Benzoxazinoids (BXs) are tryptophan-derived indole metabolites and play a role in various physiological processes, such as auxin metabolism. Auxin is essential in the process of somatic embryogenesis (SE) in plants. In this study, we used bioinformatics, transcriptome data, exogenous treatment experiments, and qPCR
[...] Read more.
Benzoxazinoids (BXs) are tryptophan-derived indole metabolites and play a role in various physiological processes, such as auxin metabolism. Auxin is essential in the process of somatic embryogenesis (SE) in plants. In this study, we used bioinformatics, transcriptome data, exogenous treatment experiments, and qPCR analysis to study the evolutionary pattern of
Bx genes in green plants, the regulatory mechanism of
DlBx genes during early SE, and the effect of 2,4-dihydroxy-7-methoxy-1,4-benzoxazine-3-one (DIMBOA) on the early SE in
Dimocarpus longan Lour. The results showed that 27 putative
DlBxs were identified in the longan genome; the
Bx genes evolved independently in monocots and dicots, and the main way of gene duplication for the
DlBx was tandem duplication (TD) and the
DlBx were strongly constrained by purification selection during evolution. The transcriptome data indicated varying expression levels of
DlBx during longan early SE, and most
DlBxs responded to light, temperature, drought stress, and 2,4-dichlorophenoxyacetic acid (2,4-D) treatment; qRT-PCR results showed
DlBx1,
DlBx6g and
DlBx6h were responsive to auxin, and treatment with 0.1mg/L DIMBOA for 9 days significantly upregulated the expression levels of
DlBx1,
DlBx3g,
DlBx6c,
DlBx6f,
DlB6h,
DlBx7d,
DlBx8, and
DlBx9b. The correlation analysis showed a significantly negative correlation between the expression level of
DlBx1 and the endogenous IAA contents; DIMBOA significantly promoted the early SE and significantly changed the endogenous IAA content, and the IAA content increased significantly at the 9th day and decreased significantly at the 13th day. Therefore, the results suggested that DIMBOA indirectly promote the early SE by changing the endogenous IAA content via affecting the expression level of
DlBx1 and hydrogen peroxide (H
2O
2) content in longan.
Full article