Functional Analysis Of Some MATE And MYB Genes Highly Expressed In The Arabidopsis Root

Root,an organ for absorbing water and nutrition,plays an important role in the survival of plants in nature.The root has several cell types that form concentric cell layers,which from outside to inside are the epidermis,cortex,endodermis,and the stele.The cortex is least differentiated,and together with the endodermis is called the ground tissue.Currently,it is believed that the function of cortex is storage and wounding repair.However,some studies showed that some genes involved in stress response and transport were specifically expressed in the cortex under different stress treatments,suggesting that,that the cortex may also play a role in stress resistance,transport and other aspects of plant physiology.Therefore,molecular genetic methods were used in this study to explore the unknown functions of the cortex,thereby further understand the root function.First,through analysis of an RNA-seq dataset of various cell types in Arabidopsis root published by others,it is found that many genes are preferentially expressed in the cortex,among which are four MATE and five MYB family genes.In view of the important role of MATE and MYB families in transport and development,we further studied their expression patterns by constructing promoter-GUS transgenic plants and GUS staining.Second,root elongation of mutants for these genes were further measured under different treatments,which are selected according to their expression patterns and bioinformatics analysis of gene chip database.Finally,the function of the target genes was inferred from the mutant phenotype.The main results as followed:1)The gene expression revealed by GUS staining differ from that predicted by the RNA-seq data.No cortex specific expression was observed for any of the selected genes,and the expression patterns are different from each other.Nevertheless,these genes have a high level of expression in cortex,suggesting that the cortex has some functions.2)The expression pattern of DTX36?AT1G11670?,AT2G23690,AT4G33740 and MYB19?AT5G52260?show significant changes under different treatments.DTX36 is probably related to the Na Cl tolerance while MYB19 might be involved in meristem maintenance under high zinc,and AT2G23690 is probably associated with.ROS response caused by heavy metal ions.The root elongation of AT4G33740 mutant b2.1 was decreased significantly under treatment of 1m M Zn Cl₂,100m M Na Cl and 20?M ABA,suggesting that AT4G33740 might be related to stress resistance.3)In addition to the genes described above,bioinformatics analysis also revealed other genes that are highly expressed in the cortex,such as those involved in hormone signaling,stress resistance,and development.The expression pattern and function of these genes will be examined in further studies,which should help elucidate the function of cortex,as they seem to be more specifically expressed in the cortex.