Fig. 2.

Jasmonate/Ethylene signaling inducer 1 (Jsi1) is a secreted effector that is targeted to the plant cell nucleus. (a) Jsi1 is secreted in axenic culture. We expressed Jsi1‐3xHA in the Ustilago maydis strain AB33. Proteins from filamentous cells and culture supernatants were subjected to Western blot analysis using anti‐hemagglutinin (HA) and anti‐actin antibodies. We used actin as a control of cell lysis, and it was only detected in whole‐cell extracts (C). Jsi1‐3xHA was detected in whole cell extracts (C) and culture supernatants (S). (b) Jsi1‐mCherry is secreted by U. maydis in maize. Confocal images of infected maize leaves 3 d postinfection with SG200Δjsi1‐Jsi1‐mCherry and SG200Δjsi1‐Jsi1₂₇₆₄₁‐mCherry (a nonsecreted version of Jsi1). Bars, 10 µm. (c) Jsi1 localizes to the nucleus of maize cells. Maize cells expressing Jsi1₂₇₆₄₁‐mCherry and green fluorescent protein–nuclear localization signal (GFP‐NLS) as a nuclear marker after biolistic transformation of leaves. (d) Jsi1 and ZmTPL1 co‐localize in the nucleus of maize leaf cells. Maize cells expressing Jsi1₂₇₆₄₁‐mCherry and ZmTPL1‐GFP. The yellow arrow indicates the transformed cell with the gold particle inside the nucleus. Bars, 20 µm.