The study applied single-nucleus RNA sequencing to mature Sorghum bicolor leaves under well‑watered and drought conditions, identifying major leaf cell types and their transcriptional responses. Drought induced transcriptomic changes that surpassed cell‑type differences, indicating a common response across mesophyll, bundle sheath, epidermal, vascular, and stomatal cells, and enabling the identification of candidate drought‑responsive regulators for improving water‑use efficiency.

The study evaluated natural genetic variation in non-photochemical quenching and photoprotection across 861 sorghum accessions grown in the field over two years, revealing moderate to high broad-sense heritability for chlorophyll fluorescence traits. By integrating genome-wide association studies (GWAS) with transcriptome-wide association studies (TWAS) and covariance analyses, the authors identified 110 high-confidence candidate genes underlying photoprotection, highlighting a complex, polygenic architecture for these traits.

The study shows that drought triggers ABA accumulation and JA reduction in sorghum roots, accompanied by transcriptional activation of genes linked to mineral homeostasis, hormone signaling, and osmotic regulation, while Fe supplementation enhances ferritin expression and mitigates oxidative stress. Drought also diminishes root bacterial diversity but enriches beneficial taxa such as Burkholderia, whereas fungal diversity remains stable, and functional profiling reveals shifts toward phototrophy, methylotrophy, and nitrate reduction. These findings highlight ferritin’s protective role and suggest specific bacterial inoculants for improving sorghum drought resilience.