The histone deacetylase 1/GSK3/SHAGGY-like kinase 2/BRASSINAZOLE-RESISTANT 1 module controls lateral root formation in rice

Lateral roots (LRs) are a main component of the root system of rice (Oryza sativa) that increases root surface area, enabling efficient absorption of water and nutrients. However, the molecular mechanism regulating LR formation in rice remains largely unknown. Here, we report that histone deacetylase 1 (OsHDAC1) positively regulates LR formation in rice. Rice OsHDAC1 RNAi plants produced fewer LRs than wild-type plants, whereas plants overexpressing OsHDAC1 exhibited increased LR proliferation by promoting LR primordia formation. Brassinosteroid treatment increased the LR number, as did mutation of GSK3/SHAGGY-like kinase 2 (OsGSK2), whereas overexpression of OsGSK2 decreased the LR number. Importantly, OsHDAC1 could directly interact with and deacetylate OsGSK2, inhibiting its activity. OsGSK2 deacetylation attenuated the interaction between OsGSK2 and BRASSINAZOLE-RESISTANT 1 (OsBZR1), leading to accumulation of OsBZR1. The overexpression of OsBZR1 increased LR formation by regulating Auxin/IAA signaling genes. Taken together, the results indicate that OsHDAC1 regulates LR formation in rice by deactivating OsGSK2, thereby preventing degradation of OsBZR1, a positive regulator of LR primordia formation. Our findings suggest that OsHDAC1 is a breeding target in rice that can improve resource capture. Histone deacetylase 1 mediates brassinosteroid signaling components to control rice lateral root formation, which elucidates a regulatory mechanism for molecular design breeding.

Automated summary

Lateral roots (LRs) are an important part of the root system in rice, which helps increase root surface area for efficient water and nutrient absorption. This study reveals that histone deacetylase 1 (OsHDAC1) plays a positive regulatory role in LR formation in rice. OsHDAC1 controls LR formation by deactivating OsGSK2 and preventing degradation of OsBZR1, which is a positive regulator of LR primordia formation. This finding provides insights into the molecular mechanism of LR formation in rice.