LEAF TIP RUMPLED 1 Regulates Leaf Morphology and Salt Tolerance in Rice

Leaf morphology is one of the important traits related to ideal plant architecture and is an important factor determining rice stress resistance, which directly affects yield. Wax layers form a barrier to protect plants from different environmental stresses. However, the regulatory effect of wax synthesis genes on leaf morphology and salt tolerance is not well-understood. In this study, we identified a rice mutant, ( ), in a mutant library of the classic variety Nipponbare. Phenotypic investigation of NPB and suggested that showed rumpled leaf with uneven distribution of bulliform cells and sclerenchyma cells, and disordered vascular bundles. A decrease in seed-setting rate in led to decreased per-plant grain yield. Moreover, was sensitive to salt stress, and was strongly induced by salt stress. Map-based cloning of showed that there was a 2-bp deletion in the eighth exon of in , resulting in a frameshift mutation and early termination of transcription. Subsequently, the candidate gene was confirmed using complementation, overexpression, and knockout analysis of . Functional analysis of showed that it was a wax synthesis gene and constitutively expressed in entire tissues with higher relative expression level in leaves and panicles. Moreover, overexpression of enhanced yield in rice and positively regulates salt stress by affecting water and ion homeostasis. These results lay a theoretical foundation for exploring the molecular mechanism of leaf morphogenesis and stress response, providing a new potential strategy for stress-tolerance breeding.