[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...[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.展开更多
A simple and effective system for the transformation and regeneration of a leguminous plant has been developed. The cotyledon explants of Lotus corniculatus (var. Leo) were infected by Agrobacterium tumefaciens that c...A simple and effective system for the transformation and regeneration of a leguminous plant has been developed. The cotyledon explants of Lotus corniculatus (var. Leo) were infected by Agrobacterium tumefaciens that contained a non-oncogenic Ti plasmid vector. The vector carried a chimaeric npt-Ⅱ gene and a nopaline synthase gene (nos). On the selective medium that contained kanamycin, 40% of the explants formed buds within 3 weeks. Developed shoots were cut off and transferred to rooting medium. Normal-looking plants were recovered and grew well after being transplanted into soil, bloomed and set seeds. Foreign genes were integrated onto the L. corniculatus genome, expressed, and inherited through sexual reproduction, which was proven by nopaline detection, NPT-Ⅱ enzyme activity detection and DNA hybridization test of the transformed plants and the nopaline detection of the progeny.展开更多
The full length cDNA coding for a novel vacuolar Na+/H+ antiporter (GmNHX1) was cloned from soybean and determined to consist of 2591 bp with a 5′-untranslated region of 464 bp, an open reading frame (ORF) of 1641 bp...The full length cDNA coding for a novel vacuolar Na+/H+ antiporter (GmNHX1) was cloned from soybean and determined to consist of 2591 bp with a 5′-untranslated region of 464 bp, an open reading frame (ORF) of 1641 bp, and a 3′-untrans- lated region of 486 bp. The deduced protein se- quence contains 546 aa with the typical characters of the vacuolar Na+/H+ antiporters, and shares high similarity with that of AtNHX1, OsNHX1 and AgNHX1. The soybean genome showed a single copy of the GmNHX1 gene. Northern blot analysis demonstrated that the expression of the GmNHX1 was tissue-spe- cific, increased by ABA treatment, NaCl, KCl, LiCl and dehydration stress, and lower in leaves but higher in roots and hypocotyls of salt-tolerant than salt-sensitive cultivars. The GmNHX1 was overex- pressed under the control of a tandem cauliflower mosaic virus (CaMV) 35S promoter in the model le- guminous plant Lotus corniculatus L. and conferred salt-tolerance of the transgenic plants. Measure- ments of Na+ and K+ contents in both roots and shoots demonstrated that the plantlets of GmNHX1- overexpressing lines had lower Na+ and K+ content, and higher K+/Na+ ratio than the controlled lines that were transformed with the empty vector, which indi- cates that the salt-tolerance conferred by GmNHX1 is closely related with decreased accumulation of Na+ in the transgenic plants.展开更多
基金Supported by Guizhou Province Science and Technology Support Program(QKHZC[2016]2504,[2019]2359)
文摘[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.
文摘A simple and effective system for the transformation and regeneration of a leguminous plant has been developed. The cotyledon explants of Lotus corniculatus (var. Leo) were infected by Agrobacterium tumefaciens that contained a non-oncogenic Ti plasmid vector. The vector carried a chimaeric npt-Ⅱ gene and a nopaline synthase gene (nos). On the selective medium that contained kanamycin, 40% of the explants formed buds within 3 weeks. Developed shoots were cut off and transferred to rooting medium. Normal-looking plants were recovered and grew well after being transplanted into soil, bloomed and set seeds. Foreign genes were integrated onto the L. corniculatus genome, expressed, and inherited through sexual reproduction, which was proven by nopaline detection, NPT-Ⅱ enzyme activity detection and DNA hybridization test of the transformed plants and the nopaline detection of the progeny.
文摘The full length cDNA coding for a novel vacuolar Na+/H+ antiporter (GmNHX1) was cloned from soybean and determined to consist of 2591 bp with a 5′-untranslated region of 464 bp, an open reading frame (ORF) of 1641 bp, and a 3′-untrans- lated region of 486 bp. The deduced protein se- quence contains 546 aa with the typical characters of the vacuolar Na+/H+ antiporters, and shares high similarity with that of AtNHX1, OsNHX1 and AgNHX1. The soybean genome showed a single copy of the GmNHX1 gene. Northern blot analysis demonstrated that the expression of the GmNHX1 was tissue-spe- cific, increased by ABA treatment, NaCl, KCl, LiCl and dehydration stress, and lower in leaves but higher in roots and hypocotyls of salt-tolerant than salt-sensitive cultivars. The GmNHX1 was overex- pressed under the control of a tandem cauliflower mosaic virus (CaMV) 35S promoter in the model le- guminous plant Lotus corniculatus L. and conferred salt-tolerance of the transgenic plants. Measure- ments of Na+ and K+ contents in both roots and shoots demonstrated that the plantlets of GmNHX1- overexpressing lines had lower Na+ and K+ content, and higher K+/Na+ ratio than the controlled lines that were transformed with the empty vector, which indi- cates that the salt-tolerance conferred by GmNHX1 is closely related with decreased accumulation of Na+ in the transgenic plants.
