Biological Function Analysis Of SlCAND1 Gene In Tomato(Solanum Lycopersicum)

Ubiquitin-mediated protein degradation pathways are involved in the regulation of plant physiological activities at various stages,including seed development,defense regulation,hormone signal transduction,flower development and photopoiesis.SCF E3 ubiquitin ligase is mainly responsible for target recognition in the way to the substrate,and CAND1 involved in regulating the SCF E3 ubiquitin ligase activity,influencing plant growth and development process,but the specific regulatory mechanism is still not clear.Therefore,the research on the biological functions of CAND1 gene is conducive to the further understanding of the regulatory mechanism of CAND1 gene on plant growth and development.In this study,the expression characteristics of CAND1 gene in tomato were analyzed,and the silenced expression transgenic plants were obtained using RNAi interference technology,and their biological functions and molecular regulatory mechanisms were analyzed.The main research results are as follows:(1)The SlCAND1 gene of tomato was isolated,and analysis showed that the gene contained 29 exons and encoded a polypeptide containing 1229 amino acids.Tomato SlCAND1 and arabidopsis AtCAND1 sequences were analyzed,and they had consistent HEAT repeat and TIP120 domains.The phylogenetic tree was constructed and further analysis showed that the gene was evolutionarily conservative.((2)The quantitative PCR was used to analyze the expression pattern of SlCAND1 gene illustrated,that the expression changes of SlCAND1 in tomato leaves at different development stages and the dynamic expression characteristics in flowers and fruits indicated that this gene had certain regulatory effects on the growth and development of leaves and fruits.(3)The silencing vector of SlCAND1 gene was constructed and tomato explants were transformed into SlCAND1 silencing plants using agrobacterium genetic transformation method.By analyzing the phenotypes of silenced SlCAND1 plants,it was found that there were remarkable divergences between the silenced SlCAND1 plants and wild-type.(4)The silenced SlCAND1 transgenic plants showed plant dwarfing,early flowering and fruit ripening.And the detection found that the related genes regulating GAs and auxin signaling pathway were changed,indicating that SlCAND1 gene may regulate the growth and development of plants mainly by regulating the signal transduction pathways of GAs and auxin and other plant hormones.(5)Treatment of silenced SlCAND1 plants and wild-type seedlings with GAs and IAA at distrinct concentrations.The results showed that both GAs and IAA could restore the root phenotype of transgenic seedlings to normal,suggesting that SlCAND1 may affect the growth and development of tomato roots by regulating GAs and IAA.(6)SlCAND1 transgenic seeds showed low germination rate and slow germination rate during germination.Real-time fluorescence quantitative PCR results showed that the expression level of GAs receptor GID1 was down-regulated,indicating that SlCAND1 may negatively regulate GAs signal pathway to affect seed germination.The above conclusions illustrated that SlCAND1 played an indispensable effect in the height,root morphological development,seed germination,the development of flowers and fruits of tomato plants,and had important biological significance in revealing the molecular mechanism of GAs and other hormones in regulating plant dwarfing,seed germination,root morphological changes,the development of flowers and fruits.