# A model-guided alternating high-temperature thermotherapy achieves complete eradication of sugarcane mosaic virus and preserves physiological integrity in Saccharum officinarum cv. Xuezhe

## TL;DR

A new heat treatment method effectively removes a virus from sugarcane without harming the plant, using a model to guide the process.

## Contribution

A model-guided alternating high-temperature thermotherapy protocol that effectively eradicates SCMV while preserving plant health.

## Key findings

- The optimized AHTT protocol achieved complete SCMV eradication with 97% sprouting and acceptable vigor.
- The protocol increased catalase activity and reduced peroxidase activity in treated plants.
- AHTT outperforms constant-temperature thermotherapy in virus elimination and plant preservation.

## Abstract

Sugarcane mosaic virus (SCMV) undermines both yield and eating quality of the chewing-cane cultivar Saccharum officinarum cv. Xuezhe. Although constant high-temperature thermotherapy can eliminate SCMV, it frequently causes serious heat injury in heat-sensitive genotypes. This study developed an alternating high-temperature thermotherapy (AHTT) scheme to eradicate SCMV while maintaining axillary-bud vigor on rooted cuttings.

A uniform-design experiment combined with quadratic regression analysis was used to optimize three factors: maximum treatment temperature (42–48 °C), duration of the high-temperature pulse (2–6 h in darkness), and the subsequent recovery phase at 38 °C (3–6 h under light). These cycles were applied daily over a 12-day regimen. Outcomes included sprouting, rooted-cutting performance, and virus elimination.

The model predicted an optimal schedule of 47 °C for 5 h (dark) followed by a 7-h recovery at 38 °C, repeated daily for 12 days; this schedule was experimentally validated. Under the optimized regime, axillary buds on 12-day-rooted cuttings were completely SCMV-free by RT-PCR, with 97% sprouting and acceptable vigor. AHTT was also associated with increased catalase (CAT) activity and reduced peroxidase (POD) activity.

The model-guided AHTT protocol reconciles effective SCMV eradication with acceptable plant stress and performs better than constant-temperature thermotherapy. It provides a practical, scalable, and environmentally friendly approach to generate virus-free sugarcane planting material, with potential relevance to other vegetatively propagated, heat-sensitive crops.