Functional Analysis Of Poplar Aquaporin Gene PagPIP1;3 Under Drought Stress

Drought is one of the most common and the first harmful environmental stress factors to plants.Breaking through the limitation of drought conditions on poplar is an urgent need for efficient breeding of poplar drought resistance varieties and poplar development.Plasma membrane intrinsic proteins(PIPs)played an important role in plants under drought stress.According to the bioinformatics analysis and the expression characteristics of PIP1s family under drought stress,the key PIP1s gene which involved in drought stress of poplar was identified.The overexpressed lines were obtained by agrobacterium transformation method,and the function of the overexpressed lines in drought stress were explored from the morphological and physiological aspects.The main results are as follows:1.In this study,five PIP1s subfamily genes of poplar were obtained from the poplar whole genome database.The structure,protein physical and chemical properties,transmembrane structure prediction and conservative motif of the five genes were analyzed by bioinformatics methods.The results showed that poplar PIP1s had high conservatism.2.The key gene PagPIP1;3 involved in poplar drought stress was identified from poplar PIP1s by the tissue-specific expression analysis of PIP1s and the results of bioinformatics.PagPIP1;3 was cloned from 84K poplar and successfully introduced into Yinzhong poplar.Eight overexpressed PagPIP1;3 lines were successfully identified.3.After drought treatment for fifteen days,the morphological and physiological levels of two overexpression lines of PagPIP1;3(OE1,OE2)and wild-type lines(WT)were measured.Under drought stress,PagPIP1;3 overexpression inhibited the transpiration and enhanced the instantaneous water use efficiency(WUE_i)of Yinzhong poplar.The growth of transgenic lines was significantly better than that of WT.4.Under drought,the results of biomass and relative water content of overexpressed lines revealed that PagPIP1;3 overexpression increased the drought tolerance of poplar by enhancing the capacity of water transport,water retention and biomass accumulation.5.Different overexpressing PagPIP1;3 lines showed expression advantages in different tissues.In leaves,OE2>OE1>WT;in roots,OE1>OE2>WT.MDA content of OE2 was lower than that of WT.Thus,overexpressing PagPIP1;3 enhanced the drought resistance by improving the protective effect on biofilm,WUE_iand expression of poplar under drought.