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Background: Gene upstream regularly sequences (URSs) can be used as one of the tools to annotate the biological functions of corresponding genes. In addition, tissue-preferred URSs are frequently used to drive the transgene expression exclusively in targeted tissues during plant transgenesis. Although many rice URSs have been molecularly characterized, it is still necessary and valuable to identify URSs that will benefit plant transformation and aid in analyzing gene function. Results: In this study, we identified and characterized root-, seed-, leaf-, and panicle-preferred genes on a genome-wide level in rice. Subsequently, their expression patterns were confirmed through quantitative real-time RT-PCR (qRT-PCR) by randomly selecting 9candidate tissue-preferred genes. In addition, 5 tissue-preferred URSs were characterized by investigating the URS::GUS transgenic plants. Of these URS::GUS analyses, the transgenic plants harboring LOC_Os03g11350 URS::GUS construct showed the GUS activity only in young pollen. In contrast, when LOC_Os10g22450 URS was used to drive the reporter GUS gene, the GUS activity was detected only in mature pollen. Interestingly, the LOC_Os10g34360 URS was found to be vascular bundle preferred and its activities were restricted only to vascular bundles of leaves, roots and florets. In addition, we have also identified two URSs from genes LOC_Os02G15090 and LOC_Os06g31070 expressed in a seed-preferred manner showing the highest expression levels of GUS activities in mature seeds. Conclusion: By genome-wide analysis, we have identified tissue-preferred URSs, five of which were further characterized using transgenic plants harboring URS::GUS constructs. These data might provide some evidence for possible functions of the genes and be a valuable resource for tissue-preferred candidate URSs for plant transgenesis. [ABSTRACT FROM AUTHOR]

Background: Biological scientists have long sought after understanding how genes and their structural/functional changes contribute to morphological diversity. Though both grain (BT×623) and sweet (Keller) sorghum lines originated from the same species Sorghum bicolor L., they exhibit obvious phenotypic variations. However, the genome re-sequencing data revealed that they exhibited limited functional diversity in their encoding genes in a genome-wide level. The result raises the question how the obvious morphological variations between grain and sweet sorghum occurred in a relatively short evolutionary or domesticated period. Results: We implemented an integrative approach by using computational and experimental analyses to provide a detail insight into phenotypic, genetic variation and expression diversity between BT×623 and Keller lines. We have investigated genome-wide expression divergence between BT×623 and Keller under normal and sucrose treatment. Through the data analysis, we detected more than 3,000 differentially expressed genes between these two varieties. Such expression divergence was partially contributed by differential cis-regulatory elements or DNA methylation, which was genetically determined by functionally divergent genes between these two varieties. Both tandem and segmental duplication played important roles in the genome evolution and expression divergence. Conclusion: Substantial differences in gene expression patterns between these two varieties have been observed. Such an expression divergence is genetically determined by the divergence in genome level. [ABSTRACT FROM AUTHOR]

Glutathione S-transferases (GSTs) exist in various eukaryotes and function in detoxification of xenobiotics and in response to abiotic and biotic stresses. We have carried out a genome-wide survey of this gene family in 10 plant genomes. Our data show that tandem duplication has been regarded as the major expansion mechanism and both monocot and dicot plants may have practiced different expansion and evolutionary history. Non-synonymous substitutions per site (Ka) and synonymous substitutions per site (Ks) analyses showed that N- and C-terminal functional domains of GSTs (GST_N and GST_C) seem to have evolved under a strong purifying selection (Ka/Ks < 1) under different selective pressures. Differential evolutionary rates between GST_N and GST_C and high degree of expression divergence have been regarded as the major drivers for the retention of duplicated genes and the adaptability to various stresses. Expression profiling also indicated that the gene family plays a role not only in stress-related biological processes but also in the sugar-signalling pathway. Our survey provides additional annotation of the plant GST gene family and advance the understanding of plant GSTs in lineage-specific expansion and species diversification. [ABSTRACT FROM PUBLISHER]