53 research outputs found
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No full textNot AvailableRice is one of the most important cereals crops with great potential for improvement through biotechnological intervention. Agrobacterium-mediated transformation method for rice has been well established. In the transformation method, antibiotic resistant gene of hpt is routinely used as a powerful marker for transgenic rice plants selection. In this study, the hygromycin sensitivity test was executed on wild type Pusa Sugandh 2 (PS2) seeds, based on mesocotyl length, root development and leaf color, the most efficient optimal concentration of hygromycin 50mg/L was used for selection of the transgenic seeds and leaf assay. Wild type seedlings revealed reduction in mesocotyls lengths, root elongation and bleached leaf, as compared to transgenic seedlings on hygromycin selection media. Non-transgenic rice leaves (PS2) had phenotypic symptoms of necrosis, dark-brownish strips or bleached tips and entirely bleach out of lamina, while transgenic leaf remained green and healthy after one week of hygromycin selection. Based on the above results, a simple, rapid, inexpensive, time-saving method for effective evaluation of transgenic progeny containing hpt gene using leaf and germination assay of transformed seeds are described. This study confirms an unambiguous differentiation between transgenic and non-transgenic plants.Not Availabl
Evolutionary Relationship and Structural Analysis of Blast Resistance Associated Novel Osvwa36 and Osvwa37 Genes in Cultivated and Wild Species of Rice
No full textRice blast is a dreadful disease that causes enormous losses in rice production worldwide. To develop blast resistant rice cultivars, it is necessary to identify resistance and defence regulator genes and the underlying mechanism of resistance. A novel von Willebrand factor domain A containing genes OsvWA36 and OsvWA37 in Tetep cultivar of rice regulate response to Magnaporthe oryzae infection and provides significant resistance. Owing to the important role of these genes, their evolutionary relationship has been studied in cultivated and wild species of rice. There is significant diversity in the protein sequence of these genes among the relative wild rice species. The size of OsvWA36 protein varies from 501 aa to 698 aa whereas size of OsvWA37 protein varies from 295 aa to 1004 aa. The, OsvWA36 gene is evolutionarily more conserved than OsvWA37 among the different rice species indicating its critical role. Besides the global variation in protein sequence, the region of vWA domain is highly conserved among all the species. Interestingly, both the genes in Oryza barthii are fused to form a single gene encoding a large protein that indicates their origin in other species from a single gene. The good quality tertiary structures of both OsvWA36 and OsvWA37 proteins in cultivated germplasm cv. Tetep were also generated which can be utilized for protein structural and docking studies
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No full textNot AvailableNext-generation sequencing (NGS) based virome analyses of mRNA and sRNA
have recently become a routine approach for reliable detection of plant viruses and
viroids. In the present study we identified the viral/viroidal spectrum of several Indian
grapevine cultivars and reconstructed their whole genomes using the publically available
mRNAome and sRNAome datasets. Twenty three viruses and viroids (including two
variants of grapevine leafroll associated virus 4) were identified from two tissues (fruit
peels and young leaves) of three cultivars among which nine unique grapevine viruses
and viroids were identified for the first time in India. Irrespective of the assemblers
and tissues used, the mRNA based approach identified more acellular pathogens
than the sRNA based approach across cultivars. Further, the mRNAome was on
par with the whole transcriptome in viral identification. Through de novo assembly of
transcriptomes followed by mapping against reference genome, we reconstructed 19
complete/near complete genomes of identified viruses and viroids. The reconstructed
viral genomes included four larger RNA genomes (>13 kb), a DNA genome (RG
grapevine geminivirus A), a divergent genome (RG grapevine virus B) and a genome
for which no reference is available (RG grapevine virus L). A large number of SNPs
detected in this study ascertained the quasispecies nature of viruses. Detection of
three recombination events and phylogenetic analyses using reconstructed genomes
suggested the possible introduction of viruses and viroids into India from several
continents through the planting material. The whole genome sequences generated in
this study can serve as a resource for reliable indexing of grapevine viruses and viroids
in quarantine stations and certification programs.Not Availabl
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No full textNot AvailableRice provides staple food for a large part of the world’s human population. Abiotic stresses, such as salinity, heat and low temperature stimulates diverse morphological, physiological and biochemical responses that negatively impact the plant growth, development and productivity of crops. Screening of rice genotypes against abiotic stress is a fundamental step to understand the mechanism and stress tolerance of rice cultivars. Two indica rice cv Nagina22 (N22) and Pusa Sugandh2 (PS2) were screened for salt (150mM NaCl), cold (12°C) and heat (40°C) stress responses through morpho-physiological and biochemical traits at the seedling stage. FL478 and MTU1010 varieties were used as salt and cold tolerant control, respectively. The present investigation showed salinity and cold tolerance of PS2 was noticeable through lower reduction in fresh and dry weight of seedlings, photosynthetic pigments and associated with higher accumulation of proline, lower ion leakage and MDA content under salinity and cold stresses. In contrast, under high temperature treatment, PS2 genotype had significantly higher reduction of biomass and photosynthetic pigments, less cell membrane stability, higher lipid peroxidation, and lower proline accumulation as compared to N22. From our study, PS2 was found to be tolerant to cold and salinity stress, while N22 was found to be tolerant to heat stress. Evaluation of abiotic stress tolerance at seedling stage against salt, cold and heat stresses by utilizing morphological, physiological and biochemical approaches is an appropriate way in rice, when used along with suitable check variety.Not Availabl
Understanding the role of miRNAs in governing the drought sensitive response of a rice mega variety, Swarna at reproductive stage
No full textTo combat drought stress, the major abiotic stress in rice, major genomic regions governing stress tolerance under field conditions have been identified and exploited, though their molecular basis remains elusive till date. We have recently reported the miRNAs/mRNA modules important for drought stress response in these genomic regions. To further understand this secondary regulation by miRNA/mRNA modules in a mega variety, Swarna, which is sensitive to drought stress at reproductive stage, we generated sRNA-seq data. Our analysis identified 9 putative novel miRNAs and 27 differentially expressed known miRNAs at booting stage under drought stress. The major miRNA/transcript modules, identified through degradome analysis and transcript abundance studies, that had an impact on drought stress response of plant and yield included osa-miR169a/LOC_Os07g41720, Osa-miR171b/f, Osa-miR172d-3p/5p, Osa-miR1876/ LOC_Os11g38330, Osa-miR397a and Osa-miR530–3p. The results indicated a basis for the low spikelet fertility and high grain chalkiness of the mega variety Swarna under drought stress through the modulation of expression of Osa-miR397a/ LOC_Os03g03510 and LOC_Os03g51220 and Osa-miR530–3p/ LOC_Os10g40510 modules. This study provides the potential target genes for improving Swarna, a globally important variety, so as to ensure food security under climate change scenario
Genetic variability, heritability, and trait associations in gladiolus (Gladiolus grandiflorus L.) genotypes
No full textThis study evaluated genetic variability, heritability, genetic advance and trait associations among gladiolus genotypes at ICAR-IARI, New Delhi, India, from 2022 to 2024. The study implemented a randomized block design with three replications. ANOVA revealed highly significant differences among genotypes, with genotypic effects most contributing to the total variance. Phenotypic variation exceeded genotypic variation, although environmental influence was minimal. High heritability coupled with high genetic advance was observed for cormel weight per hill (94.56%, 206.55%), cormel number per hill (91.73%, 189.62%), plant height (87.39%, 41.23%), spike length, and rachis length, indicating additive gene action and scope for direct selection. Correlation and PCA analyses confirmed strong associations among key traits and clear genotype differentiation, with G. callianthus being distinct. Promising genotypes included Rose Supreme, Chirag, Snow Princess and Dhanvantri. These findings provide a foundation for targeted breeding to develop improved cultivars with enhanced yield and floral quality and guide future research
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No full textNot AvailableThe nitrogen use efficiency (NUE) of crop plants is limited and enhancing it in rice,
a major cereal crop, would be beneficial for farmers and the environment alike. Here we report the
genome-wide transcriptome analysis of two rice genotypes, IR 64 (IR64) and Nagina 22 (N22) under
optimal ( + N ) and chronic starvation ( -N ) of nitrogen (N) from 15-day-old root and shoot tissues.
The two genotypes were found to be contrasting in their response to -N; IR64 root architecture
and root dry weight remained almost equivalent to that under + N conditions, while N22 showed
high foraging ability but a substantial reduction in biomass under -N. Similarly, the photosynthetic
pigments showed a drastic reduction in N22 under low N, while IR64 was more resilient. Nitrate
reductase showed significantly low specific activity under -N in both genotypes. Glutamate synthase
(GOGAT) and citrate synthase CS activity were highly reduced in N22 but not in IR64. Transcriptome
analysis of these genotypes revealed nearly double the number of genes to be differentially expressed
(DEGs) in roots (1016) compared to shoots (571). The response of the two genotypes to N starvation
was distinctly different reflecting their morphological/biochemical response with just two and
eight common DEGs in the root and shoot tissues. There were a total of 385 nitrogen-responsive DEGs
(106 in shoots and 279 in roots) between the two genotypes. Fifty-two of the 89 DEGs identified as
specific to N22 root tissues were also found to be differentially expressed between the two genotypes
under -N. Most of these DEGs belonged to starch and chloroplast metabolism, followed by membrane
and signaling proteins. Physical mapping of DEGs revealed 95 DEGs in roots and 76 in shoots to be
present in quantitative trait loci (QTL) known for NUE.Not Availabl
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No full textNot AvailableDeeper Rooting 1 (DRO1) gene identified from a major QTL on chromosome 9 increases the root growth angle (RGA) and thus facilitates survival under drought and hence is an excellent candidate for rice improvement. Twenty-four major Indian upland and lowland genotypes including the ‘yield under drought’ (DTY) QTL donors were subjected to allele mining of DRO1 (3058 bp) using four pairs of overlapping primers. A total of 216 and 52 SNPs were identified across all genotypes in the gene and coding region (756 bp) respectively with transversions 3.6 fold more common than transitions in the gene and 2.5 times in the CDS. In 251 amino acid long protein, substitutions were found in 19 positions, wherein change in position 92 was the most frequent. Based on allele mining, the 24 genotypes can be classified into 16 primary structure variants ranging from complete functional allele (Satti, IR36 and DTY 3.1 donor, IR81896-B-B-195) to truncated non-functional alleles in PMK2, IR64, IR20 and Swarna. All the DTY donors, other than IR81896-B-B-195, and most of the upland drought tolerant cultivars (Nagina 22, Vandana and Dhagaddeshi) had accumulated 6–19 SNPs and 4–8 amino acid substitutions resulting in substantial differences in their protein structure. The expression analysis revealed that all the genotypes showed upregulation under drought stress though the degree of upregulation varied among genotypes. The information on structural variations in DRO1 gene will be very useful for the breeders, especially in the light of recent breeding programmes on improving drought tolerance using several DTY donors and upland accessions
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