Biology subjects

Shivnauth, V.

Publications and source records attributed to Shivnauth, V..

3 recordsLinked to original sources

bioRxiv2023

Warm temperature suppresses plant systemic acquired resistance by intercepting the N-hydroxypipecolic acid immune pathway

Climate warming influences disease development by targeting critical components of the plant immune system, including pattern-triggered immunity (PTI), effector-triggered immunity (ETI) and production of the central defence hormone salicylic acid (SA) at the primary pathogen infection site. However, it is not clear if and/or how temperature impacts systemic immunity. Here we show that pathogen-triggered systemic acquired resistance (SAR) in Arabidopsis thaliana is suppressed at elevated temperature. This was accompanied by global downregulation of SAR-induced genes at elevated temperature. Abolished SAR under warmer conditions was associated with reduced biosynthesis of the SAR metabolite N-hydroxypipecolic acid (NHP) in Arabidopsis and other plant species (such as tomato and rapeseed), as demonstrated by downregulation of NHP biosynthetic genes (ALD1 and FMO1) and reduced NHP and pipecolic acid (Pip) levels. Although multiple SAR signals have been shown previously, exogenous NHP or Pip was sufficient to restore disease protection at elevated temperature, indicating that heat-mediated SAR suppression is due to downregulation of the NHP pathway. Along with ALD1 and FMO1, local and systemic expression of the SA biosynthetic gene ICS1 were also suppressed at warm temperature. Finally, we define a transcriptional network controlling thermosensitive NHP pathway via the master transcription factors CBP60g and SARD1. Our findings demonstrate that warm temperatures impact not only local but also systemic immunity by impinging on NHP biosynthesis, providing a roadmap towards engineering climate-resilient plant immune systems.

plant biology↗

bioRxiv2022

Structural diversity and stress regulation of the plant immunity-associated CALMODULIN-BINDING PROTEIN 60 (CBP60) family of transcription factors in Solanum lycopersicum (tomato)

Cellular signalling generates calcium (Ca2+) ions, which are ubiquitous secondary messengers decoded by calcium-dependent protein kinases, calcineurins, calreticulin, calmodulins (CAMs) and CAM-binding proteins. Previous studies in the model plant Arabidopsis thaliana have shown the critical roles of the CAM-BINDING PROTEIN 60 (CBP60) protein family in plant growth, stress responses and immunity. Certain CBP60 factors can regulate plant immune responses, like pattern-triggered immunity, effector-triggered immunity, and synthesis of major plant immune-activating metabolites salicylic acid (SA) and N-hydroxypipecolic acid (NHP). Although homologous CBP60 sequences have been identified in the plant kingdom, their function and regulation in most species remain unclear. In this paper, we specifically characterized 11 members of the CBP60 family in the agriculturally important crop tomato (Solanum lycopersicum). Protein sequence analyses revealed that three CBP60 homologs have the closest amino acid identity to Arabidopsis CBP60g and SARD1, master transcription factors involved in plant immunity. Strikingly, AlphaFold deep learning-assisted prediction of protein structures highlighted close structural similarity between these tomato and Arabidopsis CBP60 homologs. Conserved domain analyses revealed that they possess CAM-binding domains and DNA-binding domains, reflecting their potential involvement in linking Ca2+ signalling and transcriptional regulation in tomato plants. In terms of their gene expression profiles under biotic (Pseudomonas syringae pv. tomato DC3000 pathogen infection) and/or abiotic stress (warming temperatures), five tomato CBP60 genes were pathogen-responsive and temperature-sensitive, reminiscent of Arabidopsis CBP60g and SARD1. Overall, we present a genome-wide identification of the CBP60 gene/protein family in tomato plants, and we provide evidence on their regulation and potential function as Ca2+-sensing transcriptional regulators.

plant biology↗

bioRxiv2022

CBP60-DB: An AlphaFold-predicted plant kingdom-wide database of the CALMODULIN-BINDING PROTEIN 60 (CBP60) protein family with a novel structural clustering algorithm

Molecular genetic analyses in the model species Arabidopsis thaliana have demonstrated the major roles of different CAM-BINDING PROTEIN 60 (CBP60) proteins in growth, stress signaling, and immune responses. Prominently, CBP60g and SARD1 are paralogous CBP60 transcription factors that regulate numerous components of the immune system, such as cell surface and intracellular immune receptors, MAP kinases, WRKY transcription factors, and biosynthetic enzymes for immunity-activating metabolites salicylic acid (SA) and N-hydroxypipecolic acid (NHP). However, their function, regulation and diversification in most species remain unclear. Here we have created CBP60-DB, a structural and bioinformatic database that comprehensively characterized 1052 CBP60 gene homologs (encoding 2376 unique transcripts and 1996 unique proteins) across 62 phylogenetically diverse genomes in the plant kingdom. We have employed deep learning-predicted structural analyses using AlphaFold2 and then generated dedicated web pages for all plant CBP60 proteins. Importantly, we have generated a novel clustering visualization algorithm to interrogate kingdom-wide structural similarities for more efficient inference of conserved functions across various plant taxa. Because well-characterized CBP60 proteins in Arabidopsis are known to be transcription factors with putative calmodulin-binding domains, we have integrated external bioinformatic resources to analyze protein domains and motifs. Collectively, we present a plant kingdom-wide identification of this important protein family in a user-friendly AlphaFold-anchored database, representing a novel and significant resource for the broader plant biology community.

bioinformatics↗