Biodiversity Of Wheat Rhizobacteria Producing ACC Deaminase And Inoculation Effects On Rainfed Wheat

Existing studies have shown that rhizobacteria with high activity of ACC deaminase can effectively adjust the ethylene metabolism of wheat in sterile pot experiment and increase the drought resistance. On the basis of these studies we expanded the test into farmland, by selecting Yangling and Changwu as two different geographical and climate conditions and investigate and compare the community diversities of bacteria producing ACC deaminase in rhizosphere of wheat growing in these places.1. Use ACC as the sole source of nitrogen to enrich and purify bacteria producing ACC deaminase. Amplify the V3-V4 sequence and detect with Mi-seq high-throughput sequencing platform. From the 2 Changwu samples we got optimized sequence 55 715 bar and was divided into 35 OTUs basing on 97% similarity. The Shannon index is 1.015 and the Simpson’s diversity index is 0.577. Compare the bacterial community structure by R language graph after phylogenetic analysis. Pseudomonas(73.26 %)、Enterobacteriaceae(15.86 %) 、Achromobacter(4.03 %)、Acinetobacter(3.26 %) and Lactococcus(1.87 %) were found to be the domain generas after phylogenetic analysis.From the 2 Yangling samples we got optimized sequence 34 044 bar and was divided into 37 OTUs basing on 97% similarity. The Shannon index is 2.295 and the Simpson’s diversity index is 0.16105. Enterobacteriaceae(37.66 %)、Achromobacter(23.51 %)、Pseudomonas(14.90 %)、Bacillus(9.07 %)、Stenotrophomonas(5.80 %) were found to be the domain generas after phylogenetic analysis. There’s overlop between the rhizobacteria form two areas but differences in abundance and areal variation.2. 35 different strains of rhizobacteria with high activity of ACC deaminase were separated and purified and the highest ACC deaminase activity reached 0.89 U·mg-1.After comparing the ACC deaminase activity and capacity of IAA, it seems that as one index rises, another rises. Considering the IAA play a role as a signal molecule promoting the activity of the ACC synthase, there may be a proper match between IAA generation mechanism and the ACC deaminase after a long history symbiosis of plants and rhizobacteria.3. With inoculating the local bacteria producing high activity of ACC deaminase bacteria separated from Yangling, the growth and development of wheat root system was promoted. And it also contributed to the effective tillering of wheat, reducing the ethylene release after injury and keeping wheat production away from damage. Not only in Yangling, but also can these bacteria play a role of protector of wheat in a strange environment.There are more than 62.96 % overlapping species of bacteria producing ACC deaminase in rhizosphere of wheat between the two areas but larger differences in abundance. It’s a very significant geographical isolation in the spatial distribution. The survey results may guide the development and utilization of plant growth promoting rhizobacteria producing ACC deaminase.