Overdominant expression of related genes of ion homeostasis improves K(+) content advantage in hybrid tobacco leaves

BACKGROUND: Potassium(K(+)) plays a vital role in improving the quality of tobacco leaves. However, how to improve the potassium content of tobacco leaves has always been a difficult problem in tobacco planting. K(+) content in tobacco hybrid is characterized by heterosis, which can improve the quality of tobacco leaves, but its underlying molecular genetic mechanisms remain unclear. RESULTS: Through a two-year field experiment, G70×GDH11 with strong heterosis and K326×GDH11 with weak heterosis were screened out. Transcriptome analyses revealed that 80.89% and 57.28% of the differentially expressed genes (DEGs) in the strong and weak heterosis combinations exhibited an overdominant expression pattern, respectively. The genes that up-regulated the overdominant expression in the strong heterosis hybrids were significantly enriched in the ion homeostasis. Genes involved in K(+) transport (KAT1/2, GORK, AKT2, and KEA3), activity regulation complex (CBL-CIPK5/6), and vacuole (TPKs) genes were overdominant expressed in strong heterosis hybrids, which contributed to K(+) homeostasis and heterosis in tobacco leaves. CONCLUSIONS: K(+) homeostasis and accumulation in tobacco hybrids were collectively improved. The overdominant expression of K(+) transport and homeostasis-related genes conducted a crucial role in the heterosis of K(+) content in tobacco leaves. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12870-022-03719-1.