Organogenesis induction in rice callus by cyanobacterial extracellular product

Cyanobacteria or blue green algae are prokaryotic photosynthetic microorganism that produces a wide array of substances, including plant growth regulators. In the case of growth regulators, gibberellin, auxin, cytokinin, ethylene, abscisic acid and jasmonic acid have been detected in cyanobacteria. Many substances have been added to plant tissue culture media in order to promote plant regeneration. The present research communication gives a report of the study of the effect of extracellular products of Plectonema sp., isolated from paddy fields on regeneration of rice. The endosperm of three rice varieties, IR 50, ASD 16 and ADT 36, were used as explants. IR 50 showed earlier and good callus induction response in MS medium. For root induction, cyanobaterial extracellular product was added instead of 2,4-D. The result showed that the number of days taken for root initiation and root growth was quicker by adding the extracellular products. Interestingly, more proliferation of roots in cyanobaterial extracellular product treatments was also observed compared to 2,4-D which might due to the production of growth regulators like auxin(s). Tremendous growth of root length and volume in short period indicate that MS with cyanobaterial extracellular product may also be used for screening of rice genotypes for water stress condition.Keywords: Callus induction, cyanobacterial extracellular products, Plectonema sp., rice, root inductio

Comparative gene expression analysis of susceptible and resistant near-isogenic lines in common wheat infected by Puccinia triticina

Gene expression after leaf rust infection was compared in near-isogenic wheat lines differing in the Lr10 leaf rust resistance gene. RNA from susceptible and resistant plants was used for cDNA library construction. In total, 55 008 ESTs were sequenced from the two libraries, then combined and assembled into 14 268 unigenes for further analysis. Of these ESTs, 89% encoded proteins similar to (E value of < or =10(-5)) characterized or annotated proteins from the NCBI non-redundant database representing diverse molecular functions, cellular localization and biological processes based on gene ontology classification. Further, the unigenes were classified into susceptible and resistant classes based on the EST members assembled from the respective libraries. Several genes from the resistant sample (14-3-3 protein, wali5 protein, actin-depolymerization factor and ADP-ribosylation factor) and the susceptible sample (brown plant hopper resistance protein, caffeic acid O-methyltransferase, pathogenesis-related protein and senescence-associated protein) were selected and their differential expression in the resistant and susceptible samples collected at different time points after leaf rust infection was confirmed by RT-PCR analysis. The molecular pathogenicity of leaf rust in wheat was studied and the EST data generated made a foundation for future studies

Comprehensive Functional Analyses of Expressed Sequence Tags in Common Wheat (Triticum aestivum)

About 1 million expressed sequence tag (EST) sequences comprising 125.3 Mb nucleotides were accreted from 51 cDNA libraries constructed from a variety of tissues and organs under a range of conditions, including abiotic stresses and pathogen challenges in common wheat (Triticum aestivum). Expressed sequence tags were assembled with stringent parameters after processing with inbuild scripts, resulting in 37 138 contigs and 215 199 singlets. In the assembled sequences, 10.6% presented no matches with existing sequences in public databases. Functional characterization of wheat unigenes by gene ontology annotation, mining transcription factors, full-length cDNA, and miRNA targeting sites were carried out. A bioinformatics strategy was developed to discover single-nucleotide polymorphisms (SNPs) within our large EST resource and reported the SNPs between and within (homoeologous) cultivars. Digital gene expression was performed to find the tissue-specific gene expression, and correspondence analysis was executed to identify common and specific gene expression by selecting four biotic stress-related libraries. The assembly and associated information cater a framework for future investigation in functional genomics

Variation in grain Zn concentration, and the grain ionome, in field-grown Indian wheat

Wheat is an important dietary source of zinc (Zn) and other mineral elements in many countries. Dietary Zn deficiency is widespread, especially in developing countries, and breeding (genetic biofortification) through the HarvestPlus programme has recently started to deliver new wheat varieties to help alleviate this problem in South Asia. To better understand the potential of wheat to alleviate dietary Zn deficiency, this study aimed to characterise the baseline effects of genotype (G), site (E), and genotype by site interactions (GxE) on grain Zn concentration under a wide range of soil conditions in India. Field experiments were conducted on a diverse panel of 36 Indian-adapted wheat genotypes, grown on a range of soil types (pH range 4.5–9.5), in 2013–14 (five sites) and 2014–15 (six sites). Grain samples were analysed using inductively coupled plasma-mass spectrometry (ICP-MS). The mean grain Zn concentration of the genotypes ranged from 24.9–34.8 mg kg-1, averaged across site and year. Genotype and site effects were associated with 10% and 6% of the overall variation in grain Zn concentration, respectively. Whilst G x E interaction effects were evident across the panel, some genotypes had consistent rankings between sites and years. Grain Zn concentration correlated positively with grain concentrations of iron (Fe), sulphur (S), and eight other elements, but did not correlate negatively with grain yield, i.e. no yield dilution was observed. Despite a relatively small contribution of genotype to the overall variation in grain Zn concentration, due to experiments being conducted across many contrasting sites and two years, our data are consistent with reports that biofortifying wheat through breeding is likely to be effective at scale given that some genotypes performed consistently across diverse soil types. Notably, all soils in this study were probably Zn deficient and interactions between wheat genotypes and soil Zn availability/management (e.g. the use of Zn-containing fertilisers) need to be better-understood to improve Zn supply in food systems

Short Communication - Organogenesis induction in rice callus by cyanobacterial extracellular product

Cyanobacteria or blue green algae are prokaryotic photosynthetic microorganism that produces a wide array of substances, including plant growth regulators. In the case of growth regulators, gibberellin, auxin, cytokinin, ethylene, abscisic acid and jasmonic acid have been detected in cyanobacteria. Many substances have been added to plant tissue culture media in order to promote plant regeneration. The present research communication gives a report of the study of the effect of extracellular products of Plectonema sp., isolated from paddy fields on regeneration of rice. The endosperm of three rice varieties, IR 50, ASD 16 and ADT 36, were used as explants. IR 50 showed earlier and good callus induction response in MS medium. For root induction, cyanobaterial extracellular product was added instead of 2,4-D. The result showed that the number of days taken for root initiation and root growth was quicker by adding the extracellular products. Interestingly, more proliferation of roots in cyanobaterial extracellular product treatments was also observed compared to 2,4-D which might due to the production of growth regulators like auxin(s). Tremendous growth of root length and volume in short period indicate that MS with cyanobaterial extracellular product may also be used for screening of rice genotypes for water stress condition