The bioinformatics challenges in comparative analysis of cereal genomes-an overview

Strategies to meet the global demand for natural food colorant bixin: A multidisciplinary approach

Bixin is an apocarotenoid derived from Bixa orellana L. well known as a food colorant along with its numerous industrial and therapeutic applications. With the current surge in usage of natural products, bixin has contributed immensely to the world carotenoid market and showcases a spike in its requirement globally. To bridge the gap between bixin availability and utility, owed to its bioactivity and demand as a colouring agent in industries the sustainable production of bixin is critical. Therefore, to meet up this challenge effective use of multidisciplinary strategies is a promising choice to enhance bixin quantity and quality. Here we report, an optimal blend of approaches directed towards manipulation of bixin biosynthesis pathway with an insight into the impact of regulatory mechanisms and environmental dynamics, engineering carotenoid degradation in plants other than annatto, usage of tissue culture techniques supported with diverse elicitations, molecular breeding, application of in silico predictive tools, screening of microbial bio-factories as alternatives, preservation of bixin bioavailability, and promotion of eco-friendly extraction techniques to play a collaborative role in promoting sustainable bixin production.

TriFLDB: a database of clustered full-length coding sequences from Triticeae with applications to comparative grass genomics

The Triticeae Full-Length CDS Database (TriFLDB) contains available information regarding full-length coding sequences (CDSs) of the Triticeae crops wheat (Triticum aestivum) and barley (Hordeum vulgare) and includes functional annotations and comparative genomics features. TriFLDB provides a search interface using keywords for gene function and related Gene Ontology terms and a similarity search for DNA and deduced translated amino acid sequences to access annotations of Triticeae full-length CDS (TriFLCDS) entries. Annotations consist of similarity search results against several sequence databases and domain structure predictions by InterProScan. The deduced amino acid sequences in TriFLDB are grouped with the proteome datasets for Arabidopsis (Arabidopsis thaliana), rice (Oryza sativa), and sorghum (Sorghum bicolor) by hierarchical clustering in stepwise thresholds of sequence identity, providing hierarchical clustering results based on full-length protein sequences. The database also provides sequence similarity results based on comparative mapping of TriFLCDSs onto the rice and sorghum genome sequences, which together with current annotations can be used to predict gene structures for TriFLCDS entries. To provide the possible genetic locations of full-length CDSs, TriFLCDS entries are also assigned to the genetically mapped cDNA sequences of barley and diploid wheat, which are currently accommodated in the Triticeae Mapped EST Database. These relational data are searchable from the search interfaces of both databases. The current TriFLDB contains 15,871 full-length CDSs from barley and wheat and includes putative full-length cDNAs for barley and wheat, which are publicly accessible. This informative content provides an informatics gateway for Triticeae genomics and grass comparative genomics. TriFLDB is publicly available at http://TriFLDB.psc.riken.jp/.

GA-20 oxidase as a candidate for the semidwarf gene sdw1/denso in barley

The barley sdw1/denso gene not only controls plant height but also yield and quality. The sdw1/denso gene was mapped to the long arm of chromosome 3H. Comparative genomic analysis revealed that the sdw1/denso gene was located in the syntenic region of the rice semidwarf gene sd1 on chromosome 1. The sd1 gene encodes a gibberellic acid (GA)-20 oxidase enzyme. The gene ortholog of rice sd1 was isolated from barley using polymerase chain reaction. The barley and rice genes showed a similar gene structure consisting of three exons and two introns. Both genes share 88.3% genomic sequence similarity and 89% amino acid sequence identity. A single nucleotide polymorphism was identified in intron 2 between barley varieties Baudin and AC Metcalfe with Baudin known to contain the denso semidwarf gene. The single nucleotide polymorphism (SNP) marker was mapped to chromosome 3H in a doubled haploid population of Baudin x AC Metcalfe with 178 DH lines. Quantitative trait locus analysis revealed that plant height cosegregated with the SNP. The sdw1/denso gene in barley is the most likely ortholog of the sd1 in rice. The result will facilitate understanding of the molecular mechanism controlling semidwarf phenotype and provide a diagnostic marker for selection of semidwarf gene in barley.

LegumeDB1 bioinformatics resource: comparative genomic analysis and novel cross-genera marker identification in lupin and pasture legume species

The identification of markers in legume pasture crops, which can be associated with traits such as protein and lipid production, disease resistance, and reduced pod shattering, is generally accepted as an important strategy for improving the agronomic performance of these crops. It has been demonstrated that many quantitative trait loci (QTLs) identified in one species can be found in other plant species. Detailed legume comparative genomic analyses can characterize the genome organization between model legume species (e.g., Medicago truncatula, Lotus japonicus) and economically important crops such as soybean (Glycine max), pea (Pisum sativum), chickpea (Cicer arietinum), and lupin (Lupinus angustifolius), thereby identifying candidate gene markers that can be used to track QTLs in lupin and pasture legume breeding. LegumeDB is a Web-based bioinformatics resource for legume researchers. LegumeDB analysis of Medicago truncatula expressed sequence tags (ESTs) has identified novel simple sequence repeat (SSR) markers (16 tested), some of which have been putatively linked to symbiosome membrane proteins in root nodules and cell-wall proteins important in plant-pathogen defence mechanisms. These novel markers by preliminary PCR assays have been detected in Medicago truncatula and detected in at least one other legume species, Lotus japonicus, Glycine max, Cicer arietinum, and (or) Lupinus angustifolius (15/16 tested). Ongoing research has validated some of these markers to map them in a range of legume species that can then be used to compile composite genetic and physical maps. In this paper, we outline the features and capabilities of LegumeDB as an interactive application that provides legume genetic and physical comparative maps, and the efficient feature identification and annotation of the vast tracks of model legume sequences for convenient data integration and visualization. LegumeDB has been used to identify potential novel cross-genera polymorphic legume markers that map to agronomic traits, supporting the accelerated identification of molecular genetic factors underpinning important agronomic attributes in lupin.

Genes controlling seed dormancy and pre-harvest sprouting in a rice-wheat-barley comparison

Pre-harvest sprouting results in significant economic loss for the grain industry around the world. Lack of adequate seed dormancy is the major reason for pre-harvest sprouting in the field under wet weather conditions. Although this trait is governed by multiple genes it is also highly heritable. A major QTL controlling both pre-harvest sprouting and seed dormancy has been identified on the long arm of barley chromosome 5H, and it explains over 70% of the phenotypic variation. Comparative genomics approaches among barley, wheat and rice were used to identify candidate gene(s) controlling seed dormancy and hence one aspect of pre-harvest sprouting. The barley seed dormancy/pre-harvest sprouting QTL was located in a region that showed good synteny with the terminal end of the long arm of rice chromosome 3. The rice DNA sequences were annotated and a gene encoding GA20-oxidase was identified as a candidate gene controlling the seed dormancy/pre-harvest sprouting QTL on 5HL. This chromosomal region also shared synteny with the telomere region of wheat chromosome 4AL, but was located outside of the QTL reported for seed dormancy in wheat. The wheat chromosome 4AL QTL region for seed dormancy was syntenic to both rice chromosome 3 and 11. In both cases, corresponding QTLs for seed dormancy have been mapped in rice.