Effects of mammalian sex hormones on in vitro organogenesis of common bean (Phaseolus vulgaris L.)

Abstract

Beans are an important plant species and are one of the most consumed legumes in human nutrition, especially as a protein, vitamin, mineral, and fiber source. Common bean (Phaseolus vulgaris L.) is a plant that also has an important role in natural nitrogen fixation. Currently, in vitro regeneration and micropropagation applications are limited in relation to genetic factors in bean Accordingly, there is great need to optimize micropropagation and tissue culture methods of the bean plant. To date, the effect of mammalian sex hormones (MSH) on in vitro conditions in P. vulgaris L. is poorly understood. This study examined the effects of different types of explants (embryo, hypocotyl, plumule, and radicle), MSH type (progesterone, 17 β-estradiol, estrone, and testosterone), and MSH concentration (10^-4, 10^-6, 10^-8 and 10^-10 mmol L^-1) on the responding explants induction rate (REI), viability of plantlets rate (VPR), shoot proliferation rate (SPR), root proliferation rate (RPR), and callus induction rate (CIR). The effects of mammalian sex hormones, concentrations, explant type, and their interactions were statistically significant (p ≤ 0.01) in all examined parameters. The best explants were embryo and plumule. Our results showed that the highest REI rate (100%) was recorded when 10^-10 mmol L^-1 of all MSH was applied to MS medium using the plumule explant. The highest VPR (100%) was obtained when 10^-10 mmol L^-1 of all MSH was applied to MS medium using the plumule explant. The highest root proliferation rates (77.5%) were recorded in MS medium supplemented with 10^-8 mmol L^-1 17β-estradiol using embryo explant. The highest percentage of shoot-forming explants (100%) generally was obtained from embryo and plumule cultured in the MS culture medium with low MSH concentration. In addition, the highest CIR (100%) was obtained from embryo and plumule explant cultured in MS medium containing 10^-10 mmol L^-1 of all MSH types. In conclusion, we observed that mammalian sex hormones may be used in bean in vitro culture.