SPL14/17 act downstream of strigolactone signalling to modulate rice root elongation in response to nitrate supply

Nitrogen (N) is an essential major nutrient for food crops. Although ammonium (NH4+) the primary N source of rice (Oryza sativa), nitrate (NO3?) can also be absorbed and utilized. Rice responds to NO3? application by altering its root morphology, such as elongation. Strigolactones (SLs) are important modulators length. However, roles SLs their downstream genes in NO3?-induced elongation remain unclear. Here, levels total SL (4-deoxyorobanchol) responses seminal (SR) lengths NH4+ were investigated plants. promoted SR elongation, possibly due short-term signal perception long-term function. Compared with conditions, higher signalling/levels less D53 protein recorded roots NO3?-treated In contrast wild-type plants, d mutants responsive rac-GR24 (SL analogue) restored length d10 biosynthesis mutant) but not d3, d14, d53 (SL-responsive mutants), suggesting that participate interacted SPL17 inhibited SPL17-mediated transactivation from PIN1b promoter. Mutation SPL14/17 caused insensitivity response applications. Therefore, we conclude D14 leads degradation via proteasome system, which releases suppression SPL14/17-modulated transcription PIN1b, resulting under supply.