The Functional Analysis Of Cassava Ferritin Gene

Cassava?Manihot esculenta Crantz?,a plant of the Manihot,is very important economic plant,which mainly grown in tropical and subtropical regions.Cassava has the high resistance to high temperature and infertility but has sensitivity to low temperature.It has significance value to study the cold resistance mechanism of cassava in improving the cold resistance and expanding the planting area of cassava.Ferritin is recognized in resisting multiple stress and improving the iron content in plant.It's possible to improve the cold stress resistance and to increase the iron content in cassava.This study analyzed the transcriptional changes between the diploid and its tetraploid cultivar of South-China 8?SC8?using the technique of RNA-seq and found the transcriptional change of gene of Ferritin in cassava.We cloned the Ferritin gene and gave the name of MeFer.After transferred the overexpressed gene?with the 35s promoter of CVS?to sweet potato cultivar of Ayamurasaki,we studied the function of MeFer in cold resistanc.The results are as follow.In this paper,we used the RNAseq technique to analyze the transcriptome discrepancy between the cassava diploid?2SC8?and tetraploid?4SC8?plants of South China which are under low temperature stress,and optimized the transformation system of sweet potato and cassava to improve the genetic transformation of the cassava ferritin gene.The main findings are as follows:1.High-throughput RNA-seq was used to study the genome-wide transcription profiles between diploid cultivar and it's tetraploid cultivar of South China 8Cassava?2-SC8 and 4-SC8?.We found that several biological processes participate in the response of cassava to low temperature stress,including osmotic regulatory substances,active oxygen clearance,membrane lipid structure changes,hormone metabolism and signal transduction and gene expression regulation involving transcription factors.A number of genes have been screened that may improve the cold resistance of cassava.2.We cloned the gene of MeFer from cassava for the first time.This gene is induced by low temperature stress and it's encoded protein has a conserved domain like that in Ferritin gene family.It might be taken part in the responses in cold stess and mutiple abiotic stresses.3.We optimized the regeneration system cassava cultivar of TMS60444?C3?.We found that the CIM medium adding picloram of 8 mg/L was the best medium in somatic embryo induction,and the medium of GD with picloram of 10 mg/L was the best brittle embryo callus proliferation medium.4.We got 22 lines of overexpressed MeFer of Aya.Some of them had the elevated cold resistance.The improving trend of H₂O₂ and MDA content were decreased under cold stress and the activities of some antioxidant of SOD,CAT and POD were not changed obviously.Thus indicated that it's possible that other antioxidant pathway might be induced by MeFer in cold resistance.