Effects Of GmPLMT Gene Transfer On Photosynthetic Characteristics And Carbon Metabolism Of Wild And Cultivated Soybean

Cultivated soybean is domesticated by artificial selection and cultivation for a long time.In the process of evolution,there are obvious differences between cultivated soybean and wild soybean in agronomic and physiological and biochemical characteristics,forming a unique adaptation mechanism.It has potential application value in the genetic improvement of soybean functional components.Soybean phosphatidylmethyltransferase（GmPLMT）exists in the pathway of soybean phosphatidylcholine synthesis and is the key enzyme in lecithin synthesis.The change of this gene expression affects lipid metabolism and the transformation between carbohydrates and lipids.In this study,the GmPLMT gene cloned in the laboratory and the plant expression vector constructed were used to carry out the genetic transformation of soybean hairy roots,and the transgenic soybean materials with GmPLMT gene were obtained.The photosynthetic physiological characteristics of wild and cultivated soybean were studied by transferring GmPLMT gene,and the changes of photosynthetic carbon metabolism were analyzed in order to provide theoretical basis for molecular breeding of high phospholipid soybean.1.Effects of transgenic GmPLMT gene on photosynthetic physiological characteristics of wild and cultivated soybeanTransgenic GmPLMT gene promoted the photosynthesis of wild and cultivated soybean.The net photosynthetic rate（P_n）,stomatal conductance（G_s）and transpiration rate（T_r）of GmPLMT transgenic soybean were higher than those of the control,and the wild soybean increased by 72.37%,108.92%and 77.14%respectively;the cultivated soybean increased by19.77%,43.25%and 40.53%respectively;the intercellular CO₂ concentration（C_i）was lower than that of the control;the wild soybean decreased by 9.68%and the cultivated soybean decreased by 3.81%.In addition,the chlorophyll content and Ru BP carboxylase activity of GmPLMT transgenic soybean were higher than those of the control,wild soybean increased by42.79%and 44.54%,cultivated soybean increased by 24.23%and 11.50%respectively.2.Effects of GmPLMT Gene transfer on activities of key enzymes in photosynthetic carbon Metabolism of Wild and cultivated SoybeanGmPLMT gene transfer increased the activities of key enzymes in carbon metabolism of wild and cultivated soybean.Compared with the control,the activities of sucrose phosphate synthase（SS）,sucrose synthase（SPS）,starch synthase（SSS）,ADPG pyrophosphorylase（ADPG-Ppase）and UDPG pyrophosphorylase（UDPG-Ppase）in GmPLMT transgenic wild soybean increased by 61.69%,21.00%,28.25%,94.99%and 133.80%,respectively.Cultivated soybean increased by 36.44%,40.60%,20.00%,56.76%and 83.95%,respectively.On the whole,the activity of key enzymes in carbon metabolism of wild soybean was higher than that of cultivated soybean.3.Effects of GmPLMT Gene transfer on photosynthetic products of Wild and cultivated SoybeanThe contents of photosynthetic carbon metabolites in GmPLMT transgenic wild soybean and cultivated soybean were significantly increased.The contents of soluble sugar,soluble protein,sucrose,starch and free amino acids in GmPLMT transgenic wild soybean leaves increased by 73.12%,31,96%,50.51%,28.25%and 91.79%,respectively,and the hairy roots increased by 66.67%,31.77%,36.12%,32.02%and 184.42%,respectively.The contents of soluble sugar,soluble protein,sucrose,starch and free amino acids in transgenic soybean leaves increased by 51.46%,29.84%,16.05%,20.00%and 53.78%respectively compared with the control;the hairy roots increased by 230.97%,66.13%,17.71%,78.52%and 257.03%,respectively.On the whole,the change of substance content of wild soybean in leaves was greater than that of cultivated soybean,and the increase of cultivated soybean in hairy root was higher than that of wild soybean.4.Correlation Analysis between activities of key enzymes of carbon Metabolism and photosynthetic parameters and carbon metabolites in transgenic Wild,cultivated and non-transgenic Soybean with GmPLMT GeneP_n,G_sand C_iof GmPLMT transgenic soybean were positively correlated with SS,SPS,SSS,ADPG-Ppase and UDPG-Ppase,while non-GM soybean C_i was positively correlated with SS,SPS,SSS,ADPG-Ppase and UDPG-Ppase,while P_n,G_s and T_r were negatively correlated with SS,SPS,SSS,ADPG-Ppase and UDPG-Ppase.The activities and products of key enzymes of carbon metabolism in GmPLMT transgenic soybean leaves were positively correlated,and the correlations among other indexes were very significant except soluble protein.In non-transgenic soybean,the contents of sucrose and soluble sugar were positively correlated with the activities of key enzymes of carbon metabolism,the contents of starch and soluble sugar were significantly correlated with SS and SSS,and the content of soluble protein was negatively correlated with the activities of key enzymes of carbon metabolism.