Publications of NIPGR Scientists

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Subject: search.filters.subject.Triticum aestivum

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    Stage-specific reprogramming of gene expression characterizes Lr48-mediated adult plant leaf rust resistance in wheat
    (Springer, 2015) Dhariwal, Raman; Gahlaut, Vijay; Govindraj, Bhaganagare R.; Singh, Dharmendra; Mathur, Saloni; Vyas, Shailendra; Bandopadhyay, Rajib; Khurana, Jitendra Paul; Tyagi, Akhilesh K.; Prabhu, Kumble Vinod; Mukhopadhyay, Kunal; Balyan, Harindra Singh; Gupta, Pushpendra Kumar
    Wheat genotype CSP44 carrying a recessive gene Lr48 exhibits adult plant resistance (APR; incompatible reaction) but gives a compatible reaction (susceptibility) at the seedling stage against leaf rust. A comparative gene expression analysis involving cDNA-amplified fragment length polymorphism (cDNA-AFLP) and quantitative PCR (qPCR) was carried out for incompatible and compatible reactions in the genotype CSP44. cDNA-AFLP analysis was conducted using RNA samples that were isolated from flag leaves following inoculation with leaf rust race 77-5 (the most virulent race) and also after mock inoculation. As many as 298 of a total of 493 expressed transcript-derived fragments (TDFs) exhibited differential expression (262 upregulated and 36 downregulated). Of these 298 TDFs, 48 TDFs were eluted from gels, re-amplified, cloned, and sequenced. Forty two of these 48 TDFs had homology with known genes involved in the following biological processes: energy production, metabolism, transport, signaling, defense response, plant-pathogen interaction, transcriptional regulation, translation, and proteolysis. The functions of the remaining six TDFs could not be determined; apparently, these represented some novel genes. The qPCR analysis for 18 TDFs (with known and unknown functions, but showing major differences in expression) was conducted using RNA isolated from the seedlings as well as from the adult plants. The expression of at least 11 TDFs was induced and that of 4 other TDFs attenuated or remained near normal in adult plants following leaf rust inoculations. The remaining three TDFs had non-specific/developmental stage-specific expression. Functional annotation of TDFs that were upregulated suggest that the APR was supported by transient recruitment and reprogramming of processes like perception and recognition of pathogen effector by receptors, followed by CDPK and MAPK signaling, transport, metabolism, and energy release.
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    Transcript profiling identifies novel transcripts with unknown functions as primary response components to osmotic stress in wheat (Triticum aestivum L.)
    (Springer, 2013) Garg, Bharti; Puranik, Swati; Misra, Shrilekha; Tripathi, Bhumi Nath; Prasad, Manoj
    Osmotic stress induced by dehydration and salinity, is among the major abiotic stresses that adversely impacts crop productivity and plants often display cultivar-dependent response against osmotic imbalance. To better understand the molecular mechanisms underlying differential responses to dehydration, transcriptome changes of two contrasting wheat (Triticum aestivum L.) cultivars were evaluated in plants grown under unfavorable osmotic conditions. A total of 107 non-redundant transcripts were identified. Of these, most had unknown functions (31; ~30 %) signifying the existence of putative stress-specific genes in wheat, reported here for the first time. Upon comparing with previous transcriptomic studies, 43 (40 %) of the osmotically-responsive transcripts were found not to be documented. These new transcripts may therefore signify unexplored gene sources for specific responses towards short-term osmotic stress in wheat. Through macroarray analysis, 69 (~64 %) transcripts were found to be differentially expressed (≥3-fold) and expression of 14 transcripts (with known or unknown functions) was further confirmed by quantitative real time PCR. Expression analysis of the seven unknown transcripts also revealed their tissue- and stress-specific regulation. Comparative in silico mapping of these 107 wheat transcripts against available mapping data for rice (40; ~37 %), maize (34; ~32 %), and sorghum (33; ~31 %) revealed presence of wheat orthologous sequences in these cereal crops. This study provides an interesting account on several novel genes, besides those with known functions, which may regulate stress response dynamics and thus, may be used as potential candidates to improve stress adaptability through genetic and molecular studies.
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    Abiotic stress-responsive expression of wali1 and wali5 genes from wheat
    (Landes Bioscience, 2012) Garg, Bharti; Puranik, Swati; Tuteja, Narendra; Prasad, Manoj
    Two cDNA clones, encoding Aluminum-responsive wali1 and wali5, were identified in dehydration stress-specific cDNA library from wheat. Their sequence variations and structural dissimilarities indicated them to be non-homologous genes. Expression of both genes was induced by various abiotic stresses as well as in response to plant hormones and oxidative molecules. Further, they were expressed differentially in shoot and root tissues of wheat seedlings, their transcripts being specifically abundant in roots. Previously characterized as being only Aluminum treatment induced, this report proposes them as novel candidates for stress-responsive studies.
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    Variability in Indian bread wheat (Triticum aestivum L.) varieties differing in nitrogen efficiency as assessed by microsatellite markers
    (Springer, 2010) Chandna, Ruby; Gupta, Sarika; Ahmad, Altaf; Iqbal, Muhammad; Prasad, Manoj
    Wheat (Triticum aestivum L.) is a staple food for half of the world. Its productivity and agronomical practices, especially for nitrogen supplementation, is governed by the nitrogen efficiency (NE) of the genotypes. We analyzed 16 popular cultivated Indian varieties of wheat for their NE and variability estimates using a set of 21 simple sequence repeat (SSR) markers, derived from each wheat chromosome. These genotypes were categorized into three groups, viz., low, moderate, and high nitrogen efficient. Of these 16 genotypes, we have reported six, eight, and two genotypes in high, moderate, and low NE categories, respectively. The differential NE in these genotypes was supported by nitrogen uptake and assimilation parameters. The values of average polymorphic information content and marker index for these SSR markers were estimated to be 0.32 and 0.59, respectively. The genetic similarity coefficient for all possible pairs of varieties ranged from 0.41 to 0.76, indicating the presence of considerable range of genetic diversity at molecular level. The dendrogram prepared on the basis of unweighted pair-group method of arithmetic average algorithm grouped the 16 wheat varieties into three major clusters. The clustering was strongly supported by high bootstrap values. The distribution of the varieties in different clusters and subclusters appeared to be related to their variability in NE parameter that was scored. Genetically diverse parents were identified that could potentially be used for their desirable characteristics in breeding programs for improvement of NE in wheat.
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    Crop breeding prospects in the genomic era
    (Taylor & Francis Group, 2006) Kumar, Sushil; Prasad, Manoj
    Grain/cereal crop yields need to be increased in the range of 5t ha 1, to meet the challenge of international food requirements, in the near future. Post-green revolution, conventional plant breeding and related procedures had limited success and grain crop yields have stagnated. The developments in plant genomics offer new means for genetic improvement in crop plants, such as transgenesis and marker aided precise selection of rare recombinants. A strategy, based on the use of existing genomic information on the genetic control of drought tolerance in Arabidopsis thaliana, for breeding wheat for high yields and drought tolerance is exemplified. In future plant breeding, the importance of systems approach, involving multidisciplinary contributions, to the understanding of gene structure Xenvironment interactions in respect of the concerned genes at whole plant or crop level is emphasized.