Phosphorus-Induced Change in Root Hair Growth Is Associated with IAA Accumulation in Walnut

The study examined how phosphorus stress affected root hair growth in walnut seedlings, highlighting the role of auxin (IAA) biosynthesis and transport. Under low phosphorus conditions, root hair growth increased significantly, associated with the up-regulation of the JrCPC gene and down-regulation of the JrTTG1 gene, along with higher root IAA levels and IAAO activities. Conversely, no phosphorus conditions resulted in decreased root hair growth and reduced gene expression. The findings indicated that phosphorus influenced root hair growth by regulating auxin transport, impacting root nutrient absorption and plant growth, while the auxin biosynthesis gene CsYUCCA1 remained unaffected by phosphorus levels.