انتقال جينات T-DNA المحمولة على بلازميدات Ri من بكتريا Agrobacterium rhizogenes R1601 بوساطة الحقن المباشر و الزراعة المرافقة إلى أنسجة الجزر Daucus carota L. و تكوين مزارع الجذور الشعرية المحورة وراثيا

Abstract EN

The present study detected the optimal requirements to produce hairy roots on stem segments and root discs of carrot, Daucus carota L., by the natural vector for genetic transformation A.rhizogenes R1601.

Direct inoculation of stems segment by bacterial inoculum of density 96x108cell/ml was efficient and sustained the initiation of hairy roots after 10-15 days.

They developed on inoculated and noninoculated sites at percent reached up to 49.9% with a mean of 5.6 hairy roots /segment.

Hairy roots excised were as single or clusters of roots and placed on agar-solidified MS medium.

They were transferred to MS medium supplemented with gradual concentrations 100, 200, 300 mg/L of antibiotic Cefotaxime through several subsequent transfer to eliminate bacteria.

Finally, cultures of hairy roots free from bacteria was developed on MS medium which considered as selection medium.

This phenotype of hairy roots was fast growing, brown in color, lacking of root hairs and negatively geotropism.

Also, hairy roots were formed on carrot discs, via Co_cultivation with A.

rhizogenes R1601 for 8 hours which appeared the best time, after 25 days at a percent of 17.8% and a ratio of 3 hairy root/disc.

This phenotype of hairy root was slow in growth, white in colour and express less branching.

Paper electrophoresis results demonstrated the present of agropine in both phenotype of hairy roots which proved the incidence of genetic transformation of these roots compared with the normal root (control).