S-adenosylmethionine synthase (SAMS) is a key enzyme catalyzing the synthesis of S-adenosylmethionine (SAM, S-adenosylmethionine), widely involved in various biological processes in plants, such as epigenetic regulation, oxidative stress, and growth and development. In this study, the full-length cDNA sequence of CaSAMS3 was successfully cloned from coffee, and the physicochemical properties, protein structure, conserved domains, and evolutionary characteristics of the encoded CaSAMS3 protein were analyzed. Through cis-acting element analysis and protein interaction network prediction, and the metabolic processes involving CaSAMS3 were explored, and its expression pattern was analyzed in combination with qPCR and subcellular localization studies. The results showed that the open reading frame length of CaSAMS3 was 1173 bp, encoding a hydrophilic protein (molecular weight 42.57 kDa, theoretical isoelectric point 6.07), with a secondary structure mainly composed of α- helices and irregular curls, and located on cell membrane and nucleus. The protein contained a typical SAMS conserved domain and had the highest homology with SAMS in kiwifruit. Its promoter contained response elements related to light, hormones, stress, and growth and development, including MYB and MYC binding sites. CaSAMS3 exhibited tissue-specific expression, and its expression trend during developmental stages was consistent with accumulation pattern of caffeine. This study would provide an important theoretical basis for elucidating the biological function of CaSAMS3 in the regulation of caffeine synthesis, and provides a potential target for improving coffee quality and resistance.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |