Biology subjects

Singh, P. D.

Publications and source records attributed to Singh, P. D..

3 recordsLinked to original sources

bioRxiv2026

Alternaria solani infection reprograms potato leaf metabolism and highlights potential defence and metabolic markers

Potato (Solanum tuberosum L.), the worlds fourth most cultivated crop, suffers yield losses of up to 40-50% from early blight caused by the necrotrophic fungal pathogen Alternaria solani. In this study we performed gas chromatography-mass spectrometry (GC-MS)-based untargeted metabolomics to characterize temporal alterations in metabolite composition, metabolic pathway regulation, and discriminatory biomarker metabolites in the susceptible Indian potato variety Kufri Jyoti, analyzing infected leaves, non-infected leaves, and lesion-associated necrotic tissues across four days post-inoculation (DPI).Metabolite annotation identified 58 compounds, including sugars, organic acids, amino acids, and secondary metabolites.. Multivariate analyses resolved distinct, largely non-overlapping metabolic clusters for control, infected leaves (1-4 DPI), and lesion tissue (Bs1-Bs3). A biphasic metabolic response was observed: early infection (1-2 DPI) was characterized by general suppression of primary metabolism, while late infection (3-4 DPI) showed pronounced upregulation of glycolysis, the TCA cycle, GS/GOGAT, and the shikimate pathway. Key discriminatory metabolites included asparagine, oxoproline, GABA, phenylalanine, and aromatic amino acids. Lesion tissues exhibited distinct metabolic fingerprints, with early disruption of amino acid recycling followed by a late rebound of defense-associated metabolites. Notably, defence-associated phenolics were detected exclusively within lesion tissue and were absent from whole-leaf profiles, demonstrating that spatially resolved lesion sampling captures defence chemistry that whole-leaf analysis alone would miss. The identified biomarker metabolites, particularly those linked to the shikimate and GS/GOGAT pathways, represent promising candidates for metabolite-assisted breeding and targeted crop protection strategies against early blight in potato. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=115 SRC="FIGDIR/small/745268v1_ufig1.gif" ALT="Figure 1"> View larger version (36K): org.highwire.dtl.DTLVardef@100dd28org.highwire.dtl.DTLVardef@1b78326org.highwire.dtl.DTLVardef@103578corg.highwire.dtl.DTLVardef@68b214_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗

bioRxiv2026

Decoding central metabolic rewiring induced by exogenous GABA shunt intermediates in Pea

O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=120 SRC="FIGDIR/small/741208v1_ufig1.gif" ALT="Figure 1"> View larger version (51K): org.highwire.dtl.DTLVardef@1b38bfborg.highwire.dtl.DTLVardef@ab10b6org.highwire.dtl.DTLVardef@d65370org.highwire.dtl.DTLVardef@ffe08b_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical AbstractC_FLOATNO C_FIG Legume-rhizobium symbiosis is constrained by carbon allocation and nutrient exchanges between the host plant and symbiotic bacteroids, emphasizing the necessity of biostimulant-based strategies to improve symbiotic efficiency. Studies suggest that plants provide carbon substrates (mainly TCA cycle intermediates) and nitrogen assimilation precursors to support bacteroid metabolism and nitrogen fixation. The GABA shunt represents a conserved bypass, linking the GS/GOGAT cycle, TCA cycle, and broader nitrogen metabolism. In the present study, the metabolic phenotypes upon rhizospheric application of exogenous {gamma}-aminobutyric acid (GABA) and succinate were investigated in pea. Application of exogenous GABA and succinate primarily altered the morpho-biochemical properties and root nodule establishment of the plant. While GABA supplementation reduced the root length and increased stomatal density, succinate treatment alone inhibited nodule organogenesis with disrupted symbiosome zoning. Metabolic rewirings associated with these phenotypic changes begin at the root nodule compartment, where exogenous GABA altered endogenous tricarboxylic acid (TCA) cycle pools, leading to higher turnover of TCA cycle intermediates, including succinate, fumarate, and malate, as well as elevated levels of sugars (sucrose, glucose, and fructose) and polyols (pinitol, mannitol, and myo-inositol). Concurrently, the plants accumulated substantially higher levels of asparagine (+3.9 log10-fold higher), accompanied by altered shoot protein content and enhanced elemental nitrogen content (+0.8-1%). Collectively, these findings demonstrate the potential of GABA as a biostimulant capable of altering the carbon-nitrogen dynamics and enhancing symbiotic functioning in pea root nodules, whereas succinate alters the process of nodule formation.

plant biology↗

bioRxiv2026

Drought induced metabolomics of potato leaves highlight metabolic reprogramming and promising biomarkers for smart irrigation advisories

Smart irrigation management is essential for improving crop resilience under increasing drought frequency driven by climate change. Although satellite-based remote sensing provides valuable tools for monitoring crop water status at large spatial scales, its accuracy is often limited in mountainous and heterogeneous agricultural landscapes. In this study, we investigated drought-induced metabolic responses in potato (Solanum tuberosum L.) to identify biochemical biomarkers that could complement satellite-based irrigation advisories in the mid-Himalayan region of India. A field experiment was conducted using a gradient of soil moisture regimes corresponding to moderate (50% field capacity), critical (25% field capacity), and extreme drought stress (5-8% field capacity). Satellite-derived evapotranspiration-based irrigation advisories were validated against in situ soil moisture measurements, revealing discrepancies attributed to the inability of satellite estimates to capture actual water loss under drought stress conditions, highlighting the need for additional ground-truth biomarkers across heterogeneous field conditions. To capture plant-level physiological responses, untargeted metabolite profiling of potato leaves was performed using gas chromatography-mass spectrometry (GC-MS). Approximately fifty metabolites belonging to amino acids, organic acids, sugars, and sugar alcohols were detected. Multivariate statistical analyses revealed distinct metabolic signatures associated with progressive drought stress. Notably, accumulation of proline, serine, isoleucine, sucrose, fructose, glucose, and polyols such as mannitol and myo-inositol reflected key metabolic reprogramming associated with osmoprotection, redox homeostasis, and energy metabolism under drought conditions. Collectively, this ensemble of stress-responsive metabolites represents a robust panel of drought stress biomarkers. As a proof of concept, proline was validated as a qualitative biomarker of plant water status through a rapid and cost-effective colorimetric biochemical assay, demonstrating its practical applicability for field-level irrigation management. These findings demonstrate that metabolomics-derived biomarkers can provide sensitive plant-level indicators of drought stress that complement satellite-based monitoring systems. The integration of biochemical diagnostics with remote sensing platforms offers a promising approach for improving drought detection and developing low-cost, field-deployable tools for smart irrigation advisories in heterogeneous agricultural landscapes. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=93 SRC="FIGDIR/small/712810v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@5b4c6dorg.highwire.dtl.DTLVardef@1f6af44org.highwire.dtl.DTLVardef@6cd9f7org.highwire.dtl.DTLVardef@5a0f5a_HPS_FORMAT_FIGEXP M_FIG C_FIG

plant biology↗