conditions, application of PSB remarkably improved plant diameter,shoot height,fresh and dry weight,and P uptake of maize as compared to the control,but there was no significant difference between treatments inoculated with PSB. The strains X14, X32, and Y21 were identified under the genera Bacillus, Acinetobacter, and Pseudomonas using 16S rDNA sequences in comparison with GenBank database. This study showed that the phosphate-solubilizing activity of strain X14 was significantly lower than that of strain X32 and Y21 in the laboratory test, but its beneficial effect on P uptake of maize was equal to that of strain X32 and Y21 in the pot trail because of its better colonization in the rhizosphere of maize. So screening of PSB should be based on the colonization ability of strain in the rhizosphere of plant. [ABSTRACT FROM AUTHOR]