The Landscape Genomics And Transcriptome In Response To Drought Of Pterocarya Stenoptera

Pterocarya stenoptera C.DC(Juglandaceae)is a common deciduous broad-leaved tree species in China.In this study,the widely distributed Pterocarya stenoptera in China was used as the research object to study the adaptive genetic differentiation of Pterocarya stenopteraand its drought response and adaptive genes based on landscape genomics.In this study,9 SCoT primers were used to analyze the genetic structure of 510 samples from 22 wild Pterocarya stenoptera populations in order to reveal the complex interaction between environmental variables and adaptive genetic differentiation.Bayesian population structure analysis shows that 22 Pterocarya stenoptera populations are divided into two genetic groups;RDA analysis shows that the formation of the population structure is caused by different choices of environmental differences;Arlequin’s layered island model and BayeScan method combined,A total of 44 anomalous sites were identified,43 of which were environment-related sites;LFMM latent factor mixed model analysis showed that among 25 environmental variables,solar radiation in June(Sr6)and the lowest temperature in the coldest month(Bio6),temperature seasonality(Bio4)and water vapor pressure(Wvp1)in January have the largest number of environmentally relevant sites,of which Sr6 is related to the ecological habits of "popular sunshine" of Pterocarya stenopterar,and Bio6 and Wvp1 are associated with Ecological habits.It is concluded from this that different choices of environmental differences play a major role in the genetic differentiation of Pterocarya stenoptera,At the same time,Sr6,Bio6,Bio4,and Wvp1,which are environmental variables related to the ecological habits of Pterocarya stenopterar,play a key role in driving the adaptive evolution of species genomes.Pterocarya stenoptera is mainly distributed on both sides of streams or in wetlands in nature.At present,Pterocarya stenoptera has been widely used in urban greening,but under its greening cultivation environment,the rainfall is far less than it has more water supply in the natural environment.Therefore,drought is the main stress factor facing the growth of Pterocarya stenoptera in the city.In this study,the physiological mechanism,transcriptome sequencing,and reanalysis of previous landscape genomics research results were used to further explore the adaptation mechanism of Pterocarya stenoptera under drought stress.The results showed that short-term drought stress severely damaged the cell membrane system of Pterocarya stenoptera;Pterocarya stenoptera initiated a series of procedures to cope with short-term drought stress,including stomatal closure,root expansion,increased root water absorption,improved cell membrane fluidity,removal of active oxygen and Increase the osmotic pressure of the cell;Pterocarya stenoptera adapts to the long-term drought stress by regulating the thickness of the cell wall and the upper or lower expression limit of downstream genes in the hormone signaling pathway.More importantly,the results clearly support the hypothesis that the number of environmental response genes(ERGs)that deal with short-term environmental stress is much greater than the environmental adaptation genes(EAGs)that deal with long-term stress.EAGs are not necessarily ERGs.This study provides new insights into the adaptation mechanisms of plants to short-term and long-term drought stress.