Transcriptome,Physiological And Biochemical Analysis Of Two Potato(Solanum Tuberosum L.)Clones Under Drought Stress

Roots provide important materials for the growth and development of plants such as water,minerals and inorganic salt ions.The changes of root micro-structure,physiological and biochemical and molecular level of genes plays an important role under drought stress.In this study,two drought-tolerant varieties(C16: CIP397077.16 and C119: CIP398098.119)with the same growth tolerance were selected from the resources introduced by the International POTATO CENTER(CIP).The tube culture pattern and laboratory tissue culture method without limiting root growth were used to systematically analyze the changes in the genes of external morphological characteristics,resistance biochemical indicators,apical microscopic and ultrastructural and molecular levels under different drought stresses.The results show:1.Drought stress can significantly increase root length,root activity,catalase activity,soluble sugar proline content,and significantly decrease plant height,angle between leaf and stem,relative water content of root system,and striking change of structure and cell wall integrity of root apex,which indicates that tubular cultivation model is ideal for potato root system to respond to drought stress.2.Compared with C16,most of the above indicators of C119 showed significant advantages under normal irrigation and different level of water treatments,and showed better adaptability to drought stress.In addition,under drought stress,the xylem vessel diameter of two potato varieties decreased,and the number of xylem vessel of C 119 with stronger drought resistance was significantly less than that of C16,which indicated that potato could also resist drought stress by changing the structure of water transport.3.The results of transcriptome sequencing showed that 78 differentially expressed genes were up-regulated and 51 down-regulated genes were down-regulated in C119 compared with C16 at 0 h stress.With the increase of stress time,the number of up-regulated differentially expressed genes in C119 was 38,322 and 182 respectively and down-regulated genes were 21,77 and 102 respectively compared with that in C16 at 2h,6h,12 h and 24 h of continuous stress.However,78 genes were up-regulated and 18 genes down-regulated after 2 hours of stress until the end of stress treatment 24 hours later.Most of the up-regulated genes are related to ion binding,oxidoreductase activity and carbohydrate metabolism pathway.The down-regulated genes are related to thylakoid membrane formation,cell wall synthesis and steroid biosynthesis,which suggested that these genes may be involved in the regulation of metabolic pathways in potatoes in order to prevent the damage caused by stress environment.