Benzyladenine affects polyamine contents and proteomic profiles during in vitro shoot development and ex vitro rooting in Dalbergia nigra (Vell.) Allemao ex Benth. (Fabaceae)

Key message BA significantly affected shoot multiplication and rooting and induced changes in PAs and proteomic profiles during micropropagation of Dalbergia nigra. Dalbergia nigra is an endangered species from the Brazilian Atlantic Rainforest, and in vitro propagation can be applied for its conservation. The aim of this study was to establish in vitro propagation and ex vitro rooting in D. nigra and evaluate the alterations in polyamines (PAs) and protein profiles during shoot development. The effects of MS and WPM culture media on in vitro germination were tested. For shoot induction, explants of apical and cotyledonary nodal segments from 45 day-old seedlings were inoculated in WPM culture medium supplemented with benzyladenine (BA; 0, 2.5 and 5 mu M). Shoots obtained in vitro without and with 2.5 mu M BA were rooted ex vitro with different concentrations (0, 100 and 500 mu M) of indole-3-butyric acid (IBA). The seedlings grew best in WPM culture medium. Treatment with 2.5 mu M BA significantly increased the shoot length by increasing free putrescine contents and the accumulation of proteins associated with shoot elongation, such as aspartate aminotransferase, elongation factor, calreticulin-3, and cell division cycle protein 48. Ex vitro rooting was obtained in all treatments, and the use of auxin was not necessary. The BA used for shoot multiplication significantly affected rooting, reducing the induction and number of roots but increasing their length. This study showed the relevance of cytokinin, PAs and proteomic profiles to in vitro shoot development, as well as the auxin and cytokinin balance to ex vitro rooting in D. nigra.

Automated summary

This study investigated the in vitro propagation and ex vitro rooting of Dalbergia nigra and found that cytokinin, polyamines, and protein profiles play important roles in shoot development, while the balance between auxin and cytokinin affects ex vitro rooting.