Effect Of Endophytic Bacteria With ACC Deaminase Activity In Kosteletzkya Pentacarpos Confer Plant Salt Tolerance

Kosteletzkya pentacarpos is a kind of high salt tolerance of halophytes,collecting with the energy,oil and health value.This paper introduced different populations of Kosteletzkya pentacarpos from different states of America,plant them in the saline tidal flats of the Yellow River.Found it has a certain amount of salt resistance,so endophytic bacteria were isolated from the roots and inoculate to 4 kinds of plants wish them to obtain slat resistance.Studies has shown that the ACC deaminase have effect of plant growth promotion,this paper has measured the ACC deaminase activity of the endophytic bacteria and use them to inoculated Glycine max,Triticum,Arabidopsis thaliana and Kosteletzkya pentacarpos,and respectively measured the plant growth index and physiological index under salt stress and without salt.Cloned the ACC deaminase gene acdS of Bacillus cereus,which has the highest ACC deaminase activity,and make it express in E.coli DH5? cell,and measured the salt resistance of E.coli containing the recombinant plasmid.43 endophytic bacteria strains,isolated from roots of the halophyte Kosteletzkya pentacarpos,belong to ten genus by 16 S rDNA sequencing and the identification of morphological features.They are respectively Bacillus cereus,Bacillus pumilus,Bacillus megaterium,Bacillus licheniformis,Pseudomonas chlororaphis,Agrobacterium tumefaciens,Paenibacillus sp.,Arthrobacter crystallopoietes,Pseudomonas mandelii,Bacillus subtilis.Among them,Bacillus is the advantage genus,and then is Pseudomonas and Agrobacterium.Bacillus cereus and Bacillus licheniformis are the advantage species.ACC deaminase activity of endophytic bacteria in Kosteletzkya pentacarpos has been determined.Results reveal that five strains can produce obvious ACC deaminase activity.These five kinds of bacteria were used to inoculate wheat and Kosteletzkya pentacarpos roots under salt stress to determine their effects on the salt resistance of different plant.Also use the ACC deaminase activity strong Bacillus cereus and Bacillus licheniformis to infect Glycine max seedlings and Arabidopsis thaliana seedlings.Data showed that four strains,including Bacillus cereus,Bacillus megaterium,Bacillus pumilus and Bacillus licheniformis,could not only promote the Triticum,Kosteletzkya pentacarpos,Glycine max and Arabidopsis thaliana fresh weight,dry weigh and chlorophyll content under salt stress,but also raise SOD,POD,CAT enzyme activities significantly,showing elite alleviating capacity to the salt toxicity.Additionally,Pseudomonas chlororaphis,to a certain extent,also showed the promotive effects on wheat plant height,root length,fresh weight,dry weight and chlorophyll content.These suggested that all the five endophytic bacteria isolated from Kosteletzkya pentacarpos with ACC deaminase can enhance the salt resistance of four different seedings.Cloned ACC deaminase gene acdS of Bacillus cereus,gene size 996 bp,can express a polypeptide of 331 amino acid residues.The sequencing results show that this gene of endophyte separate form Kosteletzkya pentacarpos was high coincidence with Bacillus cereus E33 L.Transformed the acdS gene into E.coli competent cell DH5?,and expressed,result show that it has improved the salt resistance of E.coli.It indicates that the salt resistance improvement of plants and E.coil comes from ACC deaminase.So ACC deaminase has function to improve salt resistance of plants and bacteria.