Functional Analysis of PsARRO−1 in Root Development of Paeonia suffruticosa

Abstract

The adventitious rooting−related oxygenase (ARRO−1) gene is specifically expressed in the early rooting stage and is considered a molecular marker of rooting. In this study, a PsARRO−1 gene (GenBank accession number KJ620008) was identified from a pre−constructed transcriptome database of root development of Paeonia suffruticosa under sandy loam cultivation. The expression was verified by RT−qPCR, and it was found that the expression trend was consistent with the expression in the transcriptome database. The PsARRO−1 gene was specifically highly expressed during the root primordium germination phase. In addition, the RT−qPCR analysis indicated that the expression of PsARRO−1 in roots was significantly higher than in stems and leaves, its peak expression in vitro was 5 days earlier than in soil, and its expression was higher than that of tree peony in soil. Subcellular localization analysis showed that PsARRO−1 was localized in the plasma membrane. Moreover, the transient silent expression of the PsARRO−1 gene was found in the roots of peony seedlings grown using VIGS technology. The root activity was significantly reduced after transient silencing of the expression of the PsARRO−1 gene. These results indicate that PsARRO−1 has a positive regulatory effect on tree peony root development.

RNA Sequencing Analysis and Verification of Paeonia ostii ‘Fengdan’ CuZn Superoxide Dismutase (PoSOD) Genes in Root Development

“…Previous studies have reported that antioxidant enzymes may help maintain a stable level by regulating auxin oxidase, but the molecular mechanism remains unknown. Our results show that the overexpression of PoSOD increases the expression levels of PoARRO-1, which is specifically expressed during adventitious root development, and has a positive regulatory effect on root development in tree peony [29,30]. AtDAO1 and AtDAO2, which are homologous to ARRO-1, regulate the oxidation and homeostasis of IAA [44][45][46].…”

“…Materials for RNA-seq were obtained from P. ostii 'Fengdan' grown in the field at Henan Agricultural University in Zhengzhou, China. Based on morphological and anatomical observations by Sun et al [30], four crucial stages of adventitious root development were identified. During the root growth period of P. ostii 'Fengdan' from March to April, four stages were observed (Figure S9).…”

“…PoARRO-1 was cloned in P. ostii 'Fengdan' (GenBank: AIB53819.1), and its specific expression during adventitious root development was identified. It has a positive regulatory effect on root development via a mediating hormone [29,30]. Wang et al [31] also found that SOD activity played an important role in the root development of tree peony.…”

Establishment of a Homologous Silencing System with Intact-Plant Infiltration and Minimized Operation for Studying Gene Function in Herbaceous Peonies

“…Tree peonies are a group of woody species in the family Paeoniaceae, and they and herbaceous peonies are generally collectively referred to as "peonies". The silencing of flavonoid glycosyltransferase genes (UFGTs) and rooting-related oxygenase (ARRO-1) by VIGS in a tree peony, i.e., P. suffruticosa (a species of tree peonies), showed that the two genes play key roles in flower color formation and root development [21,22]. The TRYPTOPHAN DECARBOXYLASE gene (TDC) and WRKY41a are highly expressed in stems of P. lactiflora, and their silencing by VIGS decreases the secondary wall thickness and distinctly weakens the stem strength.…”