Plant materials and GA treatment
Agrobacterium rhizogenes (ATCC15834 ) was used to infect the terile plantlets to obtain the S. miltiorrhiza hairy roots, as previously reported (Ru et al. , 2016). (0.3 g fresh weight hairy roots were cultured in the liquid 6,7-V medium and sub-cultured every 30 days. The 21-day-old hairy roots were treated with GA3 (100 μM final concentration) for 2 h, 24 h or 6 days. Control hairy roots were not treated without GA3. Three independent biological replicates were performed in all treatments.
The phloem tissue, xylem tissue and periderm tissue of the roots were collected from the 2-year-old S. miltiorrhiza to analyze the tissue-specific expressions of SmGRAS5 and the tanshinones accumulation.