Graphene oxide and indole-3-acetic acid cotreatment regulates the root growth of Brassica napus L. via multiple phytohormone pathways

Abstract

Background: Studies have indicated that graphene oxide (GO) could regulated Brassica napus L. root growth via abscisic acid (ABA) and indole-3-acetic acid (IAA). To study the mechanism and interaction between GO and IAA further, B. napus L (Zhongshuang No. 9) seedlings were treated with GO and IAA accordance with a two factor completely randomized design. Results: GO and IAA cotreatment significantly regulated the root length, number of adventitious roots, and contents of IAA, cytokinin (CTK) and ABA. Treatment with 25 mg/L GO alone or IAA (> 0.5 mg/L) inhibited root development. IAA cotreatment enhanced the inhibitory role of GO, and the inhibition was strengthened with increased in IAA concentration. GO treatments caused oxidative stress in the plants. The ABA and CTK contents decreased; however, the IAA and gibberellin (GA) contents first increased but then decreased with increasing IAA concentration when IAA was combined with GO compared with GO alone. The 9-cis-epoxycarotenoid dioxygenase (NCED) transcript level strongly increased when the plants were treated with GO. However, the NCED transcript level and ABA concentration gradually decreased with increasing IAA concentration under GO and IAA cotreatment. GO treatments decreased the transcript abundance of steroid 5-alpha-reductase (DET2) and isochorismate synthase 1 (ICS), which are associated with brassinolide (BR) and salicylic acid (SA) biosynthesis, but increased the transcript abundance of brassinosteroid insensitive 1-associated receptor kinase 1 (BAK1), cam-binding protein 60-like G (CBP60) and calmodulin binding protein-like protein 1, which are associated with BR and SA biosynthesis. Last, GO treatment increased the transcript abundance of 1-aminocyclopropane-1-carboxylic acid synthase 2 (ACS2), which is associated with the ethylene (ETH) pathway.(Continued on next page) Conclusions: Treatment with 25 mg/L GO or IAA (> 0.5 mg/L) inhibited root development. However, IAA and GO cotreatment enhanced the inhibitory role of GO, and this inhibition was strengthened with increased IAA concentration. IAA is a key factor in the response of B. napus L to GO and the responses of B. napus to GO and IAA cotreatment involved in multiple pathways, including those involving ABA, IAA, GA, CTK, BR, SA. Specifically, GO and IAA cotreatment affected the GA content in the modulation of B. napus root growth.

Overdominance at the Gene Expression Level Plays a Critical Role in the Hybrid Root Growth of Brassica napus

“…Nguyen et al and Zubo et al [104,105] suggested that the B-ARR gene family members (B-ARR1, B-ARR10, and B-ARR12) play large fundamental roles in the regulation of physiological and transcriptional responses to CK. Eth biosynthesis disruption or signal transduction affects the development of roots, hypocotyls, and seeds [106,107]. The current results revealed the up-regulation of ERS2, EBF1/2, ERF1/2, and MAPK6 in the FO hybrid.…”

Graphene Oxide, a Novel Nanomaterial as Soil Water Retention Agent, Dramatically Enhances Drought Stress Tolerance in Soybean Plants

“…Drought tolerance and improvement of soybean drought tolerance have been promising topics for scientific research. Graphene oxide (GO), a novel nanomaterial as a soil water retention agent, plays a role in the growth and development of plants ( Shen et al, 2018 ; Xie et al, 2020 ). GO not only increased the drought tolerance of in Zea mays L. and Paeonia ostii ( Zhao et al, 2020 ; Lopes et al, 2021 ), but also enhanced the saline-alkali tolerance of Medicago sativa L. ( Chen et al, 2021 ).…”

Graphene Oxide-Assisted Promotion of Plant Growth and Stability

“…In addition, Ratajczak et al revealed that the GO conjugated with a supramolecular including adenosine-5 -triphosphate (ATP), FI-TC (fluorescein isothiocyanate), and survivin molecular beacon (SurMB) can be used as a carrier for gene delivery, and the GO usually interacted with the molecules through the hydrogen bonds' formation and π-π stacking interactions [31,32]. Xie et al, reported the GO-based gene transcript levels of Brassica napus L. (B. napus) [34]. The authors treated the GO with difference concentrations (e.g., 0, 5, 25 mg/L) on B. napus.…”