V. A. Bapat

Ripening of fleshy fruit: molecular insight and the role of ethylene.

Development and ripening in fruit is a unique phase in the life cycle of higher plants which encompasses several stages progressively such as fruit development, its maturation, ripening and finally senescence. During ripening phase, several physiological and biochemical changes take place through differential expression of various genes that are developmentally regulated. Expression and/or suppression of these genes contribute to various changes in the fruit that make it visually attractive and edible. However, in fleshy fruit massive losses accrue during post harvest handling of the fruit which may run into billions of dollars worldwide. This encouraged scientists to look for various ways to save these losses. Genetic engineering appears to be the most promising and cost effective means to prevent these losses. Most fleshy fruit ripen in the presence of ethylene and once ripening has been initiated proceeds uncontrollably. Ethylene evokes several responses during ripening through a signaling cascade and thousands of genes participate which not only sets in ripening but also responsible for its spoilage. Slowing down post ripening process in fleshy fruit has been the major focus of ripening-related research. In this review article, various developments that have taken place in the last decade with respect to identifying and altering the function of ripening-related genes have been described. Role of ethylene and ethylene-responsive genes in ripening of fleshy fruit is also included. Taking clues from the studies in tomato as a model fruit, few case studies are reviewed.

Artocarpus: a review of its traditional uses, phytochemistry and pharmacology.

The genus Artocarpus (Moraceae) comprises about 50 species of evergreen and deciduous trees. Economically, the genus is of appreciable importance as a source of edible fruit, yield fairly good timber and is widely used in folk medicines. The aim of the present review is to present comprehensive information of the chemical constituents, biological and pharmacological research on Artocarpus which will be presented and critically evaluated. The close connection between traditional and modern sources for ethnopharmacological uses of Artocarpus species, especially for treatment against inflammation, malarial fever, diarrhoea, diabetes and tapeworm infection. Artocarpus species are rich in phenolic compounds including flavonoids, stilbenoids, arylbenzofurons and Jacalin, a lectin. The extracts and metabolites of Artocarpus particularly those from leaves, bark, stem and fruit possess several useful bioactive compounds and recently additional data are available on exploitation of these compounds in the various biological activities including antibacterial, antitubercular, antiviral, antifungal, antiplatelet, antiarthritic, tyrosinase inhibitory and cytotoxicity. Several pharmacological studies of the natural products from Artocarpus have conclusively established their mode of action in treatment of various diseases and other health benefits. Jacalin, a lectin present in seeds of this plant has a wide range of activities. Strong interdisciplinary programmes that incorporate conventional and new technologies will be critical for the future development of Artocarpus as a promising source of medicinal products. In the present review, attempts on the important findings have been made on identification; synthesis and bioactivity of metabolites present in Artocarpus which have been highlighted along with the current trends in research on Artocarpus.

Sandalwood plantlets from ‘Synthetic seeds’

Somatic embryos of sandalwood (Santalum album) were encapsulated in an alginate matrix to prepare ‘Synthetic seeds’. Encapsulated single embryos germinated to form plants with roots and shoots. Embryogenic cell suspensions encapsulated and stored at 4°C for 45 days produced embryos when recultured as suspensions.

Propagation of banana through encapsulated shoot tips.

Plants were regenerated from encapsulated shoot tips of banana. Shoot tips (ca 4 mm) isolated from multiple shoot cultures of banana cv. Basrai were encapsulated in 3% sodium alginate containing different gel matrices. The encapsulated shoot tips regenerated in vitro on different substrates. Use of Whites medium resulted in 100% conversion of encapsulated shoot tips into plantlets. The plantlets were successfully established in soil.

Biotechnological strategies for phytoremediation of the sulfonated azo dye Direct Red 5B using Blumea malcolmii Hook

Tissue cultured shrub plants of Blumea malcolmii were found to decolorize Malachite green, Red HE8B, Methyl orange, Reactive Red 2 and Direct Red 5B at 20 mg L(-1) concentration to varying extent within three days. A significant induction in the activities of lignin peroxidase, tyrosinase, DCIP (2,6-dichlorophenol-indophenol) reductase, azoreductase and riboflavin reductase in the roots was observed during the decolorization of Direct Red 5B, which indicated their crucial role in the metabolism of the dye. HPLC (High Performance Liquid Chromatography) and FTIR (Fourier Transform Infrared Spectroscopy) analysis of the samples before and after decolorization of the dye confirmed the phytotransformation of Direct Red 5B. The GC-MS (Gas Chromatography Mass Spectroscopy) analysis of the products led us to the identification of three metabolites formed after phytotransformation of the dye as 4-(4-amino-phenylazo)-benzene sulfonic acid, 3-amino-7-carboxyamino-4-hydroxy-naphthalene-2-sulfonic acid and 7-carboxyamino-naphthalene-2-sulfonic acid.

Evaluation of Antioxidant Capacity and Phenol Content in Jackfruit (Artocarpus heterophyllus Lam.) Fruit Pulp

The antioxidant capacity of jackfruit (Artocarpus heterophyllus Lam. Fam. Moracae) fruit pulp (JFP) obtained from Western Ghats India was determined by evaluating the scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing power assays and N, N-dimethyl-p-phenylendiamine (DMPD) radical cation decolorization assay. JFP was analyzed for total phenolic content (TPC) and total flavonoids content (TFC). The ethanol and water are the best solvents for the extracting phenols and flavonoids from the JFP. The antioxidant activities of JFP extracts were correlated with the total phenolic and flavonoids content. The results indicated that the jackfruit pulp is one natural source of antioxidant compounds.

Regeneration of plants from the culture of leaves and axillary buds in mulberry (Morus indica L.)

Stem segments, axillary buds and leaves excised from established shoot cultures of Morus indica were soaked in MS liquid medium containing benzyladenine (0.5, 1, 2 mg/1) and were cultured subsequently on semi solid medium of the same composition. Numerous shoot buds differentiated from leaf and axillary buds but stem segments were unresponsive. The shoot buds on isolation and culture developed into plantlets. Callus tissues which developed at the base of the leaf explant upon subculture also differentiated numerous shoot buds.

Regeneration of plants from alginate-encapsulated somatic embryos of banana cv. Rasthali (Musa SPP. AAB Group)

SummarySomatic embryos of banana cv. Rasthali (AAB genomic group) were encapsulated in 5% sodium alginate to produce synthetic seeds. The frequency of germination of ecapsulated embryos varied considerably on different gel matrices and substrates used for plant development. Maximum conversion frequency of 66% was noted from encapsulated embryos cultured on MS medium. Plantlets developed from synthetic seeds were successfully trnasferred to soil.

In vivo growth of encapsulated axillary buds of mulberry (Morus indica L.).

Axillary buds excised from aseptic shoot cultures of mulberry were encapsulated in an alginate matrix under non-aseptic conditions. Addition of a fungicide to the alginate beads prevents contamination of the bud and increased survival of the buds when sown in soil.

In vitro plant regeneration in Melia azedarach L.

Abstract Nodal explants of 3- 6-week-old seedlings cultured on Murashige and Skoog (MS) medium supplemented with 6-benzyladenine (BA) (17.75 μm) produced multiple shoots. Shoots were isolated and induced to root on 1/2-strength MS medium supplemented with indole-3-butyric acid (4.92 μm). In-vitro-rooted shoots resumed growth after a short period of acclimatization and resulted in plantlets which were successfully established in soil. In vitro flowering was observed in some of the nodal explants in the above medium, and also in cotyledonary leaves and internodal explants on MS medium supplemented with a combination of indole-3-acetic acid (IAA) (0.06 μm)+BA (4.44 μm) and IAA (0.06 μm)+kinetin (4.65 μm).