Conservation of the Ustilago maydis effector See1 in related smuts

Abstract

Ustilago maydis is a biotrophic fungus that induces formation of tumors in maize (Zea mays L). In a recent study we identified See1 (Seedling efficient effector 1) as an U. maydis organ-specific effector required for tumor formation in leaves. See1 is required for U. maydis induced reactivation of plant DNA synthesis during leaf tumor progression. The protein is secreted from biotrophic hyphae and localizes to the cytoplasm and nucleus of plant cell. See1 interacts with maize SGT1, a cell cycle and immune regulator, interfering with its MAPK-triggered phosphorylation. Here, we present new data on the conservation of See1 in other closely related smuts and experimental data on the functionality of See1 ortholog in Ustilago hordei, the causal agent of barley covered smut disease.

LOCALIZER: subcellular localization prediction of both plant and effector proteins in the plant cell

“…Of these, RTP1, SP7 and Bas107 have thus far been shown to localize to the plant nucleus 32–34 . We could not predict nuclear localization for the fungal effectors MISSP7 35 , See1 36 and Six3 37 , suggesting that these might not rely on NLSs to enter plant nuclei.…”

A complete toolset for the study of Ustilago bromivora and Brachypodium sp. as a fungal-temperate grass pathosystem

“…All of the U. maydis effectors functionally characterized or described in the literature, including Tin2, See1, Cmu1, Pep1, Pit2 and Mig1 (Djamei et al, 2011; Redkar et al, 2015a, 2015b; Hemetsbergeret al, 2012; Doehlemann et al, 2009; Mueller et al, 2013;Basse et al, 2000; Tanaka et al, 2014), share orthologs with U. bromivora (Figure 10A). The amino acid similarity between each U. maydis effector and its corresponding U. bromivora ortholog ranges from 41% for the organ specific effector See1 to 70% for the widely conserved peroxidase inhibitor effector Pep1 (Figure 10A).…”

Characterization of ApB73, a virulence factor important for colonization ofZea maysby the smutUstilago maydis

“…The reason here is probably the overall very high conservation (identities of 51%–64% compared with only 27%–44.5% for ApB73). In contrast, complementation attempts for the effector See1 with its U. hordei orthologue were not successful, with identity values of 34% (Redkar et al ., ).…”