Polyamines and WOX genes in the recalcitrance to plant conversion of somatic embryos of Habanero pepper (Capsicum chinense Jacq.)

Abstract

In order to determine the role of polyamines in the formation and development of the somatic embryos of Capsicum chinense, the effect of different concentrations (0, 0.01, 0.1, and 1.0 mM) of Putrescine, Spermidine and Spermine on the efficiency and morphology of the embryos was evaluated. The results show that none of the three polyamines evaluated had a significant effect on the number of embryos formed, except Spermidine (1 mM), which caused a significant reduction in their numbers, in comparison with the control treatment. However, the most noteworthy result was observed in the treatment containing 0.1 mM of Spermine. The embryos developed in this treatment showed harmonic apex-radicle development, pale-green coloration and the formation of two tiny cotyledonary leaves. Real-time PCR was used to analyze the differential expression of the WUS, WOX1 and WOX3 genes in somatic embryos treated with Spermine and untreated, including the zygotic embryo. The transcript levels of the genes analyzed were found to differ significantly between both types of embryos (somatic and zygotic), with the zygotic embryos presenting a higher level of transcripts; however, compared to the untreated somatic embryos, the somatic embryos treated with Spermine showed an increase in the transcript levels of the three genes analyzed (WUS, WOX1 and WOX3); the WOX1 gene in particular presented an accumulation pattern similar to that of the zygotic embryo of the species.

Somatic Embryogenesis: Fundamental Aspects and Applications

“…This cell suspension was further pretreated with potassium citrate (6 g/L) and then cultured in the initiation medium consisting of MS with 6 g/L proline and a reduction in ammonium concentration from 20 to 10 mM. Very recently, Valle-Gough et al (2015) analyzed the influence of the polyamines putrescine, spermidine, and spermine at 0, 0.01, 0.1, and 1.0 mM on the efficiency of somatic embryogenesis and the morphology of the regenerated somatic embryos in C. chinense var. Somatic embryogenesis in chili pepper was also reported using young leaves of C. annuum cv.…”

Somatic Embryogenesis in Capsicum spp.

“…Solís-Ramos et al (2010) established a protocol for the induction of indirect somatic embryogenesis in C. chinense starting with mature zygotic embryos segments as explants, which were cultured on MS medium supplemented with 8.9 μM NAA, 11.4 μM IAA, and 8.6 μM BA to produce embryogenic callus; only 8 % of calli produced somatic embryos and when torpedo-stage somatic embryos were detached from callus and cultured on MS medium without growth regulators a 75 % conversion into plantlets was attained; these plants were finally transplanted to soil and adapted to greenhouse conditions. Very recently, Valle-Gough et al (2015) analyzed the influence of the polyamines putrescine, spermidine, and spermine at 0, 0.01, 0.1, and 1.0 mM on the efficiency of somatic embryogenesis and the morphology of the regenerated somatic embryos in C. chinense var. Mayan Ba'alche applying the protocol described by Avilés-Viñas et al (2013).…”