AUTHOR=Si Zengzhi , Wang Lianjun , Ji Zhixin , Zhao Mingming , Zhang Kai , Qiao Yake 

TITLE=Comparative analysis of the MYB gene family in seven Ipomoea species

JOURNAL=Frontiers in Plant Science

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2023.1155018

DOI=10.3389/fpls.2023.1155018

ISSN=1664-462X

ABSTRACT=<p>The MYB transcription factors regulate plant growth, development, and defense responses. However, information about the <italic>MYB</italic> gene family in <italic>Ipomoea</italic> species is rare. Herein, we performed a comprehensive genome-wide comparative analysis of this gene family among seven <italic>Ipomoea</italic> species, sweet potato (<italic>I. batatas</italic>), <italic>I. trifida</italic>, <italic>I. triloba</italic>, <italic>I. nil</italic>, <italic>I. purpurea</italic>, <italic>I. cairica</italic>, and <italic>I. aquatic</italic>, and identified 296, 430, 411, 291, 226, 281, and 277 <italic>MYB</italic> genes, respectively. The identified <italic>MYB</italic> genes were classified into five types: <italic>1R</italic>-<italic>MYB</italic> (<italic>MYB</italic>-related), <italic>2R</italic>-<italic>MYB</italic> (<italic>R2R3</italic>-<italic>MYB</italic>), <italic>3R</italic>-<italic>MYB</italic> (<italic>R1R2R3</italic>-<italic>MYB</italic>), <italic>4R</italic>-<italic>MYB</italic>, and <italic>5R-MYB</italic>, and the <italic>MYB-related</italic> or <italic>R2R3</italic>-<italic>MYB</italic> type was the most abundant <italic>MYB</italic> genes in the seven species. The <italic>Ipomoea MYB</italic> genes were classed into distinct subgroups based on the phylogenetic topology and the classification of the <italic>MYB</italic> superfamily in Arabidopsis. Analysis of gene structure and protein motifs revealed that members within the same phylogenetic group presented similar exon/intron and motif organization. The identified <italic>MYB</italic> genes were unevenly mapped on the chromosomes of each <italic>Ipomoea</italic> species. Duplication analysis indicated that segmental and tandem duplications contribute to expanding the <italic>Ipomoea MYB</italic> genes. Non-synonymous substitution (Ka) to synonymous substitution (Ks) [Ka/Ks] analysis showed that the duplicated <italic>Ipomoea MYB</italic> genes are mainly under purifying selection. Numerous <italic>cis</italic>-regulatory elements related to stress responses were detected in the <italic>MYB</italic> promoters. Six sweet potato transcriptome datasets referring to abiotic and biotic stresses were analyzed, and <italic>MYB</italic> different expression genes’ (DEGs’) responses to stress treatments were detected. Moreover, 10 sweet potato <italic>MYB</italic> DEGs were selected for qRT-PCR analysis. The results revealed that four responded to biotic stress (stem nematodes and <italic>Ceratocystis fimbriata</italic> pathogen infection) and six responded to the biotic stress (cold, drought, and salt). The results may provide new insights into the evolution of <italic>MYB</italic> genes in the <italic>Ipomoea</italic> genome and contribute to the future molecular breeding of sweet potatoes.</p>