AUTHOR=Meng Chengsheng , Yan Yuanyuan , Liu Zhengwen , Chen Liting , Zhang Yan , Li Xiuxin , Wu Liqiang , Zhang Guiyin , Wang Xingfen , Ma Zhiying 

TITLE=Systematic Analysis of Cotton Non-specific Lipid Transfer Protein Family Revealed a Special Group That Is Involved in Fiber Elongation

JOURNAL=Frontiers in Plant Science

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2018.01285

DOI=10.3389/fpls.2018.01285

ISSN=1664-462X

ABSTRACT=<p>Non-specific lipid transfer proteins (nsLTPs) had been previously isolated from cotton fiber but their functions were unclear so far. Bioinformatic analysis of the tetraploid cotton genome database identified 138 <italic>nsLTP</italic> genes, falling into the 11 groups as reported previously. Different from <italic>Arabidopsis</italic>, cacao, and other crops, cotton type XI genes were considerably expanded and diverged earlier on chromosome At11, Dt11, and Dt08. Corresponding to the type XI genes, the type XI proteins (GhLtpXIs) all contained an extra N-terminal cap resulting in larger molecular weight. The research revealed that the expression of type XI genes was dramatically increased in fibers of tetraploid cotton compared with the two diploid progenitors. High-level of <italic>GhLtpXIs</italic> expression was observed in long-fibered cotton cultivars during fiber elongation. Ectopic expression of <italic>GhLtpXIs</italic> in <italic>Arabidopsis</italic> significantly enhanced trichome length, suggesting that <italic>GhLtpXIs</italic> promoted fiber elongation. Overall, the findings of this research provide insights into phenotypic evolution of <italic>Gossypium</italic> species and regulatory mechanism of nsLTPs during fiber development.</p><p><bold>HIGHLIGHT</bold></p><p>A specific group, type XI nsLTPs, was identified with predominant expression in elongating fibers of <italic>Gossypium hirsutum</italic> based on evolutionary, transcriptional, and functional analyses.</p>