Search

The genus Jasminum L., of the family Oleaceae, includes many species occurring in the wild, or cultivated worldwide. A preliminary investigation based on inter-simple sequence repeats (ISSR) was performed to assess the genetic diversity among 28 accessions, representing nine species of Jasminum from various regions, representing a range of altitudes in Pakistan. A total of 21 ISSR primers were used, which produced 570 amplified bands of different sizes, with a mean polymorphic band percentage of 98.26%. The maximum resolving power, polymorphism information content, and index values of the ISSR markers recorded for primers 6, 16, and 19 were 0.40, 12.32, and 24.21, respectively. Based on the data of the ISSR markers, the resulting UPGMA dendrogram with the Jaccard coefficient divided the 28 accessions into two main clades. At the species level, the highest values for Shannon’s information index, polymorphism percentage, effective allele number, Nei’s genetic variations, and genetic unbiased diversity were found in Jasminum sambac L. and J. humile L., while the lowest were observed in J. mesnyi Hance and J. nitidum Skan. Based on Nei’s unbiased genetic identity pairwise population matrix, the maximum identity (0.804) was observed between J. elongatum Willd and J. multiflorum (Burm. f.) Andrews, and the lowest (0.566) between J. nitidum Skan. and J. azoricum L. Molecular variance analysis displayed a genetic variation of 79% among the nine populations. The study was aimed to established genetic diversity in Jasminum species using ISSR markers. With the help of this technique, we were able to establish immense intra- and interspecific diversity across the Jasminum species.

Global warming has two dangerous global consequences for agriculture: drought, due to water scarcity, and salinization, due to the prolonged use of water containing high concentrations of salts. Since the global climate is projected to continue to change over this century and beyond, choosing salt-tolerant plants could represent a potential paramount last resort for exploiting the secondary saline soils. Olive is considered moderately resistant to soil salinity as compared to other fruit trees, and in the present study, we investigated the influence of NaCl solutions (ranging from 0 to 200 mM) in a salt-tolerant (cv Canino) and two of its transgenic lines (Canino AT17-1 and Canino AT17-2), overexpressing tobacco osmotin gene, and in a salt-sensitive (Sirole) olive cultivar. After four weeks, most of the shoots of both Canino and Sirole plants showed stunted growth and ultimate leaf drop by exposure to salt-enriched media, contrary to transgenic lines, that did not show injuries and exhibited a normal growth rate. Malondialdehyde (MDA) content was also measured as an indicator of the lipid peroxidation level. To evaluate the role of the S assimilatory pathway in alleviating the adverse effects of salt stress, thiols levels as well as extractable activities of ATP sulfurylase (ATPS) and O-acetyl serine(thiol)lyase (OASTL), the first and the last enzyme of the S assimilation pathway, respectively, have been estimated. The results have clearly depicted that both transgenic lines overexpressing osmotin gene coped with increasing levels of NaCl by the induction of S metabolism, and particularly increase in OASTL activity closely paralleled changes of NaCl concentration. Linear correlation between salt stress and OASTL activity provides evidence that the S assimilation pathway plays a key role in adaptive response of olive plants under salt stress conditions.

Research on biologically active compounds has been increased in order to improve plant protection against various environmental stresses. Among natural sources, plants are the fundamental material for studying these bioactive compounds as their immune system consists of many peptides, proteins, and hormones. Osmotin is a multifunctional stress-responsive protein belonging to pathogenesis-related 5 (PR-5) defense-related protein family, which is involved in inducing osmo-tolerance in plants. In this scenario, the accumulation of osmotin initiates abiotic and biotic signal transductions. These proteins work as antifungal agents against a broad range of fungal species by increasing plasma membrane permeability and dissipating the membrane potential of infecting fungi. Therefore, overexpression of tobacco osmotin protein in transgenic plants protects them from different stresses by reducing reactive oxygen species (ROS) production, limiting lipid peroxidation, initiating programmed cell death (PCD), and increasing proline content and scavenging enzyme activity. Other than osmotin, its homologous proteins, osmotin-like proteins (OLPs), also have dual function in plant defense against osmotic stress and have strong antifungal activity.

Gladiolus is one of the most important lucrative cut flower crops that is commercially cultivated worldwide due to its various spike forms, size, and shape and color combinations. In order to further increase the commercial and horticultural value by improving the ornamental traits of gladiolus ‘White Prosperity’, polyploidy was induced by soaking gladiolus corms in different colchicine concentrations (0.1%, 0.2% and 0.3%) for 24 h. Different colchicine concentrations had a little effect on sprouting and survival percentage but it significantly delayed the emergence of sprouts. About one third decreases in plant height along with reduction in number of leaves per plant, leaf area, length and width, chlorophyll content, diameter and number of cormlets per corm was observed in treated plants. Colchicine at 0.1% concentration improved the ornamental value of gladiolus by increasing vase life whereas colchicine at 0.3% was effective in increasing floret diameter. However, the colchicine treated plants exhibited delayed and reduced percentage of flowering corms. Pollen and stomatal study was done for the identification of polyploidy and it showed that both pollen and stomata size were increased while stomatal density and pollen fertility was significantly reduced in polyploid plants. Induction of polyploidy (mixoploids + octoploids) was achieved in all concentrations, however 0.2% and 0.3% concentrations of colchicine were effective for producing large number of polyploid plants. But at 0.1% concentration of colchicine, majority of plants did not show any change in their original ploidy level (tetraploid). These putative polyploids may be helpful for further improvement in ornamental and horticultural value of gladiolus.

Polyploidy has the utmost importance in horticulture for the development of new ornamental varieties with desirable morphological traits referring to plant size and vigor, leaf thickness, larger flowers with thicker petals, intense color of leaves and flowers, long lasting flowers, compactness, dwarfness and restored fertility. Polyploidy may occur naturally due to the formation of unreduced gametes or can be artificially induced by doubling the number of chromosomes in somatic cells. Usually, natural polyploid plants are unavailable, so polyploidy is induced synthetically with the help of mitotic inhibitors. Colchicine is a widely used mitotic inhibitor for the induction of polyploidy in plants during their cell division by inhibiting the chromosome segregation. Different plant organs like seeds, apical meristems, flower buds, and roots can be used to induce polyploidy through many application methods such as dipping/soaking, dropping or cotton wool. Flow cytometry and chromosome counting, with an observation of morphological and physiological traits are routine procedures for the determination of ploidy level in plants.