Abstract
The R2R3MYB proteins represent one of the largest families of transcription factors, which play important roles in plant growth and development. Although genome-wide analysis of this family has been conducted in many species, little is known about R2R3MYB genes in citrus, In this study, 101 R2R3MYB genes has been identified in the citrus (Citrus sinesis and Citrus clementina) genomes, which are almost equal to the number of rice. Phylogenetic analysis revealed that they could be subdivided into 21 subgroups. The evolutionary relationships and the intro-exon organizations were also analyzed, revealing strong gene conservation but also the expansions of particular functional genes during the plant evolution. Tissue-specific expression profiles showed that 95 citrus R2R3MYB genes were expressed in at least one tissue and the other 6 genes showed very low expression in all tissues tested, suggesting that citrus R2R3MYB genes play important roles in the development of all citrus organs. The transcript abundance level analysis during abiotic conditions (NaCl, abscisic acid, jasmonic acid, drought and low temperature) identified a group of R2R3MYB genes that responded to one or multiple treatments, which showed a promising for improving citrus adaptation to stresses. Our results provided an essential foundation for the future selection of the citrus R2R3MYB genes for cloning and functional dissection with an aim of uncovering their roles in citrus growth and development.
Highlights
MYB gene family is large, functionally diverse and present in all eukaryotes, the proteins encoding by which usually function as transcription factors with MYB binding domain conferring the ability to bind DNA
One hundred and twenty-six Arabidopsis R2R3MYB proteins were used as a query to search against the citrus genomes at the Join Genome Institute (JGI) with BLASTP program
The size of the R2R3family in citrus was smaller than that of Arabidopsis (126) [5], populus (197) [7], grape (117) [6], maize (157) [4] and soybean (244) [3], was almost equal to that of rice (102) [5], and was larger than that of cucumber (55) [2], suggesting the R2R3MYB gene family in citrus had shrink compared to Arabidopsis, polar, grape and soybean, but expanded compared to cucumber. the number of R2R3MYB genes in our study may be true, considering that the total gene number predicted in Citrus Sinensis or Citrus clementina (24533) is even lower than that in Arabidopsis (26819)
Summary
MYB gene family is large, functionally diverse and present in all eukaryotes, the proteins encoding by which usually function as transcription factors with MYB binding domain conferring the ability to bind DNA. Based on the number of repeat(s) in the MYB domain, MYB proteins are divided into four types: 4RMYB contains four repeats, 3RMYB (R1R2R3MYB) has three consecutive repeats, R2R3MYB possesses two repeats, and the MYB-related type usually, but not always, has a single repeat [2]. Among these four types, R2R3MYB is specific to higher plants and quantitatively predominant in most plants, which is characterized by the presence of a conserved MYB domain and a highly variable C-terminal region [3, 4]. The expansion of the R2R3MYB transcription factors in plants is well favor of the observation that numerous R2R3MYB proteins play central roles in plant-specific processes [7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
