NF‐YC15 transcription factor activates ethylene biosynthesis and improves cassava disease resistance

Summary The nuclear factor Y (NF‐Y) transcription factors play important roles in plant development and physiological responses. However, the relationship between NF‐Y, plant hormone and plant stress resistance in tropical crops remains unclear. In this study, we identified MeNF‐YC15 gene in the NF‐Y family that significantly responded to Xanthomonas axonopodis pv. manihotis (Xam) treatment. Using MeNF‐YC15‐silenced and ‐overexpressed cassava plants, we elucidated that MeNF‐YC15 positively regulated disease resistance to cassava bacterial blight (CBB). Notably, we illustrated MeNF‐YC15 downstream genes and revealed the direct genetic relationship between MeNF‐YC15 and 1‐aminocyclopropane‐1‐carboxylic acid (ACC) oxidase (MeACO1)‐ethylene module in disease resistance, as evidenced by the rescued disease susceptibility of MeNF‐YC15 silenced cassava plants with ethylene treatment or overexpressing MeACO1. In addition, the physical interaction between 2C‐type protein phosphatase 1 (MePP2C1) and MeNF‐YC15 inhibited the transcriptional activation of MeACO1 by MeNF‐YC15. In summary, MePP2C1‐MeNF‐YC15 interaction modulates ethylene biosynthesis and cassava disease resistance, providing gene network for cassava genetic improvement.