Genome-Wide Identification, Evolution, and Comparative Analysis of B-Box Genes in Brassica rapa, B. oleracea, and B. napus and Their Expression Profiling in B. rapa in Response to Multiple Hormones and Abiotic Stresses.

Sonam Singh,Yinbo Ma,Sushil Satish Chhapekar,Jusang Kim,Yong Pyo Lim,Sang Heon Oh,Jana Jeevan Rameneni,Su Ryun Choi

doi:10.3390/ijms221910367

Sonam Singh, Yinbo Ma + Show 6 more

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https://doi.org/10.3390/ijms221910367

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Abstract

The B-box zinc-finger transcription factors are important for plant growth, development, and various physiological processes such as photomorphogenesis, light signaling, and flowering, as well as for several biotic and abiotic stress responses. However, there is relatively little information available regarding Brassica B-box genes and their expression. In this study, we identified 51, 52, and 101 non-redundant genes encoding B-box proteins in Brassica rapa (BrBBX genes), B. oleracea (BoBBX genes), and B. napus (BnBBX genes), respectively. A whole-genome identification, characterization, and evolutionary analysis (synteny and orthology) of the B-box gene families in the diploid species B. rapa (A genome) and B. oleracea (C genome) and in the allotetraploid species B. napus (AC genome) revealed segmental duplications were the major contributors to the expansion of the Brassica BBX gene families. The Brassica BBX genes were classified into five subgroups according to phylogenetic relationships, gene structures, and conserved domains. Light-responsive cis-regulatory elements were detected in many of the BBX gene promoters. Additionally, BrBBX expression profiles in different tissues and in response to various abiotic stresses (heat, cold, salt, and drought) or hormones (abscisic acid, methyl jasmonate, and gibberellic acid) were analyzed by qRT-PCR. The data indicated that many B-box genes (e.g., BrBBX13, BrBBX15, and BrBBX17) may contribute to plant development and growth as well as abiotic stress tolerance. Overall, the identified BBX genes may be useful as functional genetic markers for multiple stress responses and plant developmental processes.

Highlights

The Hidden Markov Model as well as the A. thaliana BBX gene sequences obtained from the The Arabidopsis Information Resource (TAIR) database were used to identify the BBX gene family members in B. rapa, B. oleracea, and B. napus
101 BBX genes were identified in B. rapa, B. oleracea, and B. napus, respectively, after the redundant sequences were eliminated (Table 1)
We proved that Brassica BBX genes are highly responsive to various simulated stresses and hormones, including drought, mannitol, PEG, salt, cold, heat, abscisic acid (ABA), GA3 and methyl jasmonate (MeJA), implying BBX genes contribute to multiple stress responses in Brassica species

Summary

Introduction

The B-box (BBX) genes have recently been revealed to encode multifarious zincfinger transcription factors with diverse functions in several plant species [1,2]. The BBX transcription factor family members are major contributors to several activities, including the photoperiod-related regulation of flowering, plant developmental processes, seedling photomorphogenesis, seed germination, and abiotic and biotic stress responses [3]. BBX transcription factors have one or two N-terminal BBX domains with or without a. C-terminal CCT domain (COL-like/CO or TOC1 motif), unlike the corresponding proteins in animals, which include a RING finger and a coiled-coil domain along with the BBX domain.

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