Search

Abstract Background Studies have demonstrated that BBX (B-BOX) genes play crucial roles in regulatory networks controlling plant growth, developmental processes and stress response. Nevertheless, comprehensive study of BBX genes in orchids (Orchidaceae) is not well studied. The newly released genome sequences of Dendrobium officinale and Phalaenopsis equestris have allowed a systematic analysis of these important BBX genes in orchids. Results Here we identified 19 (DoBBX01–19) and 16 (PeBBX01–16) BBX genes from D. officinale and P. equestris, respectively, and clustered into five clades (I-V) according to phylogenetic analysis. Thirteen orthologous, two DoBBXs paralogous and two PeBBXs paralogous gene pairs were validated. This gene family mainly underwent purifying selection, but five domains experienced positive selection during evolution. Noteworthy, the expression patterns of root, root_tips, stem, leaf, speal, column, lip, and flower_buds revealed that they might contribution to the formation of these tissues. According to the cis-regulatory elements analysis of BBX genes, qRT-PCR experiments were carried out using D. officinale PLBs (protocorm-like bodies) and displayed that these BBX genes were differentially regulated under AgNO3, MeJA (Methyl Jasmonate), ABA (abscisic acid) and SA (salicylic acid) treatments. Conclusions Our analysis exposed that DoBBX genes play significant roles in plant growth and development, and response to different environmental stress conditions of D. officinale, which provide aid in the selection of appropriate candidate genes for further functional characterization of BBX genes in plants.

Abstract Background The B-BOX (BBX) proteins have important functions in regulating plant growth and development. In plants, the BBX gene family has been identified in several plants, such as rice, Arabidopsis and tomato. However, there still lack a genome-wide survey of BBX genes in pear. Results In the present study, a total of 25 BBX genes were identified in pear (Pyrus bretschneideri Rehd.). Subsequently, phylogenetic relationship, gene structure, gene duplication, transcriptome data and qRT-PCR were conducted on these BBX gene members. The transcript analysis revealed that twelve PbBBX genes (48%) were specifically expressed in pear pollen tubes. Furthermore, qRT-PCR analysis indicated that both PbBBX4 and PbBBX13 have potential role in pear fruit development, while PbBBX5 should be involved in the senescence of pear pollen tube. Conclusions This study provided a genome-wide survey of BBX gene family in pear, and highlighted its roles in both pear fruits and pollen tubes. The results will be useful in improving our understanding of the complexity of BBX gene family and functional characteristics of its members in future study.