Inducing osmotic stress leads to better genetic transformation efficiency in cotton (Gossypium hirsutum L.)

Authors: SURENDRA BARPETE, ALLAH BAKHSH, EMİNE ANAYOL, SANCAR FATİH ÖZCAN, Muhammet Cağri OĞUZ, ÖMER CEM KARAKOÇ, SEBAHATTİN ÖZCAN

Abstract: The present study investigated the effect of different salts on cotton shoot regeneration and transformation efficiency. Two-day-old germinating embryos of a local cotton cultivar (SG-125) were pretreated with 50 mM each of NaCl, CaCl₂, and KCl for 60 min. The embryo explants were transformed by cocultivation with Agrobacterium tumefaciens strain LBA 4404 harboring a binary plasmid pTF101.1 that carried the insecticidal gene (cry1Ac) under control of wound-inducible promoter (AoPR1) and bilanafos acetyl reductase (bar) gene for plant selection. The salt-pretreated embryos showed maximum response on regeneration MS medium containing 0.50 mg/L 6-benzylaminopurine (BAP) and 0.10 mg/L indole-3-butyric acid (IBA), also supplemented with 5 mg/L bialaphos for in vitro screening of the transformed plantlets. The primary transformants were further screened by molecular techniques for integration and expression of the introduced gene. Maximum transformation efficiency (1.10%) was noted on KCl-treated explants compared to nontreated (control) explants. In conclusion, pretreatment of explants with 50 mM KCl for 60 min induced positive effects and triggered shoot regeneration in primary cotton transformants.

Keywords: Cotton, in vitro, osmotic treatment, regeneration, transformation

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