Abstract
Context Ratoon stunting disease (RSD), caused by Leifsonia xyli subsp. xyli (Lxx), poses a significant economic threat to sugarcane (Saccharum hybrid) worldwide. RSD is hard to manage due to its elusive visible symptomology and disease rating of cultivars is subjective. Aims We aimed to develop a sensitive, rapid, and quantitative Lxx diagnostic method able to correlate Lxx titre and disease resistance rating of sugarcane cultivars. Methods A Lxx diagnostic method was developed using heat lysis-based reagent-free DNA isolation from xylem sap followed by loop-mediated isothermal amplification (LAMP)-based colorimetric and fluorescence quantification within a single microcentrifuge tube. Bacterial titre was then statistically correlated with industry-agreed disease resistance ratings for key sugarcane cultivars. Key results The diagnostic was highly sensitive (1 cell/μL) and reproducible (%s.d. = <5%, for n = 3), and showed excellent linear dynamic range (i.e. 10 pM−1 aM or 107−100 copies/μL, r = 0.99) for quantitative Lxx detection. LAMP quantifications were completely concordant with quantitative polymerase chain reaction quantification from the same samples. Additionally, a strong correlation was determined between the detected quantitative bacterial titres and known cultivar disease resistance ratings (r = 0.82, n = 10, P < 0.001). Conclusion The novel LAMP-based Lxx diagnostic was validated as a fast, simple, and relatively cost-effective means of RSD resistance rating, making it a reliable contribution towards RSD management. Implications The development of this diagnostic tool provides a practical solution for accurately measuring Lxx titre and assessing disease resistance in sugarcane plants, aiding in effective risk management of RSD spread, and mitigating its economic impact on sugarcane crops worldwide.
Funder
Griffith University
Australian Research Council
Reference66 articles.
1. Bailey RA, Bechet GR (1997) Further evidence of the effects of ratoon stunting disease on production under irrigated and rainfed conditions. ln ‘Proceedings of South African Sugar Technology Association’. Vol. 1, pp. 97–101.
2. Benda GTA, Ricaud C (1978) The use of hot-water treatment for sugarcane disease control. In ‘Proceedings of the International Society of Sugar Cane Technologists’. Vol. 16, pp. 483–496.
3. Bhuiyan SA, Eglinton J, Magarey RC (2021) Prospects for a genetic solution to the management of ratoon stunting disease. ln ‘Proceedings of the Australian Society of Sugarcane Technologists’. Vol. 42, pp. 527–532.
4. Transformation and transposon mutagenesis of subsp. , causal organism of ratoon stunting disease of sugarcane.;Molecular Plant Microbe Interactions,2002
5. Development of a quantitative real-time PCR protocol for the analysis of early colonization of sugarcane plantlets with subsp. .;Phytopathology,2010