AUTHOR=Guo Ting , Wang Xiao-Wen , Shan Kun , Sun Wenxian , Guo Li-Yun 

TITLE=The Loricrin-Like Protein (LLP) of Phytophthora infestans Is Required for Oospore Formation and Plant Infection

JOURNAL=Frontiers in Plant Science

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2017.00142

DOI=10.3389/fpls.2017.00142

ISSN=1664-462X

ABSTRACT=<p>Loricrin-like protein (LLP) is characterized by a high content of glycine residues and is a major component of plant cell wall. Here, we identified a <italic>Phytophthora infestans</italic> ortholog of plant <italic>LLP</italic>, named <italic>PiLLP</italic>. In <italic>P. infestans, PiLLP</italic> is strongly expressed in asexual and sexual developmental stages, including in sporangia, zoospores and germinating cysts, and during oospore formation, as well as in the early stages of infection and during hydrogen peroxide stress. Compared with the wild type, the <italic>PiLLP</italic>-silenced transformants were defective in oospore formation, had slower colony expansion rates, produced less sporangia with lower germination and zoospore-release rates, and were more sensitive to hydrogen peroxide. Moreover, Nile red staining, and <italic>PiLLP</italic>-red fluorescent protein fusions indicated that PiLLP is involved in oogonia formation. The silenced transformants also had severely diminished virulence levels that could be partially restored with diphenyleneiodium treatments. The analysis of catalase activity showed a decrease of catalase activity in silenced transformants. Thus, <italic>PiLLP</italic> is important for sexual and asexual reproduction, and is required for oxidative stress tolerance and plant infection.</p>