Regulation Of Exogenous GABA On Plant Root Growth And Hypoxia Stress

The root system is one of the most important vegetative organs of plants,but it often suffers from various stresses during growth and development.It is necessary for crop production to improve the growth state of the root system and the resistance of the root system to adversity.Hypoxia is one of the main stresses suffered by plant roots.Hypoxia stress firstly caused the respiratory metabolism of plant roots to be blocked,which in turn caused a series of metabolic disorders.The ?-aminobutyric acid(GABA)anabolic pathway is the main branch of plant respiration.GABA can quickly accumulate in plants in response to hypoxia stress and has a mitigating effect on hypoxia stress.Studies have shown that exogenous GABA can regulate plant root growth,and cause endogenous GABA accumulation to relieve hypoxic stress and increase plant hypoxia tolerance.GABA can also regulate plant endogenous hormone levels,but whether GABA can regulate plant root growth and hypoxia tolerance by regulating endogenous hormone levels has not been reported.In this study,using wild-type Arabidopsis and related mutants as materials,using real-time fluorescent quantitative PCR,GUS staining,high performance liquid chromatography and other techniques,we studied the regulation of GABA through endogenous hormone levels to regulate plant root growth and resistance to hypoxia stress The mechanism,at the same time,using walnut tree as a material,using biostatistics,micro-methods and photosynthesis detection technology to conduct GABA in practical application research.The main findings are as follows:1.Exogenous GABA can regulate the growth and structure of Arabidopsis roots.Under normoxic conditions,low concentration GABA treatment can promote the growth of the main root of wild-type Arabidopsis thaliana and inhibit the number of lateral roots.However,the root growth after the POP2-1 gene mutation is contrary to the above trend,and high concentration GABA also inhibits the root length.The results of GABA content detection found that both POP2-1 mutation and exogenous GABA will increase the endogenous GABA content,indicating that exogenous GABA treatment can increase the endogenous GABA content,thereby regulating the growth and structure formation of Arabidopsis roots;under low oxygen conditions,Exogenous GABA treatment can reduce the inhibition of Arabidopsis root growth by hypoxia stress,indicating that exogenous GABA can alleviate the damage of hypoxia stress to plant root growth.2.GABA can regulate Arabidopsis root hormone levels by regulating the expression of auxin synthesis transport genes and cytokinin synthesis genes,but there may be different regulatory mechanisms under normoxic and hypoxic conditions.Under normoxic conditions,GABA can upregulate the expression of auxin synthesis genes and downregulate the expression of auxin transporter genes,thereby increasing the auxin accumulation of Arabidopsis root tips,and at the same time causing the upregulation of cytokinin synthesis genes and metabolic genes,which may cause Cytokinin accumulation inhibits the inhibition of auxin on root elongation;under hypoxic conditions,GABA treatment has no obvious effect on root auxin content,but it can upregulate the expression of auxin synthesis and transport genes,and upregulate cytokinin metabolism.Gene expression,so GABA may promote root elongation mainly by releasing cytokinin's inhibition of main root elongation.3.Exogenous GABA can effectively improve the growth status of the above-ground and underground parts of Sorbus chinensis and enhance the anti-hypoxic capacity of Sorbus chinensis,and has certain application value.Exogenous GABA can increase the amount of root generation and new root length of Walnut tree under normal growth conditions,and promote the increase of leaf area;it can also slow down the inhibitory effect of hypoxia stress on the photosynthetic rate of Walnut tree and increase the anaerobic respiration enzymes of the root system Live,improve the tolerance of the root system of Sorbus chinensis to hypoxia;indicating that GABA can improve the growth status of Sorbus chinensis and improve the ability to resist hypoxia.This article explores the effects of exogenous GABA on Arabidopsis root growth and resistance to hypoxic stress,including endogenous GABA levels,endogenous hormone levels and related gene expression regulation,in order to further study GABA on plant root growth and anti-hypoxia regulation The mechanism research provides reference.At the same time,it also proves that GABA has certain application value in improving the growth of Sorbus chinensis and resisting hypoxia stress.