Genome-wide identification and characterization of Respiratory Burst Oxidase Homolog genes in six Rosaceae species and an analysis of their effects on adventitious rooting in apple

Abstract

Adventitious root formation is essential for plant propagation, development, and response to various stresses. Reactive oxygen species (ROS) are essential for adventitious root formation. However, information on Respiratory Burst Oxidase Homolog (RBOH), a key enzyme that catalyzes the production ROS, remains limited in woody plants. Here, a total of 44 RBOH genes were identified from six Rosaceae species (Malus domestica, Prunus avium, Prunus dulcis 'Texas', Rubus occidentalis, Fragaria vesca and Rosa chinensis), including ten from M. domestica. Their phylogenetic relationships, conserved motifs and gene structures were analyzed. Exogenous treatment with the RBOH protein inhibitor diphenyleneiodonium (DPI) completely inhibited adventitious root formation, whereas exogenous H 2 O 2 treatment enhanced adventitious root formation. In addition, we found that ROS accumulated during adventitious root primordium inducing process. The expression levels of MdRBOH-H, MdRBOH-J, MdRBOH-A, MdRBOH-E1 and MdRBOH-K increased more than twofold at days 3 or 9 after auxin treatment. In addition, cis-acting element analysis revealed that the MdRBOH-E1 promoter contained an auxin-responsive element and the MdRBOH-K promoter contained a meristem expression element. Based on the combined results from exogenous DPI and H 2 O 2 treatment, spatiotemporal expression profiling, and cis-element analysis, MdRBOH-E1 and MdRBOH-K appear to be candidates for the control of adventitious rooting in apple.

Genome Wide Identification of Respiratory Burst Oxidase Homolog (Rboh) Genes in Citrus sinensis and Functional Analysis of CsRbohD in Cold Tolerance

“…Prediction programs for subcellular localization showed that the seven CsRboh proteins were localized in the cell membrane. The results are in agreement with those obtained in other studies [ 10 , 13 , 14 , 16 , 28 ], suggesting Rbohs’ potential role in the regulation of ROS generation. Notably, few Rboh proteins were predicted to localize in chloroplast thylakoid membranes or mitochondria.…”

Integrated transgene and transcriptome reveal the molecular basis of MdWRKY87 positively regulate adventitious rooting in apple rootstock

“…To further define the relationship between MdWRKY87 expression levels and adventitious rooting formation, we next examined the expression pattern of MdWRKY87 during adventitious rooting formation of tissue culture plantlets in apple. According to the paraffin sections of stem bases of apple plantlets, we found that primordia with dome-shaped adventitious structures were clearly visible at 6~9 days after transplanting ( Figure 1E ) as our previous results ( Cheng et al., 2020 ). After 12 days of transplantation, adventitious roots began to appear.…”

“…The expression of MdWRKY87 is positively correlated with auxin-induced adventitious root formation. dome-shaped adventitious structures were clearly visible at 6~9 days after transplanting (Figure 1E) as previous results (Cheng et al, 2020).…”

“…Tissue-cultured ‘M9T337’ plantlets were sub-cultured in Murashige and Skoog (MS) medium containing 7.5 g L -1 agar and 30 g L -1 sugar (pH 5.8) with 0.5 mg L -1 IBA and 0.2 mg L -1 6-benzylaminopurine (6-BA) ( Cheng et al., 2020 ). After 30 days, stem cuttings were transferred into 1/2 medium containing rooting 7.5 g L -1 agar and 30 g L -1 sugar (pH 5.8) with 0.5 mg L -1 IBA and 0.1 mg L -1 1-naphthalene acetic acid (NAA) for rooting.…”

“…Paraffin sections of stem bases were prepared as previously described ( Xu et al., 2017 ; Cheng et al., 2020 ; Jin et al., 2022 ), with some modifications. The bases of ‘M9T337’ stem cuttings were collected at 6, 9, and 12 days after transplanting on 1/2 MS medium with 0.5 mg L-1 IBA and 0.1 mg L-1 NAA.…”