Early studies on the effect of peptide growth factor phytosulfokine-α on Brassica oleracea var. capitata L. protoplasts

Abstract

<span>Phytosulfokines (PSK) are peptidyl growth factors with the potential of inducing cell proliferation. We examined the effect of supplementation of liquid culture medium with 0.1 µM phytosulfokine-α (PSK-α) on protoplast viability and division frequencies in seven accessions of <em>Brassica oleracea</em> var. <em>capitata</em> L., including cultivars and breeding lines. Protoplasts were isolated from leaves and hypocotyls of in vitro grown plants and immobilized in calcium-alginate layers. Cabbage protoplast-derived cells cultured in medium supplemented with 0.1 µM of PSK-α had higher viability and division frequencies compared to cells cultured in PSK-α-free control medium. The effect of PSK-α was more pronounced in low-responding accessions (‘Sława z Gołębiewa’, ‘Ramkila F1’, LM, and LM98); however, in two cultivars with very low response (‘Badger Shipper’ and ‘Oregon 123’), although the division frequencies in the media supplemented with PSK-α were increased over the control, the differences were not significant. Obtained callus colonies were subjected to regeneration. PSK-α supplemented into the liquid culture medium had an indirect effect on shoot regeneration by inducing sustained cell divisions leading to an increase in shoot regeneration in Sława z Gołębiewa and both breeding lines.</span>