Long-term subculture affects rooting competence via changes in the hormones and protein profiles in Cedrela fissilis Vell. (Meliaceae) shoots

Abstract

Long-term subculture plays an essential role in the large-scale multiplication and production of somatic plantlets. We investigated the effects of long-term subculture on in vitro shoot development and ex vitro rooting associated with changes in the hormones and protein pro les in C. ssilis. The number of subcultures of shoots induced a decrease in the ex vitro rooting response. The reduction in adventitious root (AR) formation was associated with decreases in the contents of indole-3-acetic acid (IAA), abscisic acid (ABA), 12-oxo phytodienoic acid (OPDA), putrescine (Put), and spermine and increases in jasmonic acid (JA), jasmonoyl-isoleucine, trans-cinnamic acid, and salicylic acid contents in shoots at the fourth subculture compared to the rst. The ornithine decarboxylase enzyme preferentially functions in the Put biosynthesis pathway and was related to the highest AR formation in shoots at the rst subculture. Down-accumulation of the auxin-binding protein ABP19a in shoots from the fourth subculture compared to the rst subculture was related to a decrease in both IAA contents and AR formation. In addition, downaccumulation of glucose-6-phosphate isomerase, glutamine synthetase leaf isozyme chloroplastic, 5methyltetrahydropteroyltriglutamate-homocysteine methyltransferase, L-ascorbate peroxidase, cytosolic, monodehydroascorbate reductase, and 2-Cys peroxiredoxin BAS1-like, chloroplastic and up-accumulation of caffeoyl-CoA O-methyltransferase 1 and isoforms of peroxidase 4 proteins in shoots from the fourth relative to the rst subculture were associated with a reduction in AR formation. These results showed that the understanding of hormonal and molecular mechanisms related to the potential of AR formation in shoots under successive subcultures is relevant to improving large-scale plantlet production in C. ssilis. Key MessageLong-term subculture affects the competence to ex vitro rooting of Cedrela ssilis shoots by changes in endogenous hormones and protein pro les.