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Sparks, C.

Publications and source records attributed to Sparks, C..

2 recordsLinked to original sources
bioRxiv2023

CYTOCHROME P450 CYP72A219 IS INVOLVED IN EVOLUTION OF METABOLIC RESISTANCE TO TEMBOTRIONE IN Amaranthus palmeri POPULATIONS

Evolution of metabolic herbicide resistance is a major issue for weed management. Few genes and regulatory mechanisms have been identified, particularly in dicotyledonous weed species. We identified putative causal genes and regulatory mechanism for tembotrione-resistance in Amaranthus palmeri. Cytochrome P450 candidate genes were identified through RNA-seq analysis. We validated their functions using heterologous expression in S. cerevisae. Promoters of the candidate P450 genes were analyzed. We performed QTL mapping to identify genomic regions associated with resistance. CYP72A1182 deactivated tembotrione. This gene had increased expression in other A. palmeri populations resistant to multiple herbicides, including tembotrione. Resistant plants exhibited polymorphisms in the promoter of CYP72A1182. We identified QTLs linked to herbicide resistance, including one on chromosome 4 approximately 3 Mb away from CYP72A1182. CYP72A1182 is involved in tembotrione resistance in A. palmeri. Increased expression of this gene could be due to cis-regulation in the promoter, as well as trans-regulation from transcription factors. Further studies are in progress to test this hypothesis. The elucidation of regulatory genes is crucial for developing innovative weed management approaches and target-based novel molecules. HIGHLIGHTSOur study identifies that the CYP72A1182 gene has a functional role in metabolic herbicide resistance in Amaranthus palmeri and is linked to cis-regulatory polymorphisms, advancing metabolic resistance understanding in dicots.

plant biology↗
bioRxiv2017

Characterisation of an antimicrobial and phytotoxic ribonuclease secreted by the fungal wheat pathogen Zymoseptoria tritici

- The fungus Zymoseptoria tritici is the causal agent of Septoria Tritici Blotch (STB) disease of wheat leaves. Z. tritici secretes many functionally uncharacterised effector proteins during infection. Here we characterised a secreted ribonuclease (Zt6) with an unusual biphasic expression pattern.\n- Transient expression systems were used to characterise Zt6, and mutants thereof, in both host and non-host plants. Cell-free protein expression systems monitored impact of Zt6 protein on functional ribosomes, and in vitro assays of cells treated with recombinant Zt6 determined toxicity against bacteria, yeasts and filamentous fungi.\n- We demonstrated that Zt6 is a functional ribonuclease and that phytotoxicity is dependent on both the presence of a 22-amino acid N-terminal \"loop\" region and its catalytic activity. Zt6 selectively cleaves both plant and animal rRNA species, and is toxic to wheat, tobacco, bacterial and yeast cells but not to Z. tritici itself.\n- Zt6 is the first Z. tritici effector demonstrated to have a likely dual functionality. The expression pattern of Zt6 and potent toxicity towards microorganisms suggests that whilst it may contribute to the execution of wheat cell death, it is also likely to have an important secondary function in antimicrobial competition and niche protection.

plant biology↗