3种兜兰FAD2基因克隆及响应零上低温表达的差异分析OA

Low temperature is a critical environmental factor limiting the survival and reproduction of Paphiopedilum species.Fatty acid desaturase 2(FAD2)plays a pivotal role in plant chilling tolerance by dynamically regulating the unsaturation of membrane lipids.Here,the sequence characteristics of FAD2 genes and their expression regulation under low-temperature conditions were systematically elucidated in three Paphiopedilum species with distinct ecological adaptations(P.purpuratum,P.dianthum,and P.armeniacum)through gene cloning,bioinformatics analysis,and qRT-PCR methods.The results revealed that the physicochemical parameters,spatial conformations,and transmembrane characteristics of the three FAD2 proteins were highly conserved.However,their subcellular localization predicted by WoLF PSORT exhibited marked species specificity:PaFAD2 from P.armeniacum showed predominant plastid localization,while PpFAD2 and PdFAD2 exhibited preferential accumulation in the plasma membrane/endoplasmic reticulum and diverse endomembrane systems,respectively.Under 4℃chilling stress,the PaFAD2 gene was rapidly activated at the early stress stage(24 h treatment group)and maintained high expression levels;whereas,PpFAD2 or PdFAD2 genes displayed delayed response or weak induction characteristics,respectively.Integrating biogeographical distribution patterns,it was hypothesized that the rapid transcriptional response of PaFAD2 in P.armeniacum might be evolutionarily associated with long-term adaptation to high-altitude habitats,whereas P.purpuratum and P.dianthum appeared to utilize differential FAD2 expression strategies to achieve an adaptive trade-off between cold resistance and metabolic efficiency.