Genetic modifications of horticultural plants by induced mutations and transgenic approach

Climate change has pressed the need to develop improved horticultural crop cultivars capable of tolerating extreme environmental conditions besides sustaining yield and quality. Induced mutations provide a viable option for the generation of a novel genetic variation. In horticultural crops, more than 800 mutant cultivars have so far been developed, and a majority of them are ornamentals followed by vegetables, fruits, decorative trees, berries, nuts, ornamentals and other plants. Transgenic technology has also led to the improvement of horticultural crops for plant type, fruit-shelf life, floral and quality assets besides resistance to biotic and abiotic stresses. Mutagenesis techniques have been integrated with in vitro culture and other molecular biology technologies, such as molecular markers and high-throughput mutation screening, thereby becoming more powerful and effective in crop breeding.Peer reviewe

Transcriptomics profiling of Indian mustard (Brassica juncea) under arsenate stress identifies key candidate genes and regulatory pathways

© 2015 Srivastava, Srivastava, Sablok, Deshpande and Suprasanna. Arsenic (As) is a non-essential element, a groundwater pollutant, whose uptake by plants produces toxic effects. The use of As-contaminated groundwater for irrigation can affect the crop productivity. Realizing the importance of the Brassica juncea as a crop plant in terms of oil-yield, there is a need to unravel mechanistic details of response to As stress and identify key functional genes and pathways. In this research, we studied time-dependent (4–96 h) transcriptome changes in roots and shoots of B. juncea under arsenate [As(V)] stress using Agilent platform. Among the whole transcriptome profiled genes, a total of 1,285 genes showed significant change in expression pattern upon As(V) exposure. The differentially expressed genes were categorized to various signaling pathways including hormones (jasmonate, abscisic acid, auxin, and ethylene) and kinases. Significant effects were also noticed on genes related to sulfur, nitrogen, CHO, and lipid metabolisms along with photosynthesis. Biochemical assays were conducted using specific inhibitors of glutathione and jasmonate biosynthesis, and kinases. The inhibitor studies revealed interconnection among sulfur metabolism, jasmonate, and kinase signaling pathways. In addition, various transposons also constituted a part of the altered transcriptome. Lastly, we profiled a set of key functional up- and down-regulated genes using real-time RT-PCR, which could act as an early indicators of the As stress

Induced genetic diversity in banana

Induced genetic diversity in banana.Peer reviewe

Plant Cell Cultures : Biofactories for the Production of Bioactive Compounds

Plants have long been exploited as a sustainable source of food, flavors, agrochemicals, colors, therapeutic proteins, bioactive compounds, and stem cell production. However, plant habitats are being briskly lost due to scores of environmental factors and human disturbances. This necessitates finding a viable alternative technology for the continuous production of compounds that are utilized in food and healthcare. The high-value natural products and bioactive compounds are often challenging to synthesize chemically since they accumulate in meager quantities. The isolation and purification of bioactive compounds from plants is time-consuming, labor-intensive, and involves cumbersome extraction procedures. This demands alternative options, and the plant cell culture system offers easy downstream procedures. Retention of the metabolic cues of natural plants, scale-up facility, use as stem cells in the cosmetics industry, and metabolic engineering (especially the rebuilding of the pathways in microbes) are some of the advantages for the synthesis and accumulation of the targeted metabolites and creation of high yielding cell factories. In this article, we discuss plant cell suspension cultures for the in vitro manipulation and production of plant bioactive compounds. Further, we discuss the new advances in the application of plant cells in the cosmetics and food industry and bioprinting.Peer reviewe

Alterations in stem sugar content and metabolism in sorghum genoptypes subjected to drought stress

Changes in stem sugar content due to drought stress imposed at the early reproductive stage were studied in seven genotypes of sorghum differing in their ability to store stem sugar. Out of the seven genotypes, two genotypes (ICSSH 58 and SPV 1411) that showed little variation in total sugar levels at the 5th internode from the peduncle on exposure to drought treatment and five genotypes (ICSV 25275, ICSV 25280, PVK801, RSSV 9 and M 35-1) that showed significant increases in total sugar levels on drought exposure, were grouped and used for comparative studies on sugar metabolism. Drought stress led to a decrease in sucrose synthase activity in the catabolic direction in both groups. However, neutral and acid invertase activities increased significantly in the genotypes ICSSH 58 and SPV 1411, and correlated to the increase in reducing sugar content on exposure to drought. Hydrolysis of stem sugars probably had a role to play in osmotic adjustment on exposure to drought stress and correlated to retention of sap volume in these genotypes. However the activities of sugar metabolizing enzymes did not correlate to their gene expression levels. On resuming irrigation after twenty days of drought stress and studying the yield parameters at physiological maturity stage, it was observed that grain yields, stalk yields and juice volume were lower in the plants recovering from drought stress as compared to the irrigated controls. In some genotypes like ICSV25275, ICSSH58 and M35-1, there were similar losses in grain yields and stem sugars due to the brief drought exposure, indicating source limitation of photoassimilates. However, in other genotypes like ICSV25280, PVK801 and RSSV9, grain yield losses were less than stem sugar losses in drought exposed plants as compared to controls, suggesting mobilization of sugars from the storage internodes to the developing panicle, to ensure viable progeny. Hence accumulation of stem sugars appears to be an adaptive strategy in some, but not all sorghum genotypes, against drought stress

Validation of cytoplasmic genetic male sterility in rabi sorghum hybrids and their parents using diagnostic set of microsatellite markers

Sorghum is an important cereal crop where cytoplasmic male sterility is exploited for hybrid breeding. Presently, A1 cytoplasm CGMS system has been well established because of the ease and stability of fertility restoration. Conventionally, genetic purity of hybrids is ensured by grow out test. In this context, DNA marker assisted selection technology offers an efficient alternative over traditionally grow out test especially in terms of time, environmental influence, space and cost-effective. Microsatellite markers are best suited for genetic purity assessment due to codominant nature

Membrane Topology and Predicted RNA-Binding Function of the ‘Early Responsive to Dehydration (ERD4)’ Plant Protein

Functional annotation of uncharacterized genes is the main focus of computational methods in the post genomic era. These tools search for similarity between proteins on the premise that those sharing sequence or structural motifs usually perform related functions, and are thus particularly useful for membrane proteins. Early responsive to dehydration (ERD) genes are rapidly induced in response to dehydration stress in a variety of plant species. In the present work we characterized function of Brassica juncea ERD4 gene using computational approaches. The ERD4 protein of unknown function possesses ubiquitous DUF221 domain (residues 312–634) and is conserved in all plant species. We suggest that the protein is localized in chloroplast membrane with at least nine transmembrane helices. We detected a globular domain of 165 amino acid residues (183–347) in plant ERD4 proteins and expect this to be posited inside the chloroplast. The structural-functional annotation of the globular domain was arrived at using fold recognition methods, which suggested in its sequence presence of two tandem RNA-recognition motif (RRM) domains each folded into βαββαβ topology. The structure based sequence alignment with the known RNA-binding proteins revealed conservation of two non-canonical ribonucleoprotein sub-motifs in both the putative RNA-recognition domains of the ERD4 protein. The function of highly conserved ERD4 protein may thus be associated with its RNA-binding ability during the stress response. This is the first functional annotation of ERD4 family of proteins that can be useful in designing experiments to unravel crucial aspects of stress tolerance mechanism

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