AUTHOR=Liu Zhao , Xiong Tao , Zhao Yingwei , Qiu Bingfa , Chen Hao , Kang Xiangyang , Yang Jun 

TITLE=Genome-wide characterization and analysis of Golden 2-Like transcription factors related to leaf chlorophyll synthesis in diploid and triploid Eucalyptus urophylla

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.952877

DOI=10.3389/fpls.2022.952877

ISSN=1664-462X

ABSTRACT=<p>Golden 2-Like (<italic>GLK</italic>) transcription factors play a crucial role in chloroplast development and chlorophyll synthesis in many plant taxa. To date, no systematic analysis of <italic>GLK</italic> transcription factors in tree species has been conducted. In this study, 40 <italic>EgrGLK</italic> genes in the <italic>Eucalyptus grandis</italic> genome were identified and divided into seven groups based on the gene structure and motif composition. The <italic>EgrGLK</italic> genes were mapped to 11 chromosomes and the distribution of genes on chromosome was uneven. Phylogenetic analysis of <italic>GLK</italic> proteins between <italic>E. grandis</italic> and other species provided information for the high evolutionary conservation of <italic>GLK</italic> genes among different species. Prediction of <italic>cis</italic>-regulatory elements indicated that the <italic>EgrGLK</italic> genes were involved in development, light response, and hormone response. Based on the finding that the content of chlorophyll in mature leaves was the highest, and leaf chlorophyll content of triploid <italic>Eucalyptus urophylla</italic> was higher than that of the diploid control, <italic>EgrGLK</italic> expression pattern in leaves of triploid and diploid <italic>E. urophylla</italic> was examined by means of transcriptome analysis. Differential expression of <italic>EgrGLK</italic> genes in leaves of <italic>E. urophylla</italic> of different ploidies was consistent with the trend in chlorophyll content. To further explore the relationship between <italic>EgrGLK</italic> expression and chlorophyll synthesis, co-expression networks were generated, which indicated that <italic>EgrGLK</italic> genes may have a positive regulatory relationship with chlorophyll synthesis. In addition, three <italic>EgrGLK</italic> genes that may play an important role in chlorophyll synthesis were identified in the co-expression networks. And the prediction of miRNAs targeting <italic>EgrGLK</italic> genes showed that miRNAs might play an important role in the regulation of <italic>EgrGLK</italic> gene expression. This research provides valuable information for further functional characterization of <italic>GLK</italic> genes in <italic>Eucalyptus</italic>.</p>