Production of Virus-Free Garlic Plants through Somatic Embryogenesis

Abstract

The present study was conducted to establish a protocol for the regeneration of virus-free garlic plants through somatic embryogenesis of two Croatian garlic ecotypes. Basal parts of cloves from mother plants were cultured on a full Murashige and Skoog (MS) or modified MS medium (¼ of KNO3 and NH4NO3 and 2xMgSO4) containing 0.1 mg L−1 2,4-dichlorophenoxyacetic acid (2,4-D) or 1 mg L−1 2,4-D + 0.5 mg L−1 kinetin (Kin) and representing four different treatments. Plants were regenerated in MS medium containing 0.1 mg L−1 2,4-D and rooted in a medium containing 0.05 mg L−1 1-naphthaleneacetic acid (NAA) + 0.005 mg L−1 6-(γ,γ-dimethylallylamino)purine (2iP). The presence of viruses (i.e., sanitary status) of the mother plants and regenerants was checked by enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR). The mother plants were infected with onion yellow dwarf virus (OYDV) and leek yellow stripe virus (LYSV). In addition, the presence of garlic common latent virus (GCLV) was confirmed in four mother plants. Embryogenic callus developed in all four treatments with success ranging from 55% to 81% depending on treatment and ecotype. Plant conversion was significantly higher in somatic embryos developed in media containing 0.1 mg L−1 2,4-D than those developed in media containing 1 mg L−1 2,4-D + 0.5 mg L−1 Kin. Virus elimination success ranged from 13.3% up to 62.5% depending on garlic ecotype and treatment. The overall rate of virus elimination by somatic embryogenesis for both treatments and ecotypes were 20.7%, 22.9%, and 30.5% for OYDV, GCLV, and LYSV, respectively. Based on these results, somatic embryogenesis has been shown to be equally or more successful in eliminating garlic viruses compared to other in vitro methods.

Efficient Elimination of Viruses from Garlic Using a Combination of Shoot Meristem Culture, Thermotherapy, and Chemical Treatment

“…The efficiency of the technique depends on the type and the accumulation level of a virus in the plant, its physiology, and plants’ resistance level [ 47 ]. Techniques such as tissue culture (meristem culture, somatic embryogenesis); cold, chemical, and heat treatments; or tissue culture combined with cold, chemical, and heat treatments have been applied to eliminate viruses [ 14 , 28 , 37 , 39 , 48 , 49 , 50 ]. The success of any approach does not depend only on virus elimination but also on the successful recovery of virus-free garlic plants.…”

Recovery of virus-free Almond (Prunus dulcis) cultivars by somatic embryogenesis from meristem undergone thermotherapy

“…Also, virus-free garlic plants were regenerated through somatic embryogenesis from basal parts of cloves of two Croatian garlic ecotypes on MS medium containing 0.1 mg/L 2,4-D. The results showed that the elimination of onion yellow dwarf virus (OYDV), leek yellow stripe virus (LYSV) and garlic common latent virus (GCLV) was as successful as other methods 45 . Somatic embryogenesis of tepal flower tissue in Hippeastrum hybridum was performed on MS medium containing 0.5 mg/L 2,4-D and 1 mg/L TDZ.…”

Somatic Embryogenesis: A Tool for Fast and Reliable Virus and Viroid Elimination for Grapevine and other Plant Species

“…In the case of the different garlic ecotypes the elimination efficiencies were between 13 and 63%, which shows a strong genotype effect in SE-based elimination [46]. In cassava, the age of the callus tissues and long regeneration period probably reduced the efficiency for the 'Ankrah' cultivar [31].…”