A plant's response to stress conditions is governed by intricately coordinated gene expression. The microRNAs (miRs) have emerged as relatively new players in the genetic network, regulating gene ...expression at the transcriptional and post-transcriptional level. In this study, we performed comprehensive profiling of miRs in roots of the naturally salt-tolerant Pokkali rice variety to understand their role in regulating plant physiology in the presence of salt. For comparisons, root miR profiles of the salt-sensitive rice variety Pusa Basmati were generated. It was seen that the expression levels of 65 miRs were similar for roots of Pokkali grown in the absence of salt (PKNR) and Pusa Basmati grown in the presence of salt (PBSR). The salt-induced dis-regulations in expression profiles of miRs showed controlled changes in the roots of Pokkali (PKSR) as compared to larger variations seen in the roots of Pusa Basmati. Target analysis of salt-deregulated miRs identified key transcription factors, ion-transporters, and signaling molecules that act to maintain cellular Ca
homeostasis and limit ROS production. These miR:mRNA nodes were mapped to the Quantitative trait loci (QTLs) to identify the correlated root traits for understanding their significance in plant physiology. The results obtained indicate that the adaptability of Pokkali to excess salt may be due to the genetic regulation of different cellular components by a variety of miRs.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The monopartite Chili leaf curl virus (ChiLCV) and its beta-satellite (ChiLCB) have been found to co-exist in infected plants. The ability of betaC1 protein to suppress RNA silencing was investigated ...using an in-house developed in-planta reversal of silencing assay, using Nicotiana tabacum lines harboring green fluorescent protein (GFP) silenced by short hairpin GFP (.sub.ShGFP). Transient expression of recombinant betaC1 complemented and increased the suppressor activity of ChiLCV coat protein (CP), and this was confirmed by molecular analysis. In silico analysis followed by a yeast two-hybrid screen-identified ChiLCV-CP as the interacting partner of the ChiLCB-betaC1 protein. Subcellular localization through confocal analysis revealed that when betaC1 and ChiLCV-CP were co-present, the fluorescence was localized in the cytoplasm indicating that nuclear localization of both proteins was obstructed. The cytoplasmic compartmentalization of the two viral suppressors of RNA silencing may be responsible for the enhanced suppression of the host gene silencing. This study presents evidence on the interaction of ChiLCV-CP and betaC1 proteins and indicates that ChiLCB may support the ChiLCV in overcoming host gene silencing to cause Chili leaf curl disease.
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CEKLJ, DOBA, EMUNI, FZAB, GEOZS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Salt tolerance is an important trait that is required to overcome salinity-induced reduction in plant productivity. We have reported previously the isolation of a pea DNA helicase 45 (PDH45) that ...exhibits striking homology with the eukaryotic translation initiation factor eIF-4A. Here, we report that PDH45 mRNA is induced in pea seedlings in response to high salt, and its overexpression driven by a constitutive cauliflower mosaic virus-35S promoter in tobacco plants confers salinity tolerance, thus suggesting a previously undescribed pathway for manipulating stress tolerance in crop plants. The T0transgenic plants showed high levels of PDH45 protein in normal and stress conditions, as compared with WT plants. The T0transgenics also showed tolerance to high salinity as tested by a leaf disk senescence assay. The T1transgenics were able to grow to maturity and set normal viable seeds under continuous salinity stress without any reduction in plant yield in terms of seed weight. Measurement of Na+ions in different parts of the plant showed higher accumulation in the old leaves and negligible accumulation in seeds of T1transgenic lines as compared with the WT plants. The possible mechanism of salinity tolerance is discussed. Overexpression of PDH45 provides a possible example of the exploitation of DNA/RNA unwinding pathways for engineering salinity tolerance without affecting yield in crop plants.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
RNA silencing is as an adaptive immune response in plants that limits the accumulation or spread of invading viruses. Successful virus infection entails countering the RNA silencing machinery for ...efficient replication and systemic spread in the host. The viruses encode proteins with the ability to suppress or block the host silencing mechanism, resulting in severe pathogenic symptoms and diseases. Tungro is a viral disease caused by a complex of two viruses and it provides an excellent system to understand the host and virus interactions during infection. It is known that Rice tungro bacilliform virus (RTBV) is the major determinant of the disease while Rice tungro spherical virus (RTSV) accentuates the symptoms. This study brings to focus the important role of RTBV ORF-IV in disease manifestation, by acting as both the victim and silencer of the RNA silencing pathway. The ORF-IV is a weak suppressor of the S-PTGS or stable silencing, but its suppression activity is augmented in the presence of specific RTSV proteins. Among these, RTBV ORF-IV and RTSV CP3 proteins interact with each other. This interaction may lead to the suppression of localized silencing as well as the spread of silencing in the host plants. The findings present a probable mechanistic glimpse of the requirement of the two viruses in enhancing tungro disease.
ARMOUR was developed as A Rice miRNA:mRNA interaction resource. This informative and interactive database includes the experimentally validated expression profiles of miRNAs under different ...developmental and abiotic stress conditions across seven Indian rice cultivars. This comprehensive database covers 689 known and 1664 predicted novel miRNAs and their expression profiles in more than 38 different tissues or conditions along with their predicted/known target transcripts. The understanding of miRNA:mRNA interactome in regulation of functional cellular machinery is supported by the sequence information of the mature and hairpin structures. ARMOUR provides flexibility to users in querying the database using multiple ways like known gene identifiers, gene ontology identifiers, KEGG identifiers and also allows on the fly fold change analysis and sequence search query with inbuilt BLAST algorithm. ARMOUR database provides a cohesive platform for novel and mature miRNAs and their expression in different experimental conditions and allows searching for their interacting mRNA targets, GO annotation and their involvement in various biological pathways. The ARMOUR database includes a provision for adding more experimental data from users, with an aim to develop it as a platform for sharing and comparing experimental data contributed by research groups working on rice.
The phylogeny and evolution of the microRNA families, miR820 and miR396
,
was analysed across the AA genomes of the
Oryza
species, the close relatives of domesticated rice. A highly dynamic evolution ...of the miR820 family was revealed. The number of copies of
MIR820
genes, their chromosomal location and the mature microRNA sequence varied greatly with a total of 16 novel miR820 variants being identified. The phylogeny of pre-
MIR820
sequences revealed that
MIR820
genes of recently evolved
Oryza
AA genomes may have derived from sequence divergence of one or a few ancestral genes found in wild Australian perennial rice populations, Taxon B (jpn2)-
MIR820
genes. Genomic scale duplication played an important role in the evolution of some of the miR396 family genes in AA genome
Oryza
species. miR396 family contained a
MIR396
gene cluster (
MIR396a
and
MIR396c
) which was conserved across the cereal genomes. Nucleotide diversity analysis at these two
MIR396
loci revealed that domesticated rice has retained less than 10% of the total diversity present in wild species. In contrast, the nucleotide sequence of four
MIR396
loci remained almost conserved across domesticated and wild rices, indicating that they were under extreme functional constraint and may be involved in regulating some fundamental processes which are important both for wild and domesticated rices. Expression analysis demonstrated that miR820 variants were expressed in
O. glaberrima O. barthi
and
O. longistaminata
genome. These findings pose new challenges to explain the possible role of miR820 variants identified.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
In the recent years, glyoxalase pathway has been an active area of research in both human
and plants. This pathway is reported to confer stress tolerance in plants, by modulating the glutathione
...homeostasis to achieve detoxification of a potent cytotoxic and mutagenic compound, methylglyoxal.
The microRNAs (miRNAs) are also reported to play significant role in stress tolerance for
plants. However, the cross-talk of miRNAs with the metabolism regulated by glyoxalase in the salinity-
tolerance is unexplored. We therefore investigated whether expression profiles of miRNAs are altered
in response to glyoxalase overexpression, and if any of these are also responsible for modulating
the stress responses of plants. In this study, the Next Generation Sequencing (NGS) was employed
to profile miRNA expression levels from glyoxalase overexpressing transgenic lines. The associated
targets of differentially expressed miRNAs were predicted and their functional annotation
was carried out using Gene Ontology (GO) and KEGG Orthology (KO), which showed their involvement
in several crucial biological pathways. The analysis of NGS datasets also identified other
isoforms or isomiRs of selected miRNAs, which may have an active role in developing tolerance
against salt stress. Different aspects of miRNA modifications were also studied in glyoxalase overexpressing
lines.
We report here the effect of antibiotics on the regeneration potential of recalcitrant indica rice cultivar, IR64. Different protocols reporting high-efficiency agro-bacterium-mediated transformation ...of mature seed-derived regenerative calli were used and compared. The putative transgenic (T0) plants were analyzed for integration of the transgene through polymerase chain reaction and Southern blotting analyses. It was observed that the high-efficiency transformation of scutellar-derived regenerative calli could be obtained by using maltose as a carbon source and increased quantity of 2,4-D on a medium containing a higher concentration of gelling agent. The percentage of regeneration is greatly affected by the presence of antibiotics.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Drought and water stress impose major limitations to crops, including Maize, as they affect the plant biology at multiple levels. Drought activates the cellular signalling machinery to maintain the ...osmotic and ROS homeostasis for controlling plant response and adaptation to stress. Molecular priming of seeds plays a significant role in imparting stress tolerance by helping plants to remember the stress, which improves their response when they encounter stress again.
In this study, we examined the effect of priming maize seeds with H
O
and proline, individually or in combination, on response to drought stress. We investigated the role of molecular priming on the physiological, biochemical and molecular response of maize seedlings during drought stress.
We observed that seed-priming played a significant role in mediating stress tolerance of seedlings under drought stress as indicated by changes in growth, biochemical properties, pigment and osmolyte accumulation, antioxidant enzyme activities, gas exchange parameters and gene expression. Seed-priming resulted in reduced expression of specific miRNAs to increase target transcripts associated with synthesis of osmolytes and maintenance of ROS homeostasis for reducing potential damage to the cellular components.
Seed-priming induced changes in the growth, biochemical properties, pigment and osmolyte accumulation, antioxidant enzyme activities, gas exchange parameters and gene expression, though the response was dependent on the genotype, as well as concentration and combination of the priming agents.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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![Interaction between [beta]C...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0175-7598/small "Interaction between [beta]C1 of satellite and coat protein of Chili leaf curl virus plays a crucial role in suppression of host RNA silencing")
