Polyploidized rice improves plant height and yield through regulation of the expression of yield-related genes

Polyploidization is one of the most effective ways to improve plant height and yield in rice ( Oryza sativa L.). However, the molecular mechanism of its regulation is not yet fully understood. Here, we investigated the agronomic traits of diploid ('Balilla2x') and tetraploid ('Balilla-4x') lines of the japonica rice variety 'Balilla'. Compared with 'Balilla-2x', 'Balilla-4x' exhibited significantly increased plant height, spike length and yield per plant. RNA-seq analysis showed that the expression levels of yield-related genes controlling plant height and panicle development (e.g., STH1 , OsYUC9 and OsDEP1 ) were significantly upregulated in 'Balilla-4x' rice plants. These results indicated that polyploidization changed the expression of genes related to agronomic traits such as plant height and spike length, thereby increasing rice yield. This study provides a further basis for understanding the yield of rice after polyploidization and can serve as a new theoretical reference for breeding high-yielding rice varieties.