Research On Air Humidity Stress And Cloning Of Related Gene PsTHi4 In Pterocarya Stenoptera

Pterocarya stenoptera is a perennial deciduous broad-leaved tree.P.stenoptera is distributed in North China,South China and Southwest China,and is most common in the Yangtze River basin and Huaihe River basin.P.stenoptera not only has the greening function,but also has the unique ecological function and the medical value.Due to its excellent ornamental value,it has been widely used in the city greening in recent years,mainly for the planting of street trees and park ornamental trees.In this study,P.stenoptera was selected as the object of study,and the leaf yellow-out occurred when it was planted as a street tree.The dry air humidity stress was studied,and the differences in physiological indexes and transcriptome expression were analyzed.In this study,P.stenoptera seedlings were selected for the dry air humidity stress experiment,with simulated natural air humidity 75%as the control group and simulated air humidity 60%in northern Chinese cities as the experimental group.Physiological indexes were measured at 1,2,3 and 4 weeks of stress,and transcriptome sequencing was performed at 2 and 4 weeks.Physiological indexes showed:Pro content did not change,SOD activity of each time to simulate the natural air humidity(75%humidity)were higher than northern Chinese city air humidity(60%humidity),POD results rose at first and lowered later,significant difference was found in the experimental group and control group,shows that under dry air humidity stress,P.stenoptera had osmotic regulation.Transcriptome sequencing showed that 289 differentially expressed genes were identified at 2 week,150 genes were up-regulated and 139 genes were down-regulated.At week 4,247 differentially expressed genes were identified,94 genes were up-regulated and 153 genes were down-regulated.GO enrichment analysis showed that these differentially expressed genes were mainly concentrated in the metabolic process.KEGG database showed that under dry air stress,157 and 185 differentially expressed genes were annotated into the KEGG pathway at the 2 and 4 week,significantly enriched in the thiamine metabolism pathway respectively.In this study,PSTHi4 gene was successfully cloned,and its physicochemical properties,secondary structure,hydrophilicity and hydrophobicity were analyzed.The predicted location of PSTHi4 gene was in chloroplast.This study provided an important basis for understanding the adaptation mechanism of P.stenoptera to dry air humidity stress,and for the cultivation and management of P.stenoptera in northern China.The successful cloning and protein analysis of PSTHi4 gene provided the basis for the follow-up research in the laboratory.