Development of an in vitro regeneration system for genetic transformation in peanut variety L27 (Arachis hypogaea L.)

Abstract

Arachis hypogaea L. has high nutritional value for human health; however, its proteins are highly allergenic, and the levels of essential sulfur-containing amino acids are relatively low. Moreover, peanut yield and nutritional value are adversely affected by abiotic stresses, including drought, extreme temperatures, salinity, flooding, and elevated CO₂ concentrations. This study aimed to develop an efficient regeneration system for Agrobacterium-mediated genetic transformation to enhance stress tolerance and improve seed quality in peanuts. The results indicated that the most effective seed sterilisation was achieved using 0.1% mercury(II) chloride (HgCl₂) for a total of 9 minutes (5 minutes for the first treatment and 4 minutes for the second treatment). The optimal shoot tip regeneration was observed at 1.5 mg/l benzylaminopurine (BAP), while cotyledon axil explants showed the best response at 2.0 mg/l BAP. Multiple shoot induction from cotyledon axil explants was most successful with a combination of 2.0 mg/l BAP and 0.7 mg/l α-naphthaleneacetic acid (α-NAA), producing an average of 4.43 shoots per explant. In contrast, apical shoot tips did not induce multiple shoot formation. The highest rooting efficiency was achieved with 0.7 mg/l α-NAA, resulting in an average of 8.32 roots per shoot. Kanamycin selection was effective at 75 mg/l during shoot regeneration and 50 mg/l during rooting.