Biology subjects

Bhosale, R.

Publications and source records attributed to Bhosale, R..

6 recordsLinked to original sources

bioRxiv2026

Cytokinin regulates the gravitropic setpoint angle of seminal roots in barley and wheat

Plant root growth angle determines the spatial distribution of roots in soil and thereby influences access to water and nutrients when these resources are heterogeneously distributed. In barley, multiple seminal roots emerge at distinct gravitropic setpoint angles (GSAs) and they reliably re-establish their characteristic growth angles following reorientation, indicating robust intrinsic control. However, the molecular basis underlying GSA variation among roots within a single root system remains unknown. Here, we combined individual root type-specific transcriptomics with laser-capture microdissection to profile gravity-responsive zones (root cap, meristem, and elongation zone). We identified two CYTOKININ OXIDASE/DEHYDROGENASE (CKX) genes whose expression in the root cap was associated with root-specific GSA. Functional analysis showed that ckx mutants, which show higher cytokinin levels, exhibit significantly steeper seminal root GSAs, implicating cytokinin catabolism in root angle regulation. Consistent with this, exogenous cytokinin treatment induced a dose-dependent steepening in root angle in barley. Analyses of gravitropic curvature after gravistimulation further showed that ckx mutants exhibit altered gravitropic responses, indicating that CKX-mediated regulation of the root angle depends on gravity-responsive pathways. Notably, GSA-associated CKX expression patterns and cytokinin-dependent root angle responses were also observed in wheat, suggesting a conservation of this mechanism across cereals. Together, these findings identify cytokinin as a key regulator of root specific setpoint angles within a root system architecture, with potential implications for optimizing crop resource acquisition and yield.

plant biology↗

bioRxiv2025

Mutations in HOMEOBOX DOMAIN-2 improve grain protein content in wheat without significantly affecting grain yield and senescence

MicroRNA-resistant alleles of HOMEOBOX DOMAIN-2 (HB-2) were recently reported to improve grain protein content (GPC) in wheat by modifying vascular development in stems to increase amino acid distribution to grain. However, it is not known if these alleles increase GPC at the expense of other physiologically important traits, such as senescence and yield-component traits. Here, we evaluated the effects of mutations in HB-2 on grain yield and nitrogen (N)-use efficiency as well as senescence and plant architecture in multi-environment glasshouse and field experiments. In glasshouse experiments, the mutations in HB-2 moderately improved GPC irrespective of N supply and without accelerating senescence or decreasing grain number or weight compared to the wildtype spring wheat cv. Cadenza. The trait analysis indicated mutant plants were more tolerant of N limitation in terms of above-ground N reduction compared to the wild type. The expression of all HB-2 homeologues increased in spikes at the lemma primordium stage in response to N limitation, indicating the later GPC increase could be a result of enhanced N sink strength determined during early development, rather than processes caused by direct changes in HB-2 expression in the grain. In field experiments, the introgression of HB-2 alleles into Australian elite spring wheat cultivars significantly improved GPC without compromising grain yield. The outcomes of this study support the introduction of miRNA-resistant HB-2 alleles, with a preference to HB-A2, into commercial wheat for improving grain quality without a yield penalty.

plant biology↗

bioRxiv2025

Ubiquitin-like SUMO protease expansion in rice (Oryza sativa)

O_LISUMOylation is a protein post-translational modification that is essential for plant growth and response to changing environments. However, past work in this area has mainly focused on simple sequence similarity methods for discovering SUMOylation genes, often using orthologue mapping from yeast or Arabidopsis. C_LIO_LIIn this work, we employed a range of computational techniques and approaches to describe and characterise the SUMOylation machinery in Asian rice (Oryza sativa), as a globally important stable crop, and where the SUMOylation system has been shown to play key roles in responses to biotic and abiotic stresses. We describe and analyse the ULP system at the phylogenetic, transcriptional, and protein structural levels, with a focus on the rice reference genome, a well-annotated Rice Population Reference Panel (RPRP), and wild rice genomes. C_LIO_LIOur analysis revealed the expansion of ULPs in the reference genome and RPRP set (32 - 45 ULPs) compared to wild rice (9-36 ULPs), raising an intriguing hypothesis about the expansion of the ULP family being driven by selective breeding pressure. C_LIO_LIWe provide evidence of potential functional ULPs and their possible roles in biotic and abiotic stress responses in cultivated rice. These insights offer valuable resources for future rice breeding and crop improvement. C_LI

plant biology↗

bioRxiv2025

Elucidating tissue and sub-cellular specificity of the entire SUMO network reveals how stress responses are fine-tuned in a eukaryote

SUMOylation is essential in plant and animal cells, but it remains unknown how SUMO components act in concert to modify specific targets in response to environmental stresses. In this study we characterise every SUMO component in the Arabidopsis root to create the first complete SUMO Cell Atlas in eukaryotes. This unique resource reveals wide spatial variation, where SUMO proteins and proteases have sub-functionalized in both their expression and subcellular localisation. During stress SUMO conjugation is mainly driven by tissue specific regulation of the SUMO E2 ligase. Stress-specific modulation of the SUMO pathway reveals unique combinations of Proteases being targeted for regulation in distinct root tissues by salt, osmotic and biotic signals. Our SUMO Cell Atlas resources reveal how this PTM influences cellular and tissue scale adaptations during root development and stress responses. We provide the first comprehensive study elucidating how multiple stress inputs can regulate an entire PTM system.

plant biology↗

bioRxiv2024

Root metaxylem area influences drought tolerance and transpiration in pearl millet in a soil texture dependent manner

O_LIPearl millet is a key cereal for food security in drylands but its yield is strongly impacted by drought. We investigated how root anatomical traits contribute to mitigating the effects of vegetative drought stress in pearl millet. C_LIO_LIWe examined associations between root anatomical traits and agronomical performance in a pearl millet diversity panel under irrigated and vegetative drought stress treatments in field trials. The impact of associated anatomical traits on transpiration was assessed using subpanels grown in different soil within a greenhouse. C_LIO_LIIn the field, total metaxylem area was positively correlated with grain weight and its maintenance under drought. In the greenhouse, genotypes with larger metaxylem area grown in sandy soil exhibited a consumerist water use strategy under irrigation, which shifted to a conservative strategy under drought. Water savings was mediated by transpiration restriction under high evaporative demand. This mechanism was dependent on soil hydraulics as it was not observed in peat soil with higher hydraulic conductivity upon soil drying. C_LIO_LIWe propose that water savings under drought, mediated by large metaxylem area and its interaction with soil hydraulics, help mitigate vegetative drought stress. Our findings highlight the role of soil hydraulic properties in shaping plant hydraulics and drought tolerance. C_LI

physiology↗

bioRxiv2018

Vitamin D status and risk of incident tuberculosis disease: a systematic review and individual participant data meta-analysis

BackgroundFew studies have evaluated the association between pre-existing vitamin D deficiency (VDD) and incident TB. We assessed the impact of baseline vitamin D on TB risk. MethodsWe assessed the association between baseline vitamin D and incident TB in a prospective cohort of 6751 household contacts of TB patients in Peru. We also conducted a one-stage individual participant data meta-analysis searching PubMed and Embase for studies of vitamin D and TB until December 31, 2017. We included studies that assessed vitamin D before TB diagnosis. We defined VDD as 25-(OH)D <50 nmol/L, insufficiency as 50-75 nmol/L and sufficiency as >75nmol/L. We estimated the association between vitamin D and incident TB using conditional logistic regression in the Peru cohort and generalized linear mixed models in the meta-analysis. FindingsIn Peru, baseline VDD was associated with a statistically insignificant increase in incident TB (aOR 1{middle dot}70, 95% CI 0{middle dot}84-3{middle dot}46; p=0{middle dot}14). We identified seven studies for the meta-analysis and analyzed 3544 participants. Individuals with VDD and very low vitamin D (<25nmol/L) had increased TB risk (aOR 1{middle dot}48, 95% CI 1{middle dot}04-210;p=0{middle dot} 03 and aOR 2 08, 95% CI 0{middle dot}88-4{middle dot}92; p trend=002 respectively). Among HIV-positive patients, VDD and very low vitamin D conferred a 2-fold (aOR 2.18, 95% CI 1{middle dot} 22-3{middle dot}90; p=0{middle dot} 01) and 4-fold (aOR 4{middle dot}28, 95% CI 0{middle dot}85-21{middle dot}44; p trend=0{middle dot}01) increased risk of TB respectively. InterpretationOur findings suggest vitamin D predicts TB risk in a dose-dependent manner and vitamin D supplementation may play a role in TB prevention. FundingNational Institute of Health (NIH), National Institute of Allergy and Infectious Diseases (NIAID), National Institute on Drug Abuse (NIDA), National Institute of Mental Health (NIMH), International Maternal Pediatric Adolescent AIDS Clinical Trials Group (IMPAACT), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institute of Dental and Craniofacial Research (NIDCR), Boehringer-Ingelheim, Bristol-Myers Squibb, Gilead Sciences, GlaxoSmithKline, Foundation, Ujala Foundation, Wyncote Foundation, NIH - Fogarty International Center Program of International Training Grants in Epidemiology Related to AIDS, NIAID Byramjee Jeejeebhoy Medical College HIV Clinical Trials Unit, NIAIDs Baltimore-Washington-India Clinical Trials Unit, National Commission on Biotechnology, the Higher Education Commission, International Research Support Initiative Program of the Higher Education Commission Government of Pakistan, the Bill and Melinda Gates Foundation, and the NIH Fogarty International Center. Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSNumerous studies have found lower serum vitamin D levels among patients with active TB disease compared to healthy controls. However, research has not clarified whether low vitamin D increases TB risk or whether TB disease leads to decreased vitamin D levels. We conducted PubMed and Medline searches for all studies available through December 31, 2017 on the association between vitamin D status and TB disease. We included the following keywords: "vitamin D," "vitamin D deficiency," "hypovitaminosis D," "25-hydroxyvitamin D," "1,25-dihydroxyvitamin D," "vitamin D2," "vitamin D3," "ergocalciferol," "cholecalciferol," and "tuberculosis." We found only seven studies had prospectively evaluated the impact of baseline vitamin D levels on risk of progression to TB disease. We report here the results of a case control study nested within a large prospective longitudinal cohort study of household contacts of TB cases and the results of an individual participant data (IPD) metaanalysis of available evidence on the association between vitamin D levels and incident TB disease. Added value of this studyWe demonstrated that low vitamin D levels predicts risk of future progression to TB disease in a dose-dependent manner. Implications of all the available evidenceThese findings suggest the possibility that vitamin D supplementation among individuals at high risk for developing TB disease might play a role in TB prevention efforts.

epidemiology↗