ABA plays essential roles in regulating root growth by interacting with auxin and MAPK signaling pathways and cell-cycle machinery in rice seedlings

Abstract

In this study, we examined the relationship between abscisic acid (ABA), auxin, and mitogen-activated protein kinase (MAPK) signaling and the cell cycle in rice (Oryza sativa L. cv. Zhonghua No. 11) roots. Root system growth was significantly promoted by 0.1 nM ABA but markedly inhibited by 0.3 mM Tungstate (TS, an ABA biosynthesis inhibitor). Detection of plants treated with DRB (an RNA synthesis inhibitor, 5,6-dichlorobenzimidazole 1-b-D-ribofuranoside), TIBA (2,3,5-triiodobenzoic acid, an inhibitor of polar auxin transport), or BFA (brefeldin, a protein transport inhibitor) using DR5-GUS staining revealed that ABA regulates the distribution of auxin via transcription and transport pathways. The expression of some auxin-and cell cycle-related genes, as well as several ABA or MAPK genes, was differentially regulated in roots by ABA and TS at 7 or 11 days, indicating that a certain level of ABA action may primarily target specific genes involved in MAPK and auxin signaling and the cell cycle at a given developmental stage. The results suggest that an appropriate level of ABA determines auxin homeostasis through controlling gene expression and the distribution of auxin, and that ABA regulates the auxin and MAPK signaling pathways and influences cell-cycle progression. Overall, ABA plays positive roles in regulating root system growth by modulating MAPK and auxin signaling and the cell cycle. Our findings help elucidate the integrative effects of ABA, auxin, and MAPK signaling and the cell cycle on root growth. We propose a working model for the role of ABA in root system growth.

The Biphasic Root Growth Response to Abscisic Acid in Arabidopsis Involves Interaction with Ethylene and Auxin Signalling Pathways

“…By contrast, both NPA and TIBA were successful in blocking the stimulatory effect of low [ABA] and the pin2/eir1-1 mutant (but not the other tested pin mutants) was also defective in its response to low [ABA] ( Figures 4 , 5A,B ). This evidence of the importance of auxin efflux in the response to low [ABA] agrees with a previous report that TIBA was able to partially suppress the positive effect of a low concentration of ABA on root growth in rice ( Zhao et al, 2015 ).…”

“…A role for auxin in the inhibitory effect of high [ABA] on Arabidopsis root growth has already been established from a number of studies using mutants defective in auxin transport and signalling ( Belin et al, 2009 ; Wang et al, 2011 ; Thole et al, 2014 ; Zhao et al, 2015 ). Additionally, the distribution of GFP in the root tip of the DR5::GFP auxin reporter line was altered by adding either low or high [ABA] compared with the control (Supplementary Figure 2 ), which is consistent with the idea that auxin is involved in regulating root growth responses to both low and high [ABA].…”

Retention, Molecular Evolution, and Expression Divergence of the Auxin/Indole Acetic Acid and Auxin Response Factor Gene Families inBrassica RapaShed Light on Their Evolution Patterns in Plants

“…Gene expression is not only usually tissue specific but is also hormone or stress induced. Additionally, parts of the growth and developmental processes were regulated by crosstalk between auxin and other hormones (ethylene and ABA) according to previous reports ( Muday et al 2012 ; Zhao et al 2015 ). Moreover, auxin was confirmed as a regulator of cold stress response ( Rahman 2013 ).…”

Comprehensive Transcriptomic Analysis of Auxin Responses in Submerged Rice Coleoptile Growth

“…The involvement of phytohormones in regulating rice coleoptile elongation under different environmental conditions is complicated, and hormones may contribute to forming an effector system for environmental factors for the control of coleoptile elongation in rice [5][6][7]. Ethylene promotes rice coleoptile elongation under submerged conditions.…”