We studied the link between abscisic acid (ABA), auxin, MAPK (mitogen-activated protein kinase) signaling, and the cell cycle in cadmium (Cd)-stressed rice (Oryza sativa L. cv. Zhonghua No. 11) roots. ABA can partially compensate for root growth inhibition and counteract over-accumulation of auxin caused by Cd. GUS staining of rice plants harboring DR5-GUS showed that ABA affects auxin distribution in Cd-stressed roots. Detection using DRB (5,6-dichlorobenzimidazole 1-β-ᴅ-ribofuranoside, an RNA synthesis inhibitor), MG132 (a protein degradation inhibitor), BFA (brefeldin A, a protein transport inhibitor), and TIBA (2,3,5-triiodobenzoic acid, a polar auxin transport inhibitor) revealed that ABA regulates the distribution of auxin via transcription, protein degradation, and transport pathways under Cd stress. Several genes related to ABA and MAPK, key components of the auxin signaling pathway, and the cell cycle were differentially regulated by Cd plus ABA vs. Cd plus tungstate (TS) (a ABA biosynthesis inhibitor) at 7 days or 11 days of treatment in roots, indicating that ABA levels affect the transcription of these genes, and that these genes are differentially regulated by ABA in rice seedlings at different developmental stages. Furthermore, the expression of some of these genes differed between Cd + ABA/TS-treated plants and plants treated with TS or ABA alone, suggesting that ABA signaling serves specific functions in the regulation of gene expression under Cd stress. Overall, these results suggest that ABA coordinates auxin and MAPK signaling and the cell cycle in response to Cd stress. The ABA signal transduction pathways in Cd-stressed rice plants are discussed.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.