Transcriptome Analysis For Selective Graft Compatibility In Two Persimmon Grafts

Date plum(Diospyros lotus L.)is traditional rootstock in Chinese modern persimmon industry.However,the selective graft compatibility between some persimmon cultivars and Date plum restricted the persimmon industry development.Therefore,understanding the mechanism underlying selective graft compatibility in persimmon will faciliate breeding superior rootstock,which also assist in the healthy development of persimmon industry and rural revitalization.Micrografting technology was employed to build the two kinds of grafts including compatible grafting combination(“Jirou/Date plum”)and the incompatible grafting combination(“Fuyu/Date plum”).Transcriptome sequencing of three parts of different graft combinations of three sampling dates after grafting was performed.Comparative analysis was conducted based on transcriptome to screen genes that influencing graft compatibility.In addition,morphological and histological observations on the graft union were carried out in six grafts,which helps us to explore anatomy and morphological characteristics related to graft compatibility of persimmon.The main results are as following.1.The growth of the compatible graft combination was normal in the early stage after grafting,the content of reactive oxygen species was relatively lower in this grafts.However,regarding to the grafts of incompatible graft combination,some grafts failure occurred gradually in the early stage after grafting and the content of reactive oxygen species was relatively higher.2.The healing status and anatomical observation of micrografts showed that,the healing time of the compatible graft combination “Jirou/Date plum” is shorter.Comparatively,the healing status of the graft union of the compatible graft combination presented more better than that of the incompatible graft combination.Among the compatible graft combinations,Xiaoguo Tianshi autografting can heal regularly,followed by normal growth of graft union on “Jirou/Xiaoguo Tianshi”,“Fuyu/Xiaoguo Tianshi”,“Jirou/Date plum”,and Date plum autografting.The graft union of incompatible graft combination “Fuyu/Date plum” exhibited worse healing status.3.Comparative analysis of the transcriptome in the early grafting stage of “Jirou/Date plum”(compatible graft combination)and “Fuyu/Date plum”(incompatible graft combination)revealed that there were 2,324 genes up-regulated in “Fuyu/Date plum”versus “Jirou/Date plum”.GO terms enriched those genes into the pathway of phenylpropane metabolic process,lignin metabolic process,and oxidoreductase activity.Simutaneously,3,559 down-regulated genes both were enriched into a wider range of biological metabolic processes according to GO enrichment.After a comprehensive analysis,604 genes related to graft compatibility were screened out,those 604 genes were assigned to phenylpropanoid metabolic process,plant hormone signal transduction and starch and sugar metabolismIn conclusion,the content of reactive oxygen species(ROS)was lower in the compatible graft combination at the early stage after micrografting.Genes related to phenylpropane metabolism and plant hormone signaling were highly expressed after grafting,which might promotes graft healing.The content of ROS was relatively higher in the incompatible graft combination,and lower expression of genes related to graft healing was observed.Along with the development of grafts after grafting,the healing of the graft union of the compatible graft combination was more better than that of the incompatible graft combination.