The Role Of AtRNP1 In Plant Drought Stress Tolerance

Drought is always an important threat to the plants' development.Plants will conduct a series of reactions to tolerate the drought condition,such as changing the phenotype of leaves,accumulating high osmotic substances,closing the stomata.hnRNP(heterogeneous nuclear ribonucleoprotein)is a considerable family of RNA binding Protein,and play an important role in the tolerance of plants to the drought condition.The function of ribonucleoprotein 1(RNP1),as a major sub-family of hnRNPs,is still unclear in plants.We use the qRT-PCR to check the expression level and distribution of AtRNP1,the result indicate its wide spread in all tissues of Arabidopsis,major in mature tissues.,and the rising expression level of AtRNP1 with the presence of drought,osmotic stress and ABA treatment,while the salt stress will not impact the expression level of AtRNP1.To explore the duty of AtRNP1,the ribonucleoprotein 1 in Arabidopsis,we construct multiple lines of different AtRNP1 expression level and discover the overexpression lines' sensitive to the drought treatment while the down-regulation lines show no significance.Further works show the defect in root architecture of AtRNP1 overexpression lines during drought stress and the alteration in the size and number of the stomata.The unchanged survival rate of AtRNP1 ? M9c(the mutant AtRNP1 without M9 domain and several C-Terminate amino acids)overexpression lines indicates the importance of M9 domain in AtRNP1.We also understand the defect of the metabolism of Proline,leading to the reduced level of free proline in plants.With the graft experiments,we confirm the reduced level of free proline is the main reason that induces the sensitive of the AtRNP1 overexpression lines to the drought conditions,the defect in root architecture also contributes to the AtRNP1 overexpression lines' susceptible to the drought.Because of the low level of free proline in plants,AtRNP1 overexpression lines are sensitive to multiple kinds of stresses or treatments,including the salt stress,osmotic stress and the ABA treatment.The shortage of water uptake enhance the overexpression lines' sensitivity.Whether more pathways taking part in the interaction needs more work.AtRNP1 shows the influence to the subcellular location of the total mRNA in plants,cells,while the mechanism is still unknown.How this changing of total mRNA's subcellular location influence the Plant-Stress Interaction need further work.This thesis reveals the function of AtRNP1 in Plants' drought stress tolerance,and proves theoretical basis for agricultural application.