Identification of Growth-promoting Bacteria from Rhizosphere of Pastures and Their Effects on Growth of Lotus corniculatus L.

[Objectives] This study was conducted to explore the interaction between nitrogen-fixing and phosphate-solubilizing strains and the optimal combination of different functional strains,in order to provide a theoretical basis for the development of PGPR compound fertilizers suitable for local environment.[Methods] In this study,16S rDNA gene sequence analysis was used to identify fast-growing and competitive strains from pasture nodules and rhizosphere soils in Guizhou Province,and three representative Rhizobia and phosphorus-solubilizing bacteria were chosen for the test of bacterial combination when reducing 50% of nitrogen and 30% of phosphorus.The effects of different strain combinations on the plant height,root length,aboveground and underground biomass of Lotus corniculatus L.were investigated,and the total nitrogen and total phosphorus contents of the plants were determined.[Results] The mixed bacterial agents could promote the increase of root biomass,and the effects of A1,A3,B3 and C3 were the most obvious.The fresh weight and dry weight of the roots of L.corniculatus increased by 30.35%-168.45% and 26.43%-180.00%,respectively,and A3,B3,B2 and C3 had the best effects.The total phosphorus content of the plants increased by 12.79%-55.25% compared with the CK2;and most of the bacterial agents with significant growth-promoting effects showed decreased total nitrogen contents,while those with non-significant growth-promoting effects showed significantly-increased total nitrogen contents,which were not as much as the CK1.Comprehensively,the most productive combination was C3,namely R27-2 Rhinohizobium fredii and P33-3 Stenotrophomonas rhizophila.[Conclusions] This study can provide a theoretical basis for the production and promotion of bacterial fertilizers.

Cloning and Bioinformatics Analysis of FaPHYC Gene in Tall Fescue (Festuca arundinacea)

The cDNA of PHYC gene of tall fescue ( Festuca arundinacea ) was cloned by RT-PCR,named FaPHYC.The sequence was analyzed by bioinformatic software,and the results showed that the full-length cDNA(3816 bp) was obtained with an open reading frame predicated to be 3 411 bp,which encoded 1 136 amino acids.By BLASTP analysis,the N-terminal of FaPHYC was composed of GAF and pPhytochrome domains,and its C-terminal included two repeated PAS domains,one histidine kinase A domain and one histidine kinase-like ATPase domain.The phylogenetic analysis showed that FaPHYC was closely related to PHYCs from other Gramineae plants.The qRT-PCR results showed that FaPHYC expression was regulated by drought stress,heat stress,salt stress and nitrogen stress.The real-time quantitative PCR assay showed the expression of FaPHYC in tall fescue seedlings was continuously up-regulated during the light period and down-regulated in the dark.The results suggest that FaPHYC is photoperiod sensitive and plays a functional role in flowering regulation by photoperiod in tall fescue.The FaPHYC gene was cloned and reported from tall fescue for the first time,which lays a foundation for the investigation of the stress mechanism of FaPHYC in tall fescue plant.