Effects And Changes Of Calcium-Dependent Protein Kinase On The Expansion Of Yam(Dioscorea Opposite Thunb.)Ttubers

In this study,two yam varieties were selected,a local cultivated variety in Inner Mongolia is Bikeqi yam,and Dahechangyu yam introduced from Japan.The aim of this study was to investigate the relationship between the morphological index,physiological index,endogenous hormone content,calcium-dependent protein kinase activity and gene expression levels in two tuber varieties with significant morphological differences between Bikeqi yam and Dahechangyu yam,so as to explore the calcium dependent protein kinase in the process of yam tuber bulking,for yam large-scale production and provide theoretical basis for high quality and high yield.The result of research shows that:(1)During the growth of yam tuber,the morphological indexes of B1 and DHCY yam tuber increased,and the tuber fresh weight,tuber length and tuber diameter increased significantly at the middle stage of tuber enlargement.The inside of the yam tuber starch,total soluble sugar and reducing sugar content in the process of synthesis,transport and accumulation of both has certain correlation,in the process of tuber bulking,reducing sugar and total soluble sugar decomposition into the part used to power the tuber bulking,and the other part is used in the synthesis of starch and stored in the tuber,so yam tuber starch content as a whole is on the rise,and the reducing sugar and total sugar content is on the decline as a whole.(2)IAA,ZR,GA3 and ABA were involved in the formation and expansion of yams tuber.The change trend of IAA and ZR was the same,both of which showed a trend of rising and then falling.By promoting cell division and expansion,IAA and ZR promoted the increase of tuber length and diameter,as well as the consumption of total soluble sugar and reducing sugar and the synthesis of starch.The endogenous hormone GA3 promoted the tuber morphogenesis.Generally speaking,the decrease of GA3 content promoted the expansion of yam tuber.ABA showed a trend of decreasing first and then rising,and the ABA content increased significantly and reached the maximum value at the later stage of tuber enlargement.ABA promoted the maturation of yams tuber.(3)Both the CDPK enzyme activity and the relative expression of CDPK gene showed a trend of rising and then decreasing in the process of tuber swelling,indicating that the expression of CDPK in the tuber swelling stage was proportional to the enzyme activity.The expression of CDPK helps to decompose total soluble sugar and reducing sugar,provides energy for the expansion of yams tubers,and stores starch in yams tubers.CDPK acts as a calcium effector regulating the hormone response,and changes in IAA,ZR,and ABA levels can induce the expression of CDPK enzymes and promote the expansion and growth of tubers.(4)The length of the Chinese yam CDPK gene from the initial codon ATG to the termination codon TAG was 1047bp,encoding 348 amino acids.The CDPK protein molecular formula was C1775H2782N474O515S14,total number of atoms of 5560 and the relative molecular mass is 39451.32,the PI is 5.58,as an acid,to predict the protein for stability,hydrophilic protein,and is a non-transmembrane protein and the protein subcellular localization in the chloroplasts and cytoplasm.The Chinese yam CDPK has a protein kinase domain of 69-81 amino acids.There are three hand calcium ion binding domains,which are 263-275,299-311 and 335-347 amino acids respectively.The secondary structure is mainly composed of the double-helix structure and the irregular coil structure,and can constitute the tertiary structure.