Transcriptome Analysis Under Cold Stress And Function Identification Of SwDREB1B In Cold Induction From Sweet Potato(Ipomoea Bataasa)

Sweetpotato(Ipomoea batatas(L.) Lam.) is the world’s fourth important food crops. The tuberous roots of sweet potato are usually as staple food,also industrial material. The sorage toot of sweet potato are sensitives to chilling injury(CI) during postharvest storage. There are not sufficient transcriptomic and genomic in public databases for understanding of the molecular mechanism underlying the chilling. Thus, high throughput transcriptome sequencing is needed to generate enormous transcript sequences from sorage toot of sweet potato under low-temperature.In this study,we cloned and characterized two novel gene encoding DREB1/CBF and DREB2,named Sw DREB1 B and Sw DREB2, meanwhile, we also considered the relationship of Sw DREB1 B and antoxidant genes. The results are as following:(1)We obtained 8.25 Gb use data and 40.86 million clean reads. De novo assembly yielded 201,388 Transcripts and 60,170 unigenes with an average length 1352.32 bp,781.90 bp. The N50 length 2035 bp,1455 bp.(2)Based on sequence similarity search with know protein, a total of 34,168 unigenes were identified. Out of these annotated unigenes, 22,723 unigenes were assigned to gene ontology. Searching against the Kyoto Encyclopedia of Gene Ptahway database(KEGG) indicated that 7,437 unigenes were mapped to 148 KEGG pathways. In addition, 16 unigenes were annotated DREB transcription factors family. 26,002 unigenes weren’t annotated public database, the specially genes of sweet potato may be contained in it.(3)In low-temperature stress condition, though compare witrh the control group and experiment group, 4,470 unigenes were identified as different expression gene, 4,059 unigenes up-regulated expression, 411 unigenes down-regulated expression.(4)We obtained two DREB transcription factors use PCR technology: Sw DREB1 B and Sw DREB2. The open reading frame of Sw DREB1 B is 711 bp, encoding 237 amino acids, contain a highly conserved AP2 domain, no intro. The amino acids analysis and phylogenic analysis confirmed that Sw DREB1 B belongs to the 1B subgroup of DREB subfamily. The Sw DREB2 open reading frame was 726 bp, encoding 242 amino acids, contain a AP2 domain,the analysis of amino acid and phylogenic indicated that it’s belong to the 2 subgroup of DREB supfamily.(5)The expression patterns of Sw DREB1 B by q RT-PCR. The result indicated that Sw DREB1 B had no tissue-specific expression characterstics. It’s up- regulated expression by low-temperature. At low temperature, the Sw DREB1 B has positive correlation with various antioxidant enzymes activity. The expression of almost all the antioxidant genes induced under low temperature treatments occurred in storage root and leaves, with the exception CAT gene, it’s down- regulated in leave.