AUTHOR=Zhang Xiaohong , Zhao Junjie , Wu Xiangyuan , Hu Genhai , Fan Shuli , Ma Qifeng 

TITLE=Evolutionary Relationships and Divergence of KNOTTED1-Like Family Genes Involved in Salt Tolerance and Development in Cotton (Gossypium hirsutum L.)

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.774161

DOI=10.3389/fpls.2021.774161

ISSN=1664-462X

ABSTRACT=<p>The KNOX (KNOTTED1-like homeobox) transcription factors play an important role in leaf, shoot apical meristem and seed development and respond to biotic and abiotic stresses. In this study, we analyzed the diversity and evolutionary history of the <italic>KNOX</italic> gene family in the genome of tetraploid cotton (<italic>Gossypium hirsutum</italic>). Forty-four putative <italic>KNOX</italic> genes were identified. All <italic>KNOX</italic> genes from seven higher plant species were classified into KNOXI, KNOXII, and KNATM clades based on a phylogenetic analysis. Chromosomal localization and collinearity analysis suggested that whole-genome duplication and a polyploidization event contributed to the expansion of the cotton <italic>KNOX</italic> gene family. Analyses of expression profiles revealed that the <italic>GhKNOX</italic> genes likely responded to diverse stresses and were involved in cotton growth developmental processes. Silencing of <italic>GhKNOX2</italic> enhanced the salt tolerance of cotton seedlings, whereas silencing of <italic>GhKNOX10</italic> and <italic>GhKNOX14</italic> reduced seedling tolerance to salt stress. Silencing of <italic>GhSTM3</italic> influenced the cotton flowering time and plant development. These findings clarify the evolution of the cotton <italic>KNOX</italic> gene family and provide a foundation for future functional studies of KNOX proteins in cotton growth and development and response to abiotic stresses.</p>