Biology subjects

Muthamilarasan, M.

Publications and source records attributed to Muthamilarasan, M..

4 recordsLinked to original sources

bioRxiv2025

A BIOPOLYMER LAMINARIN ELICITS ANTIOXIDANT DEFENSE IN DIFFERENT CULTIVARS OF SOLANUM LYCOPERSICUM AGAINST EARLY BLIGHT DISEASE CAUSED BY ALTERNARIA SOLANI

The study evaluates the potential of laminarin (LaM), a biopolymer, in inducing antioxidative defense in tomato against early blight disease caused by Alternaria solani. Histological analysis of A. solani infection in susceptible (PKM-1) and tolerant (Arka Rakshak) cultivars of tomato showed increased pathogen colonization in PKM-1 by day 8 compared to Arka Rakshak. Fluorescent microscopic analysis with a chitin-specific dye, Calcofluor white, demonstrated reduced A. solani colonization in PKM-1 pretreated with LaM (0.1%), followed by A. solani infection on par with Arka Rakshak. A significant increase in the accumulation of hydrogen peroxide was observed in LaM-pretreated leaves (0.050%, 0.075% and 0.1%) at 24- and 48-hours post-infection in both cultivars. A quantitative increase in guaiacol peroxidase (GPX) activity was recorded in LaM (0.025%), followed by A. solani infection leaves at 36 hrs in Arka Rakshak, whereas LaM (0.010%) followed by A. solani infection recorded maximum GPX activity at 24 hrs in PKM-1. Induction of new GPX isoform was evident in LaM (0.075% and 0.1%) pretreated, and LaM pretreated, followed by A. solani infected leaves of both cultivars at 24 hrs. There was a significant reduction in disease severity in tomato leaves pretreated with LaM (0.1%) and infected with A. solani. The results suggest that LaM could be a potential elicitor of antioxidant defense in tomato against A. solani infection, which can further be harnessed to develop sustainable strategies for managing early blight disease while reducing dependence on chemical fungicides.

plant biology↗

bioRxiv2025

Comparative transcriptome analysis of tomato cultivars pretreated with Laminarin reveals differential expression of defense-responsive genes against Early blight disease

Eco-friendly measures to control disease progression are the need of the hour since chemical fungicides have been harmful to the environment. This study observed that the algal polysaccharide Laminarin triggers a defense response against early blight disease in both tolerant and susceptible tomato cultivars. A dose-dependent reduction in cell death was observed in tomato leaves pre-treated with 0.1% Laminarin and then infected with Alternaria solani in a susceptible and tolerant cultivar. As a result, 0.1% Laminarin was chosen for transcriptome analysis. Transcriptome analysis revealed the upregulation of defense-related genes, such as EF-hand domain-containing protein, Heat shock protein 70, Heat shock factor (HSF) type DNA binding domain-containing protein, Non-specific serine/threonine protein kinase, AP2/ERF domain-containing protein, Leucine-rich repeat-containing N-terminal plant type domain-containing protein, and Subtilisin-like protease. The study also validated the differentially expressed genes using qRT-PCR for bZIP, nsLTP, SKP1, and V-type ATPase genes. Overall, the study demonstrated that the algal polysaccharide Laminarin could induce defense-related genes and provide resistance against early blight disease in tomato plants. KEY MESSAGETomatoes defense-responsive genes showed differential expression in tolerant and susceptible cultivars when treated with laminarin, followed by Alternaria solani infection.

plant biology↗

bioRxiv2023

SiHDA9 interacts with SiHAT3.1 and SiHDA19 to repress dehydration responses through H3K9 deacetylation in foxtail millet

Drought stress affects the growth and productivity of plants, where C4 plants can advantageously perceive and respond to the stress for their survival and reproduction. Epigenetic modifications play a prominent role in conferring drought tolerance in C4 plants; however, the molecular links between histone modifiers and their regulation are unclear. In the present study, we performed a genome-wide H3K9ac enrichment in foxtail millet (Setaria italica) and analyzed their role in regulating the expression of drought-responsive genes. The presence of H3K9ac on these genes were identified through the comparative analysis of dehydration tolerant (cv. IC4) and sensitive (IC41) cultivars of foxtail millet. A histone deacetylase, SiHDA9, showed significant upregulation in the sensitive cultivar during dehydration stress. SiHDA9 overexpression in Arabidopsis thaliana conferred higher sensitivity to dehydration/drought stress than WT plants. We found that SiHDA9 physically interacts with SiHAT3.1 and SiHDA19. This complex is recruited through the SiHAT3.1 recognition sequence on the upstream of drought-responsive genes (SiRAB18, SiRAP2.4, SiP5CS2, SiRD22, SiPIP1;4, and SiLHCB2.3) to decrease H3K9 acetylation levels. The modulations in H3K9ac levels cause repression of gene expression and induce drought-sensitivity in the sensitive cultivar. Overall, the study provides mechanistic insights into SiHDA9-mediated regulation of drought stress response in foxtail millet.

plant biology↗

bioRxiv2019

Molecular characterization and differential expression reveal functional divergence of stress-responsive enzymes in C4 panicoid models, Setaria italica and Setaria viridis

Stress-responsive genes regulate the morpho-physiological as well as molecular responses of plants to environmental cues. In addition to known genes, there are several unknown genes underlying stress-responsive machinery. One such machinery is the sophisticated biochemical carbon-concentrating mechanism of the C4 photosynthetic pathway that enables the plants to survive in high temperatures, high light intensities and drought conditions. Despite the importance of C4 photosynthesis, no comprehensive study has been performed to identify and characterize the key enzymes involved in this process among sequenced Poaceae genomes. In the present study, five major classes of enzymes that are reported to play roles in C4 biochemical carbon-concentrating mechanism were identified in sequenced Poaceae genomes with emphasis on the model crops, Setaria italica and S. viridis. Further analysis revealed that segmental and tandem duplications have contributed to the expansion of these gene families. Comparative genome mapping and molecular dating provided insights into their duplication and divergence in the course of evolution. Expression profiling of candidate genes in contrasting S. italica cultivars subjected to abiotic stresses and hormone treatments showed distinct stress-specific upregulation of SiCaH1, Si{beta}CaH5, SiPEPC2, SiPPDK2, SiMDH8 and SiNADP-ME5 in the tolerant cultivar. Altogether, the study highlights key stress-responsive genes that could serve as potential candidates for elucidating their precise roles in stress tolerance. Key messageComprehensive analysis of stress-responsive gene families in C4 model plants, Setaria italica and S. viridis identified SiCaH1, SiPEPC2, SiPPDK2, SiMDH8 and SiNADP-ME5 as potential candidates for engineering abiotic stress tolerance.

plant biology↗