An antimicrobial peptide (SAMP) derived from Microcitrus australasica can not only reduce the concentration of Candidatus Liberibacter asiaticus (CLas) in the infected trees and reduce the symptoms of the diseased trees, but also induce innate immunity and prevent the infection of Huanglongbing in healthy trees that are not infected with Huanglongbing. MaSAMP was analyzed by functional structure, subcellular localization and phylogeny. The results showed that the open reading frame (ORF) of MaSAMP was 201 bp in length, encoding 67 amino acids. The molecular weight of the corresponding protein was 7.59959 kDa, the theoretical isoelectric point was 5.38, and the instability index (Instability index (II)) was 33.22. The aliphatic index was 87.16%, and the grand average of hydropathicity was -0.09, indicating that the protein was a hydrophilic one. The protein contained one Dabb domain and was predominantly structured by α-helices and random coils. In terms of evolution, MaSAMP was phylogenetically close to the stress-response A/B barrel domain-containing protein CISIN_1g033887mg from Citrus sinensis and the A/B barrel domain protein HS1 from Citrus×clementina, with protein similarity of 97.01% and 91.04%, respectively. Subcellular localization results indicated that MaSAMP was localized in chloroplasts. Furthermore, through homologous recombination, a pCAMBIA1300-35S::MaSAMP-EGFP overexpression vector fused with an EGFP fluorescent tag was successfully constructed, and transgenic citrus plants were obtained using agrobacterium-mediated in planta transformation technology. This study would provide a material basis for subsequent research on the biological functions of MaSAMP.
| 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 |