Efficient plant regeneration from multiple shoots formed in the leaf-derived callus of Lavandula vera, using the "open culture system".
Abstract To develop an efficient procedure for plant regeneration from leaf-derived callus of Lavandula vera DC, the production of multiple shoots and the formation of roots from these shoots were studied. When calli were cultured in a medium with 4.0×10−7 M N-(2-chloro-4-pyridyl)-N′-phenylurea (CPPU), urea-type cytokinin, multiple shoots were obtained from the greenish surface of the callus efficiently at a rate of 52.2%. For multiple shoot development, the shoots were divided into 7–20 shoot clusters with 2–3 shoots and subcultured every 2 weeks. Two modified culture-systems were employed for subculture; a “closed culture system” and an “open culture system”. In the open-system, shoot clusters grew and elongated vigorously. In the closed-system, most of the clusters showed vitrification and did not elongate. In root induction culture, shoot clusters in the open-system were well rooted and grew vigorously, the highest rate of root formation being 74.0%, in the 1 2 MS medium supplemented with 1.0×10−6 M indoleacetic acid (IAA). On the other hand, shoot clusters in the closed-system showed vitrification and did not root well. About seven times more regenerants were obtained from the multiple shoots than from normal shoots treated with 4.4×10−6 M 6-benzylamino purine (BA), a purine-type cytokinin. These results indicate that efficient plant regeneration in L. vera from callus using multiple shoots is possible by means of an open-system.
Trichomes, essential oils and in vitro propagation of Lavandula pedunculata (Lamiaceae)
Lavanders (Lavandula spp.) are aromatic plants with high industrial and commercial value, used in food industry, perfumery and pharmaceutical preparations. Micropropagation can be used for large-scale multiplication of essential oil producing plants thus avoiding an overexploitation of natural resources. This work aims to develop a reliable protocol for the in vitro propagation of Lavandula pedunculata and to evaluate the potential of these plants for essential oil production with industrial application. In vitro cultures were established on media with different concentrations of benzyladenine. Trichome morphology was examined by SEM and their secretion analyzed by histochemical tests. Essential oils were isolated by hydrodistillation and analyzed by GC and GC-MS. The essential oils and trichomes of in vitro plants were compared with those of field-growing plants. Best propagation rates were achieved with 0.25 mg/l BA. Rooting occurred without treatment with auxins thus preventing callus growth. Trichomes and essential oils of the in vitro propagated plants were similar to those of the parent plants. Two chemotypes were characterized: 1,8-cineole/camphor type and fenchone type. Since trichomes and essential oils of L. pedunculata micropropagated plantlets are identical to those produced by field-growing plants, in vitro cultures can be used for essential oil production without affecting natural resources. Moreover, the quality of the essential oils is assured and this protocol can be further applied to the propagation of selected chemotypes for industrial purposes.
Genetics of the phenotypic evolution in sheep: a molecular look at diversity-driving genes
Background After domestication, the evolution of phenotypically-varied sheep breeds has generated rich biodiversity. This wide phenotypic variation arises as a result of hidden genomic changes that range from a single nucleotide to several thousands of nucleotides. Thus, it is of interest and significance to reveal and understand the genomic changes underlying the phenotypic variation of sheep breeds in order to drive selection towards economically important traits. Review Various traits contribute to the emergence of variation in sheep phenotypic characteristics, including coat color, horns, tail, wool, ears, udder, vertebrae, among others. The genes that determine most of these phenotypic traits have been investigated, which has generated knowledge regarding the genetic determinism of several agriculturally-relevant traits in sheep. In this review, we discuss the genomic knowledge that has emerged in the past few decades regarding the phenotypic traits in sheep, and our ultimate aim is to encourage its practical application in sheep breeding. In addition, in order to expand the current understanding of the sheep genome, we shed light on research gaps that require further investigation. Conclusions Although significant research efforts have been conducted in the past few decades, several aspects of the sheep genome remain unexplored. For the full utilization of the current knowledge of the sheep genome, a wide practical application is still required in order to boost sheep productive performance and contribute to the generation of improved sheep breeds. The accumulated knowledge on the sheep genome will help advance and strengthen sheep breeding programs to face future challenges in the sector, such as climate change, global human population growth, and the increasing demand for products of animal origin.