Plant Endophytic Bacteria Salinicola Tamaricis F01 Effects On Physiological And Biochemical Function Of Suaeda Salsa

Endophytes live in various tissues and organs of healthy plants at a certain stage or all stages of their life.Host plants which are infected do not exhibit external symptoms?at least temporarily?^[1].They can co-exist in plants,and after prolonged co-evolution,become an important part of the plant's ecosystem.Plants and most endophytic bacteria living in their bodies are mutually beneficial symbiotic relationship.For example,endophytes can promote plant growth and development due to their metabolites,and improve plant resistance to stress,while plants provide essential ecological environment,nutrient and energy substance.In addition,some endophytes tend to have anti-heavy metals and high salt tolerance,which is beneficial to halophytes improve saline-alkali land and protect environment.The halophyte,Suaede salsa,plays an important role in the improvement of saline-alkali soils.It is reported that it can significantly reduce soil salinity and improve soil property,and is a pioneer species to improve saline-alkali land^[2].Under salt stress,a large number of osmotic adjustment substances,such as betaine and proline,can be synthesized to resist stress.The previous studies of the subject found that Salinicola tamaricis F01can infect the same salty plant as the new species of endophytic bacteria found in the halophyte,indicating the diversity of interaction with plants-endophytic bacteria in the same habitat.Therefore,based on the inter-relationship between plant-endophyte in the saline-alkali soil of the Yellow River Delta,the paper provides new insight into the role of halophyte-endophytic symbiosis in plant salt tolerance.The research content of the topic mainly includes:?1?Colonization of Salinicola tamaricis F01 in Suaeda salsaThe plant endophyte Salinicola tamaricis F01,a Gram-negative bacteria,has a rod-like shape and does not produce spores.It is a halophilic bacteria,a new species of the Salinicola genus,separated from the halophyte Tamarix.It can produce guanidine acetate,ferritin and ACC deaminase.At the same time,it can resist a variety of heavy metals,especially manganese.It plays an importent role in promoting the ability of parasitic plants in resisting stress.Because of the symbiotic relationship between plant endophytes and plants,endophytes are more beneficial to exert their biological function in the stable internal environment of plants^[3,4].Studies have shown that the colonization,time and location of endophytic bacteria in plants are closely related to their ability^[5].We transferred F01^T,isolated from Tamarix chinensis,to the interior of the halophyte in the same habitat,to label F01^T by fluorescent labeling,and transfer F01^T into Suaeda salsa by watering root method.Under the fluorescence microscope,it was found that it is different in the roots,stems and leaves,mainly colonized in the stems,followed by the root and finally the leaves.By understanding the colonization sites,it will provide the theoretical basis to further develop endophytic bacteria.In view of the advantages in the quantity and variety of the salt-tolerant bacteria of Suaeda salsa,combined with the laboratory's macrogenomic sequencing of endophytes of Suaeda salsa,more salt-tolerant and halophilic bacteria were detected.No found the presence of Salinicola tamaricis F01.It is especially important to improve the soil resistance of saline-alkali soil by improving the anti-reverse characteristics of the alkali-salt by the endophytes-plants interaction.?2?Physiological and biochemical effects of Salinicola tamaricis F01 on Suaeda salsa under salt stressIn order to further study the relationship between microorganisms and hosts,the paper conducted an in-depth analysis of the physiological and biochemical effects of Salinicola tamaricis F01 in Suaeda salsa,in order to study the relationship between endophytes and hosts.F01^T is a moderate endogenous halophilic bacteria,isolated and preserved in our lab.Previous studies have classified it as a new species of the Salinicola genus.At present,there is no report on its interaction with Suaeda salsa and the physiological and biochemical effects by promoting anti-reverse function to Suaeda salsa.According to the known literature,under salt stress,Suaeda salsa can change its internal metabolism and produce a large number of osmotic adjustment substances to improve the stress environment.In this experiment,the salt parameters were set to0,200,300,400,500,600,700,800 mM,and the control was set to detect the plant height,root length,dry weight,fresh weight,chlorophyll,soluble protein,soluble sugar,malondialdehyde and betaine,proline content,antioxidant enzyme system to verify the physiological and biochemical effects of F01^T on Suaeda salsa under salt stress.The results showed that under salt stress,endophytic F01^T could regulate the plant height,root length,fresh weight,dry weight and chlorophyll content of Suaeda salsa,and it had a positive effect.Under the measurement of physiological indicators,it was found that endophytic bacteria F01^T contributes to the accumulation of osmotic adjustment substances.By measuring SOD,POD,CAT antioxidant enzymes,it can be seen that endophytic F01^T can significantly improve the ability of Suaeda salsa to resist high salt stress.Generally,Suaeda salsa containing F01^T was significantly optimized in various physiological and biochemical indexes compared with the control.Especially after 600 mM,the physiological indices tend to be obvious with the increase of salt concentration.It may be related that the optimum growth salt concentration of F01^T is about 800 mM.?3?Transcriptome analysis of Suaeda salsa under the conditions of endophytic bacteriaBased on the above-mentioned salt stress,the effect of F01^T on the physiological and biochemical functions of Suaeda salsa.In this paper,plants which are infected stabilly by F01^T through transcriptome sequencing and mRNA expression profile.The results of differential expression analysis indicated that after colonization by F01^T,there were 215 upregulated genes and 336 downregulated genes,which involved limonene,terpene and aminobenzoate degradation pathway,and found beta-like protein 3 transduced 40s and 60s ribosomal subunits and serine/threonine-protein kinase At5g41260 transduced phytohormone signal.?-transduction protein 3 plays a key regulatory role in signal transduction,cell proliferation,apoptosis and other processes.Serine/threonine-protein kinase At5g41260 plays an important role in plants when they are stimulated by different stimuli such as pathogenic bacteria,osmotic stress and high salt stress.In this experiment,F01^T effects on the physiological and biochemical change of Suaeda salsa were verified by RNA-seq.In the differentially annotated genes,unknown protein LOC104904366 and LOC104908935 were found to be significant and further research is needed.This result facilitates further analysis of the molecular mechanisms by which plants interact with microorganisms.