Identification of the Glyceraldehyde-3-Phosphate Dehydrogenase () Gene Family in Revealing Its Response Characteristics to Low-Temperature and Pathogen Stress.

The glyceraldehyde-3-phosphate dehydrogenase () gene plays a pivotal role in the glycolysis/gluconeogenesis process, contributing significantly to glycosyl donor synthesis, plant growth and development, and stress responses. Bl., a heterotrophic plant in the Orchidaceae family, has its dried tubers used as the traditional Chinese medicine. This study identified three genes in , all encoding basic, stable, hydrophilic proteins. Phylogenetic analysis and subcellular localization predictions categorized as a plastid subtype, while and were classified as cytoplasmic subtypes. Prokaryotic expression experiments demonstrated successful expression of the GeGAPDH1 protein in , which exhibited significant GAPDH enzymatic activity. Subcellular localization experiments showed that GeGAPDH1 was localized in the plastid. Expression analysis indicated that the three genes were predominantly expressed in tubers. Under low-temperature stress, although the total GAPDH enzyme activity in tubers did not change significantly, the expression of was significantly up-regulated, while and were significantly down-regulated. This suggests that different subtypes of may regulate cold resistance through different pathways. Upon pathogen infection, the gene family exhibited pathogen-specific regulatory patterns. During infection by , both the expression levels of all three genes and the total GAPDH enzyme activity in tubers increased significantly; however, infection induced a significant increase in total GAPDH enzyme activity without significant changes in gene expression. These results suggest that the gene family may respond to different pathogen infections through transcriptional or translational regulation mechanisms. This study systematically identified and characterized the gene family in , providing a theoretical foundation for understanding the functional differentiation of in heterotrophic plants.