Biology subjects

Kaur, J.

Publications and source records attributed to Kaur, J..

58 records · Page 4Linked to original sources

bioRxiv2019

Overlapping transcriptional expression response of wheat zinc-induced facilitator-like transporters emphasize important role during Fe and Zn stress

BackgroundHexaploid wheat is an important cereal crop that has been targeted to enhance grain micronutrient content including zinc and iron. In this direction, modulating the expression of plant transporters involved in Fe and Zn homeostasis could be one of the promising approaches. Therefore, the present work was undertaken to identify bread wheat Zinc-Induced Facilitator-Like (ZIFL) family of transporters and study their transcriptional expression response during micronutrient fluctuations and exposure to multiple heavy metals.\n\nResultsThe genome-wide analyses resulted in identification of thirty-five putative TaZIFL genes, which were distributed only on Chromosome 3, 4 and 5. Wheat ZIFL proteins subjected to the phylogenetic analysis showed the uniform distribution along with rice, Arabidopsis and maize. In-silico analysis of the promoters of the wheat ZIFL genes suggested the presence of multiple metal binding sites including those which are involved in Fe homeostasis. QRT-PCR analysis of wheat ZIFL genes suggested the differential regulation of the transcripts in roots and shoots under surplus Zn and also during Fe starvation. Specifically, in roots, TaZIFL2.3, TaZIFL4.1, TaZIFL4.2, TaZIFL5, TaZIFL6.1 and TaZIFL6.2 were significantly up-regulated by both Zn and Fe. This suggested that ZIFL could possibly be regulated by both the nutrient stress in a tissue specific manner. Interestingly, upon exposure to heavy metals, TaZIFL4.2 and TaZIFL7.1 showed significant up-regulation, whereas TaZIFL5 and TaZIFL6.2 remained almost unaffected.\n\nConclusionThis is the first report with detailed analysis of wheat ZIFL genes. Our study also identifies closest ortholog for transporter of mugineic acid, a chelator required for Fe uptake. Comprehensive transcript expression pattern during development of wheat seedlings and against various abiotic/biotic stresses resulted in tissue specific responses. Overall, this work addresses the role of wheat ZIFL during the interplay between micronutrient and heavy metal stress in a tissue specific manner.

plant biology↗

bioRxiv2019

ROS accumulation and associated cell death mediates susceptibility to Alternaria brassicae in Arabidopsis accessions

Alternaria brassicae is a necrotrophic fungal pathogen capable of infecting most of the agriculturally important Brassica species. The mechanisms underlying invasion of A. brassicae and host responses are unknown. In the present study, we exploited the natural variation in Arabidopsis to understand the molecular and cellular mechanisms underlying resistance to A. brassicae. Using a subset of resistant (Ei-2, Ull2-3, Lz-0, and Cvi-0) and susceptible (Gre-0, Est-1, and Zdr1) accessions, we show that the susceptibility to A. brassicae is associated with higher ROS accumulation and cell death. Susceptibility to A. brassicae was reduced in the rboh (D, E and F) mutants that are incapable of producing ROS, suggesting that RBOH D, E and F may act as negative regulators of defence against this pathogen. Additionally, our data also supports the hypothesis that the Jasmonic acid (JA), Ethylene (ET) and Abscisic acid (ABA) signalling pathways positively contribute to resistance against necrotrophic pathogens. In summary, these results reveal the central role of ROS and cell death in the pathogenesis of A. brassicae and expand our understanding of plant-necrotroph interactions.

plant biology↗

bioRxiv2019

Genome-wide expression analysis identifies core components during iron starvation in hexaploid wheat

Iron is one of essential micronutrient for all organisms. Its deficiency causes a severe loss in crops yield. Nevertheless, our current understanding on major crops response to Fe deficiency remains limited. Herein, we investigated the effect of Fe deprivation at both transcriptomic and metabolic levels in hexaploid wheat. A genome-wide gene expression reprogramming was observed with a total of 5854 genes showing differential expression in roots of wheat subjected to Fe-starved medium. Subsequent, analysis revealed a predominance of strategy-II mode of Fe uptake, with induced genome bias contribution from the A and B genomes. In general, the predominance of genes encoding for nicotianamine synthase, yellow stripe like transporters, metal transporters, ABC transporters and zinc-induced facilitator-like protein was noticed. Our transcriptomic data were in agreement with the GC-MS analysis that showed an enhancement of accumulation of various metabolites such as fumarate, malonate, succinate and xylofuranose, which could be linked for enhancing Fe-mobilization. Interestingly, Fe starvation causes a significant temporal increase of glutathione-S-transferase both at transcriptional and enzymatic activity, which indicate the important role of glutathione in the response to Fe starvation in wheat roots. Taken together, our result provides new insight on wheat response to Fe starvation and lays foundation to design strategies to improve Fe nutrition in crops.

plant biology↗

bioRxiv2018

Pervasive transcription-dependent chromatin remodeling influences the replication initiation program

In Eukaryotic organisms, replication initiation follows a temporal program. Among the parameters that regulate this program in Saccharomyces cerevisiae, chromatin structure has been at the center of attention without considering the contribution of transcription. Here, we revisit the replication initiation program in the light of pervasive transcription. We find that noncoding RNA transcription termination in the vicinity of replication origins or ARS (Autonomously Replicating Sequences) maximizes replication initiation by restricting transcriptional readthrough into ARS. Consistently, high natural nascent transcription correlates with low ARS efficiency and late replication timing. High readthrough transcription is also linked to chromatin features such as high levels of H3K36me3 and deacetylated nucleosomes. Moreover, forcing ARS readthrough transcription promotes these histone modifications. Finally, replication initiation defects induced by increased transcriptional readthrough are partially rescued in the absence of H3K36 methylation. Altogether, these observations indicate that natural pervasive transcription into ARS influences replication initiation through chromatin remodeling.

molecular biology↗