Shuaiqi Yang, Nuo Xu, Nana Chen, Jiaxuan Qi, Abdul Salam, Junyu Wu, Yihua Liu, Linli Huang, Bohan Liu & Yinbo Gan

Theoretical and Applied Genetics volume 136, Article number: 108

Key message

Root hairs are required for water and nutrient acquisition in plants. Here, we report a novel mechanism that OsUGE1 is negatively controlled by OsGRF6 to regulate root hair elongation in rice.

Abstract

Root hairs are tubular outgrowths generated by the root epidermal cells. They effectively enlarge the soil-root contact area and play essential roles for nutrient and water absorption. Here, in this study, we demonstrated that the Oryza sativa UDP-glucose 4-epimerase 1-like (OsUGE1) negatively regulated root hair elongation and was directly targeted by Oryza sativa growth regulating factor 6 (OsGRF6). Knockout mutants of OsUGE1 using CRISPR-Cas9 technology showed longer root hairs than those of wild type. In contrast, overexpression lines of OsUGE1 displayed shorter root hair compared with those of wild type. GUS staining showed that it could specifically express in root hair. Subcellular localization analysis indicates that OsUGE1 is located in endoplasmic reticulum, nucleus and plasma membrane. More importantly, ChIP-qPCR, Yeast-one-hybrid and BiFC experiments revealed that OsGRF6 could bind to the promoter of OsUGE1. Furthermore, knockout mutants of OsGRF6 showed shorter root hair than those of wild type, and OsGRF6 dominantly expressed in root. In addition, the expression level of OsUGE1 is significantly downregulated in Osgrf6 mutant. Taken together, our study reveals a novel pathway that OsUGE1 is negatively controlled by OsGRF6 to regulate root hair elongation in rice.

See https://link.springer.com/article/10.1007/s00122-023-04356-4

Fig. 1 The secondary homorhizic rice root system. Several crown roots emerge postembryonically from shoot nodes. Crown roots bear large lateral roots and fine lateral roots. Fine lateral roots also form on large lateral roots. The micrographs show cross-sections of the respective root type and the absence of cortex tissue in fine lateral roots. Note the cortex cells adjacent to lateral root emergence on an aerenchymatic crown root (black arrows). ae, aerenchyma; CR, crown root; FLR, fine lateral root; LLR, large lateral root; bar, 50 µm. (Gutiahr et al. 2009)