High plant regeneration and ectopic expression of OsMADS1 gene in root chicory (Cichorium intybus L. var. sativus)

Optimal shoot regeneration and transformation conditions of root type chicory (Cichorium intybus L. var. sativus cv Cesare) were studied. Leaf explants were co-cultured with Agrobacterium tumefaciens, which contained NPTII as a selectable marker and a rice homeotic gene, OsMADS1, that encodes a MADS-domain-containing transcription factor. After one day of co-cultivation, explants were transferred to selection media consisting of MS basal medium supplemented with 0.5 mg/L BAP, 0.1 mg/L IAA, 70 mg/L kanamycin, and 250 mg/L cefotaxime. PCR and Southern blot analyses revealed stable integration of the OsMADS1 gene in the chicory genome. Four-teen original transgenic plants ($T_o$ plants) were acclimatized in the greenhouse and examined for their morphological characters. Most of the transgenic plants showed altered morphologies, such as short, bushy, and early-flowering phenotypes with reduced apical dominance. Additionally, half of the transgenic plants exhibited altered leaf shapes, and 4 out of 14 plants were sterile. These phenotypes were inherited by the next generation. Northern blot analysis confirmed expression of the OsMADS1 gene in both floral and vegetative organs.