Analysis Of Stress Resistance Function Of LpNAC6 Gene And Optimization Of Genetic Transformation System In Lilium Pumilum

Lilium pumilum has not only high ornamental value,but also strong stress resistance,so it is an important parent for lily resistance breeding.NAC transcription factors are a class of specific transcription factors with a variety of biological functions in plants.They are involved in plant growth and development,and in response to biotic and abiotic stresses,and become potential candidate genes for enhancing plant stress tolerance.In this study,the LpNAC6 gene transgenic tobaccos were treated with alkali and drought stress.The role of LpNAC6 in plants response to abiotic stress was studied by studying seeds germination,seedlings fresh weight and phenotype and physiological index determination of adult seedlings growth,etc.,and the genetic transformation system of L.pumilum was improved by screening suitable kanamycin concentration and pre-culture time,etc..The main research results are as follows:1.LpNAC6 enhanced the alkali resistance of transgenic tobacco.The seeds,seedlings and adult seedlings of transgenic tobacco LpNAC6 were treated with alkaline stress.Compared with the wild type,the germination rate,fresh weight and root length of the transgenic tobacco were inhibited less,and the alkaline tolerance was enhanced.The growth of transgenic tobacco adult seedlings was better than that of wild type.The activities of antioxidant enzymes(SOD,POD,CAT),chlorophyll content,Pro content,and photosynthetic capacity were significantly higher than those of wild type,and the contents of MDA,H2O2 and O2-were significantly lower than those of wild type.The expression levels of stress-related genes in transgenic tobacco were significantly increased,and the alkaline tolerance was enhanced.LpNAC6 plays a positive regulatory role in plant alkali tolerance.2.LpNAC6 reduced the drought resistance of transgenic tobacco.The seeds,seedlings and adult seedlings of transgenic tobacco LpNAC6 were treated with drought stress.Compared with the wild type,the germination rate,fresh weight and root length of transgenic tobacco were inhibited more significantly,and the drought resistance was reduced.The growth of transgenic tobacco seedlings was lower than that of wild type.The activities of antioxidant enzymes(SOD,POD,CAT),chlorophyll content,Pro content and photosynthetic capacity were significantly lower than those of wild type,and the contents of MDA,H2O2 and O2-were significantly higher than those of wild type.The expression levels of stress-related genes in transgenic tobacco were significantly decreased,and the drought resistance was reduced.LpNAC6 plays a negative regulatory role in plant drought stress.3.Transgenic tobacco with LpNAC6 had higher sensitivity to ABA.The germination rate transgenic tobacco seeds,fresh weight and root length of transgenic seedlings under ABA stress were significantly lower than those of wild type.LpNAC6 may negatively regulate tobacco drought resistance by regulating some ABA responsive genes through ABA dependent pathway.4.The genetic transformation system of L.pumilum was optimized and LpNAC6 gene was transferred into L.pumilum.The scale of L.pumilum was used as the transformation receptor.The screening concentration of kanamycin(Kana)was 120 mg/L,the pre-culture time was 3 days,the concentration of Agrobacterium solution OD600 was 0.7,the concentration of acetosyringone(AS)was 20 mg/L,and the infection time was 15 min.Overexpression of LpNAC6 transgenic L.pumilum were successfully obtained through this genetic transformation system.