In Silico Genome-Wide Analysis of Respiratory Burst Oxidase Homolog (RBOH) Family Genes in Five Fruit-Producing Trees, and Potential Functional Analysis on Lignification of Stone Cells in Chinese White Pear

Abstract

The accumulation of lignin in fruit has a significant negative impact on the quality of fruit-producing trees, and in particular the lignin formation stimulates the development of stone cells in pear fruit. Reactive oxygen species (ROS) are essential for lignin polymerization. However, knowledge of the RBOH family, a key enzyme in ROS metabolism, remains unknown in most fruit trees. In this study, a total of 40 RBOHs were identified from five fruit-producing trees (Pyrus bretschneideri, Prunus persica, Citrus sinensis, Vitis vinifera, and Prunus mume), and 10 of these sequences came from Pyrus bretschneideri. Multiple sequence alignments revealed that all 10 PbRBOHs contained the NADPH_Ox domain and the six alpha-helical transmembrane domains (TM-I to TM-VI). Chromosome localization and interspecies phylogenetic tree analysis showed that 10 PbRBOHs irregularly distributed on 8 chromosomes and 3 PbRBOHs (PbRBOHA, PbRBOHB, and PbRBOHD) are closely related to known lignification-related RBOHs. Furthermore, hormone response pattern analysis showed that the transcription of PbRBOHs is regulated by SA, ABA and MeJA. Reverse transcription-quantitative real-time polymerase chain reaction (qRT-PCR) and transcriptome sequencing analysis showed that PbRBOHA, PbRBOHB, and PbRBOHD accumulated high transcript abundance in pear fruit, and the transcriptional trends of PbRBOHA and PbRBOHD was consistent with the change of stone cell content during fruit development. In addition, subcellular localization revealed that PbRBOHA and PbRBOHD are distributed on the plasma membrane. Combining the changes of apoplastic superoxide (O2.−) content and spatio-temporal expression analysis, these results indicate that PbRBOHA and PbRBOHD, which are candidate genes, may play an important role in ROS metabolism during the lignification of pear stone cells. This study not only provided insight into the molecular characteristics of the RBOH family in fruit-producing trees, but also lays the foundation for studying the role of ROS in plant lignification.

Assessment of Subcellular ROS and NO Metabolism in Higher Plants: Multifunctional Signaling Molecules

“…RBOH activity is involved in many plant processes including cell growth, plant development, stomatal closure, pollen tube growth, abiotic stress, symbiotic interactions, and pathogen responses [89]. It is also involved in fruit ripening [90] and stone cell lignification in fruit-producing trees [91]. RBOH's functional diversity suggests that each isozyme is characterized by a particular specialization.…”

Genome-wide identification and expression analysis of NADPH oxidase genes in response to ABA and abiotic stresses, and in fibre formation in Gossypium

“…In recent years, Rboh gene families have been characterized at genome-wide levels in many plants such as Arabidopsis, rice, wheat, Glycine max, Brassica rapa and multiple fruit trees. The expression patterns of the genes were also studied in tissues and in responding to diverse stresses (Chang et al, 2016;Hu et al, 2018;Cheng et al, 2019;Li et al, 2019a;Li et al, 2019b;Liu et al, 2019;Navathe et al, 2019;Zou, Yang & Zhang, 2019). Moreover, 2 RbohBs, 5 RbohDs (3 are RbohKs according to our classification) and 4 RbohFs in cotton have shown to be differentially expressed after infection by Verticillium dahliae (Li et al, 2019a;Li et al, 2019b).…”

Genome-Wide Comparative Analysis of the β-glucosidase Family in Five Rosaceae Species and their Potential Role on Lignification of Stone Cells in Chinese White Pear

“…The greater the diameter density of the cell mass, the more the stone cell content of pear fruit, the worse the fruit quality [32]. Stone cells are formed by secondary thickening of parenchyma cells, and lignin is one of the main components of stone cells [33,34]. Lignin is a secondary metabolite, during pear fruit development, lignin synthesis, transport and deposition are closely related to stone cell development [35,36].To this end, this study aims to conduct in-depth research on the pear BGLU genes family using bioinformatics methods on the basis of previous studies, clarify the molecular evolution characteristics of the BGLU family, and screen out β-glucosidase gene related to the development of pear stone cells and ligni cation.…”