Stem thin disc (STD) based somatic embryogenesis and genetic homogeneity assessment in Alhagi maurorum Medik

Alhagi maurorum (camelthorn) is a woody shrub of arid and semi-arid ecosystems. It contributes to soil stability, land restoration, phytoremediation of heavy metals, carbon sequestration, climate regulation, traditional medicine, and the pharmaceutical industry. To assist such use, an efficient protocol for somatic embryogenesis from Stem Thin Disc (STD) culture technology has been established. Stem thin discs prepared from in vitro regenerated shoots responded to 1 mg l^-1 NAA (1-naphthalene acetic acid) and 1 mg l^-1 BAP (6-benzyl amino purine) fortified MS media with a maximum 72.22% regeneration frequency/inoculum within 18 days. The regenerated creamy white, granular, and fast-growing embryogenic callus was differentiated into a compact mass of yellowish green embryos on BAP (0.5 mg l^-1) + NAA (1.0 mg l^-1) + additives fortified MS medium. The mature embryos germinated into complete plantlets with a maximum 66.67 ± 1.73% germination rate in 25-28 days of transfer to germination medium. Among the total germinated embryos, 23.33% of complete plantlets were obtained. A total of six molecular markers, comprising three inter simple sequence repeat (ISSR) and three start codon targeted (SCoT) primers, were employed to assess the genetic homogeneity of the in vitro regenerated plantlets. The ISSR markers revealed 100% monomorphism, while SCoT markers exhibited 93.33% monomorphism, resulting in an overall genetic homogeneity of 96.66% between the regenerated plantlets and the mother plant. This efficient protocol reported here is the first report on Alhagi maurorum that may greatly facilitate the large-scale production of plantlets with genetic stability.