Isolation and expression of antimicrobial Camel lactoferrin (cLf) gene in tobacco

In this study, cDNA encoding the Camelus dromedarius lactoferrin (cLf) was isolated from mammary gland by reverse transcription polymerase chain reaction and cloned to the pART27 expression vector. Its predicted amino acid sequence was analyzed and compared with lactoferrin of other mammalian species. Secondary and tertiary structures were predicted and modeled by online tools. Then cLf cDNA was expressed in Nicotiana tobaccum cv. Xanthi using Agrobacterium mediate transformation. Analysis of transgenic plants by PCR, RT-PCR and Real-time PCR showed the recombinant camel lactoferrin gene was expressed in transgenic plants. Tests on protein extract from transgenic tobacco leaves demonstrated antimicrobial activity against microbial strains. Evaluations for inhibition efficiency against Staphylococcus aureus PTCC1112 (ATCC 6538), Escherichia coli PTCC 1330 (ATCC 8739), Bacillus subtilis PTCC1023 (ATCC 6633) and Candida albicans PTCC5027 (ATCC 10231) were 48.8%, 52.7%, 34.6% and 41.6%, respectively. However, tests on protein extract from non-transformed plants did not display any sign of antimicrobial activity. Lactoferrin is a valuable protein that takes part in a large number of important physiological processes. Lf expression in plants provides a suitable system for large-scale production of this protein. Furthermore, it has been demonstrated that Lf expression in plants confers resistance to plant diseases, so this antimicrobial protein could also be used to improve crop quality.