互叶白千层茎尖响应超低温保存过程转录组分析OA

In order to elucidate molecular response mechanisms of Melaleuca alternifolia shoot tips during dif-ferent stages of vitrification cryopreservation,high-throughput sequencing was performed for transcriptome se-quencing of shoot tips at four key stages,including before freezing(A1),after preculture(A2),after dehydration(A3)and 48 h of cryopreservation(A4).A total of 74.92 Gb of Clean data and 503 147 794 high-quality Clean reads were obtained,with approximately 84.86%Clean data successfully mapped to reference genome,of which 78.05%Clean data were mapped to exonic regions.In A2 vs A1,A3 vs A1,A4 vs A1,A3 vs A2,A4 vs A2 and A4 vs A3,6 753,7 373,6 853,4 343,4 337 and 615 differentially expressed genes(DEGs)were identified re-spectively.Compared with before freezing,the highest number of DEGs was detected during dehydration process,whereas significantly decreased in DEGs was dected after dehydration.NAC,AP2/ERF-ERF,MYB-related,C2H2 and WRKY were identified as core transcription factor families.Gene Ontology(GO)functional enrich-ment analysis revealed that DEGs were mainly enriched in terms related to response to oxygen-containing com-pounds,response to abiotic stress and response to water deprivation.Kyoto Encyclopedia of Genes and Ge-nomes(KEGG)pathway enrichment analysis revealed that DEGs were mainly enriched in pathways related to metabolism,biosynthesis of secondary metabolites,plant hormone signal transduction and MAPK signaling.Core mechanisms underlying response of M.alternifolia shoot tips to cryopreservation stress included oxidative defense,osmotic regulation,MAPK signaling transduction,plant hormone signal transduction,biosynthesis of secondary metabolites,metabolism,phenylpropanoid biosynthesis and diterpenoid biosynthesis.Dehydration might represent critical stage causing cellular damage during cryopreservation of M.alternifolia shoot tips;after dehydration,expression patterns of stress responsive genes were essentially established,and cells entered rela-tively stable state.