Genomics of Root System Architecture Adaptation in Sorghum under Nitrogen and Phosphorus Deficiency
Abstract
Plant root systems play a crucial role in water and nutrient uptake, yet the genetic mechanisms underlying root architecture adaptation to environmental stress remain poorly understood, particularly in non-model crops. Here, we investigate the diversity of root system architecture (RSA) inSorghum bicolor, a climate-resilient cereal, under nitrogen (N) and phosphorus (P) starvation. We used a diverse sorghum reference set, and employed crown root imaging technology to quantify RSA traits and performed a genome-wide association study (GWAS) to identify genetic factors driving these responses. Our analysis revealed significant changes in six RSA traits—average root diameter, surface area, volume, total root length, and root length diameter classes (RLDR1 and RLDR2)—under N and P starvation. GWAS identified SNPs associated with these traits, pinpointing three candidate genes—ILR3-like, bHLH, and aLEUNIGhomolog—with known roles in root growth regulation. These findings provide novel genetic insights into sorghum root adaptation to nutrient limitations and offer potential targets for breeding climate-resilient, resource-efficient crop varieties.
Summary
Plants absorb water and nutrients from the soil through their roots, yet for most crops, little is known about how root shape and structure adapt to stressful conditions such as poor soil fertility. In this study, we used a globally diverse collection of sorghum genotypes to investigate how sorghum roots respond to nitrogen and phosphorus deficiency. Remarkably, some genotypes showed strong root adaptations under these conditions, leading us to identify the genetic factors driving these responses. Our findings not only improve our understanding of root adaptation to nutrient stress but also highlight promising genetic targets for breeding more nutrient-efficient crops.
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