Large Grain 2, an NHL Domain-Containing Protein, Interacts with FUWA and Regulates Plant Architecture and Grain Size Through the Brassinosteroid Signaling Pathway in Rice

Plant architecture and grain size are critical traits for rice breeding. Brassinosteroid (BR), a class of plant hormones, regulates these traits by modulating cell elongation, division, and differentiation. Therefore, exploring BR-related genes to leverage their pleiotropic effects is crucial for crop improvement. We identify a novel gene, Large Grain 2 (LG2), which encodes a Golgi-localized protein containing an NHL domain. This gene plays a crucial role in regulating both plant architecture and grain size in rice. Mechanistically, FUWA, a paralog of LG2, directly interacts with LG2 and enhances its protein stability. Furthermore, our findings indicate that LG2 is involved in BR signaling. Collectively, these results suggest that the LG2-FUWA module synergistically regulate plant architecture and grain size through the BR pathway in rice. Our study provides new insights into the function of NHL domain-containing proteins in plants and introduces a novel BR component for crop improvement. The LG2-FUWA module regulates plant architecture and grain size through the BR pathway in rice.