AUTHOR=Lin Lili , Cao Jiaying , Du Anqiang , An Qiuli , Chen Xiaomin , Yuan Shuangshuang , Batool Wajjiha , Shabbir Ammarah , Zhang Dongmei , Wang Zonghua , Norvienyeku Justice 

TITLE=eIF3k Domain-Containing Protein Regulates Conidiogenesis, Appressorium Turgor, Virulence, Stress Tolerance, and Physiological and Pathogenic Development of Magnaporthe oryzae Oryzae

JOURNAL=Frontiers in Plant Science

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2021.748120

DOI=10.3389/fpls.2021.748120

ISSN=1664-462X

ABSTRACT=<p>The eukaryotic translation initiation factor 3 (eIF3) complex consists of essential and non-essential sub-complexes. Non-essential eIF3 complex subunits, such as eIF3e, eIF3j, eIF3k, and eIF3l, modulate stress tolerance and enhance the lifespan of <italic>Neurospora crassa</italic> and <italic>Caenorhabditis elegans</italic>. However, there is limited knowledge of the role of the non-essential eIF3 sub-complex in the pathophysiological development of plant fungal pathogens. Here, we deployed genetic and biochemical techniques to explore the influence of a hypothetical protein containing eIF3k domain in <italic>Magnaporthe oryzae Oryzae</italic> (<italic>MoOeIF3k</italic>) on reproduction, hyphae morphogenesis, stress tolerance, and pathogenesis. Also, the targeted disruption of <italic>MoOeIF3k</italic> suppressed vegetative growth and asexual sporulation in Δ<italic>Mo</italic>O<italic>eif3k</italic> strains significantly. We demonstrated that <italic>MoOeIF3k</italic> promotes the initiation and development of the rice blast disease by positively regulating the mobilization and degradation of glycogen, appressorium integrity, host penetration, and colonization during host–pathogen interaction. For the first time, we demonstrated that the eIF3k subunit supports the survival of the blast fungus by suppressing vegetative growth and possibly regulating the conversions and utilization of stored cellular energy reserves under starvation conditions. We also observed that the deletion of <italic>MoOeIF3k</italic> accelerated ribosomal RNA (rRNA) generation in the Δ<italic>Mo</italic>O<italic>eif3k</italic> strains with a corresponding increase in total protein output. In summary, this study unravels the pathophysiological significance of eIF3k filamentous fungi. The findings also underscored the need to systematically evaluate the individual subunits of the non-essential eIF3 sub-complex during host–pathogen interaction. Further studies are required to unravel the influence of synergetic coordination between translation and transcriptional regulatory machinery on the pathogenesis of filamentous fungi pathogens.</p>