Research Of N-acyl-homoserine Lactones Regulation Of Arabidopsis Salt Resistance And Its Binding Characteristics With GCR2

Because of the global climate drought and other adverse factors, it led to the global land salinization aggravated, causing serious damage to agricultural production. Salt stress is a main kind of abiotic stress, which can inhibit the growth of plant, reduced crop yield and others. To improve plant salt tolerance has been the focus of the study. The Soil Rhizosphere of some non-pathogenic bacterium on plant growth and development has a positive effect. N-acyl homoserine lactone(AHLs) are a class of quorum sensing signal of gram negative bacterial secretion. It can be perceived by plant and influence on plant metabolism. The long chain of AHLs can improve the disease resistance in plants has been studied. However, molecular mechanisms of how plants recognizing and accepting AHLs is less clear.This research based on the before results. Preliminarily research showed that GCR2 was receptor of 3OC6-HSL by Microscale thermophoresis and Liquid scintillation assays. This experiment used Arabidopsis thaliana as experimental materials. 3OC6-HSL had strong ability of salt resistance from a variety of AHLs. It could improve salt resistance and root growth of Arabidopsis obviously. In order to clarify the molecular mechanism of 3OC6-HSL to improve the salt resistance of Arabidopsis,this research analysised of changes of physiological and biochemical and the molecular level after 3OC6-HSL treatment under the salt stress. The results were as follows:1. By the technology of MST measured Kd of 3OC6-HSL and GCR2 was 76.1±0.515 n M. Liquid scintillation assay measured Kd of 3H-3OC6-HSL and GCR2 was 62.4495±4.2671 n M. Taking BSA, OVA, denatured GCR2 as negative control, 3OC6-HSL had no significant binding with these. Liquid scintillation detection the combination of 3OC6-HSL and GCR2 was reversible. Results preliminarily demonstrated that GCR2 may acted as a receptor for 3OC6-HSL.2. The experiment found that C4-HSL, 3OC6-HSL, C8-HSL, 3OC8-HSL and 3OC12-HSL had salt resistance. The 3OC6-HSL had a strong role in salt resistance ability and promoted primary root elongation of Arabidopsis. 1 μM 3OC6-HSL could enhance the salt tolerance of Arabidopsis in 120 m M Na Cl stress. 3OC6-HSL could promote seed germination in 80 or 100 m M Na Cl stress.3. 3OC6-HSL could increase the content of chlorophyll a and inhibition the content of chlorophyll b in Arabidopsis. It could also reduce the Na+, Ca2+ content and increase the content of K+ in Arabidopsis. Under salt stress 3OC6-HSL treatment group of chlorophyll a content of was higher than Na Cl treatment group. Under salt stress, 3OC6-HSL pretreatment group of the content of chlorophyll a and chlorophyll b were increased higher than Na Cl treatment group. In addition, 3OC6-HSL could promote stomatal closure.4. 3OC6-HSL could regulate expression of GCR2, MPK6, CAM9, JAR1, SOS2 and ABA1. 3OC6-HSL couldn’t significantly promote the expression of RD29 B, RD22, ERD1, COR15 A and ABA1 directly. Under salt stress, 3OC6-HSL simulted expression ABA1 of ABA synthetic pathway group and COR15 A, RD29 B, RD22 of ABA dependent signal. Instead of ERD1 of undependent on ABA signal pathway did not significantly up-regulated.