| Title | The NtMYC2-NtABI5 module regulates abscisic acid mediated seed germination in tobacco |
| Author | Jing, Yifen |
| Publication | SEED BIOLOGY |
| Year | 2026 |
| Volume | 5 |
| Corresponding Author | Chen, LG |
| Abstract | In tobacco, the basic helix-loop-helix (bHLH) transcription factor MYC2 contributes significantly to the biosynthesis and transport of nicotine, and also participates in the regulation of pollen development. However, their biological functions in seed germination remain largely unknown. Here, we examined the regulatory roles of NtMYC2a and NtMYC2b in abscisic acid (ABA) mediated seed germination. The expression of both NtMYC2a and NtMYC2b was repressed by ABA at both mRNA and protein levels. Simultaneous knock out of NtMYC2a and NtMYC2b reduced ABA signaling to promote seed germination, while overexpression of NtMYC2a or NtMYC2b resulted in the germinated seeds being more ABA-sensitive. Gene expression analysis showed that the expression of both NtABI3 and NtABI5 was reduced in Ntmyc2a/2b double mutants, but enhanced in transgenic plants overexpressing NtMYC2a or NtMYC2b. Both electrophoretic mobility shift assays (EMSA) and transient dual-luciferase reporter assays, revealed that both NtMYC2a and NtMYC2b could bind to the promoter of NtABI5 to activate its expression. Furthermore, NtMYC2a and NtMYC2b could interact with each other to form a heterodimer and function synergistically to activate the expression of NtABI5. Thus, these results provide evidence that the NtMYC2-NtABI5 module may function as a novel component in ABA signaling to positively modulate ABA-mediated seed germination in tobacco. |
