Transcriptome analysis reveals the impact of short-term biochar application on starch and sucrose metabolism in sweet potato tuberous roots

Biochar has been proven to be an effective method for enhancing sweet potato yield. However, limited research has been conducted on the molecular and physiological mechanisms underlying biochar's regulation of starch biosynthesis. This study aimed to investigate the transcriptome sequencing, which revealed the effects of short-term biochar application (STBA) on tuberous roots of sweet potato and the. We designed four STBA treatments: 0 t·hm⁻² (CK), 5 t·hm⁻² (X5t), 10 t·hm⁻²(X10t), and 20 t·hm⁻²(X20t), through a comprehensive analysis encompassing physiological data and RNA-seq analysis. The investigation included a comprehensive analysis integrating physiological measurements with RNA-seq data to elucidate the underlying mechanisms. The results showed that STBA enhanced the availability of nitrogen and potassium significantly, while also elevating the soil's pH levels. The 20 t·hm⁻² STBA substantially enhanced sweet potato yields by 72.21 %, and the starch content of all STBA was not significantly different with CK. STBA decreased the sucrose, starch, glucose, and fructose content of tuberous root by 3–12 %, 1–5 %, 5–8 %, and 5–16 %. DEGs analysis identified distinct gene regulation patterns following biochar treatments, with the 5–10 t·hm⁻² dosages predominantly down-regulating genes, including those in starch and sucrose metabolism pathways. WGCNA analysis uncovered 11 modules, highlighting biochar's influence on hormone signal transduction pathways, which was validated through qRT-PCR of five key genes. The study's findings light on the impact of STBA on the starch quality of sweet potatoes and inform biochar application strategies in agriculture.