Studies On Transient Genetic Transformation And Drought Resistance Of LoMYB8 Genes In Larix Olgensis

Larix olgensis is the main afforestation tree species in Northeast China,it has the characteristics of fast growth,good ecological benefit and high technological value and it's widely used in barren mountain afforestation and pulp forest construction.The conventional breeding cycle is long,but the excellent plants can be obtained quickly by transgenic means to meet the needs of the market.The regulation of gene spatio-temporal expression by transcription factors at the transcription level affects the growth and development of plants and the ability to resist stress.As a large family of transcription factors in plants,MYB and NAC are mainly involved in primary and secondary metabolic reactions,plant growth and development,cell morphology and pattern building,response to biological and abiotic stresses,and so on.In this paper,Larix olgensis was used as experimental material to study whether genes were involved in drought resistance through instantaneous genetic transformation.the main conclusions were as follows:1.The full-length LoMYB8,LoMYB9 and LoNAC18 of 1121bp,1223bp and 1042bp were cloned from Larix olgensis,and the overexpression and inhibition expression vectors and engineering strains were constructed.2.The transient genetic transformation system of Larix olgensis was constructed,the GUS staining obtained by the transient transformation system and the plants transfected with LoMYB8,LoMYB9 and LoNAC18 genes were used to verify the successful construction of the system.3.Under the condition of drought stress simulated by PEG,LoMYB8 was induced by drought,and the gene expression was significantly up-regulated compared with the control,the changes of physiological indexes showed that the drought resistance of transgenic plants was improved,the results showed that the gene was involved in the response of Larix olgensis to drought stress,but the drought resistance of Larix olgensis plants transformed by LoMYB9 and LoNAC18 was not significantly improved.4.After 48 hours of PEG stress,a total of 29589 annotated unigenes were obtained by sequencing the transcripts of transiently transformed LoMYB8 plants and control plants,the number of differentially expressed genes was 1740 and the number of annotated differentially expressed genes was 1532;the number of differentially annotated genes in KOG,GO and KEGG databases was 905,1227 and 814 respectively.A total of 46 biological functions were enriched in GO classification,and the most differentially metabolized substances were enriched in the biological process;KOG annotations are annotated to 22 functional categories;a total of 98 metabolic pathways were annotated by KEGG metabolic pathways,most of which were related to energy synthesis and metabolic pathways,antioxidant pathways and so on.5.After 48 hours of PEG stress,a total of 460 differential metabolites were obtained in the metabolic group sequencing of transiently transformed LoMYB8 plants and control plants,and 29 differential metabolites were annotated by KEGG,they were annotated in 34 metabolic pathways.The annotated pathways are mainly related to signal transduction,carbohydrate metabolism,amino acid metabolism,flavonoids metabolism and so on.