Abstract
Banana (Musa spp.) is susceptible to low-temperature stress and other environmental stresses, which can hinder the growth and development. Succinic semialdehyde dehydrogenase (SSADH) is critical for GABA biosynthesis and plays a crucial role in plants. However, the SSADH genes of bananas have not been studied. This study found 19 MaSSADHs, 18 MbSSADHs, and 18 MiSSADHs from the banana genome. According to the phylogenetic tree, these genes can be categorized into five branches. This study cloned the MaSSADH1-14 from banana. The subcellular localization assays of MaSSADH1-14 in tobacco leaves confirmed that the presence of SSADH was not only localized mitochondrion but also localized chloroplast. The cis-elements of the SSADH gene family are related to the potential regulation of the banana SSADH gene family; their involvement in diverse stress responses. Transcriptomic data was utilized to examine the effect of MaSSADH genes under cold stress in bananas. The results of RT-qPCR were consistent with transcriptome data. These results showed that most MaSSADHs are passively responsive to low-temperature treatment. In addition, transient overexpression of MaSSADH1-14 in Nicotiana benthamiana leaves resulted in the content of GABA increasing, indicating that MaSSADH1-14 may be involved in the accumulation of GABA of banana. Collectively, these results improve knowledge of the SSADH gene family in banana and establish a basis for comprehending its biological roles in response to low temperatures.