Dynamic Changes in Tomato (<i>Solanum lycopersicum</i>) RNA m⁶A Modification During Seed Germination and Under Microgravity Conditions

Research exploring involvement of RNA <i>N</i>⁶-methyladenosine (m⁶A) in tomato (<i>Solanum lycopersicum</i>) seed germination remains limited. There is also a lack of direct evidence supporting the interaction among tomato seed germination, microgravity, and m⁶A modification. In this study, Micro-Tom tomatoes are used as the experimental material to conduct tomato genetic transformation, seed germination assay, and m⁶A modification levels identification experiments. During tomato seed germination processes, the m⁶A modification level significantly increases under the mutual influence of various m⁶A methyltransferase subunits and multiple eraser proteins. As a m⁶A reader gene, <i>SlYTP9</i> expression significantly affects the germination of tomato seeds, with promotion and inhibition in OE (overexpression) and RNAi (RNA interference) transgenic tomato plants, respectively. Microgravity promotes seed germination in the early germination period (0–3 days past germination; 0–3 DPG), but this promoting effect gradually disappears as the seedling grows (8–15 DPG). Further exploration revealed that this promoting effect is correlated with m⁶A modification, manifested as enhanced expression of most m⁶A writer genes; increased expression levels of overall reader genes; altered expression trends of some m⁶A eraser genes, particularly <i>SlALKBH2</i>; and enhanced m⁶A modification levels. The experimental results obtained in this study can provide a theoretical basis and evidence support for elucidating the role of m⁶A in tomato seed germination, as well as for exploring the interactions between seed germination, microgravity, and m⁶A modification.