Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Frederiksberg, Denmark.
Cell Microbiol. 2019 Dec;21(12):e13091. doi: 10.1111/cmi.13091. Epub 2019 Aug 14.
Many biotrophic fungal plant pathogens develop feeding structures, haustoria, inside living plant cells, which are essential for their success. Extrahaustorial membranes (EHMs) surround haustoria and delimit the extrahaustorial matrices (EHMxs). Little is known about transport mechanisms across EHMs and what properties proteins and nutrients need in order to cross these membranes. To investigate this further, we expressed fluorescent proteins in the cytosol of infected barley leaf epidermal cells after particle bombardment and investigated properties that influenced their localisation in the powdery mildew EHMx. We showed that this translocation is favoured by a neutral isoelectric point (pI) between 6.0 and 8.4. However, for proteins larger than 50 kDa, pI alone does not explain their localisation, hinting towards a more complex interplay between pI, size, and sequence properties. We discuss the possibility that an EHM translocon is involved in protein uptake into the EHMx.
许多生物营养型真菌植物病原体在活植物细胞内形成营养结构——吸器，这对于它们的成功至关重要。细胞外结构膜（EHMs）围绕着吸器并限定了细胞外基质（EHMsx）的范围。关于穿过 EHMs 的运输机制以及蛋白质和营养物质需要具备哪些特性才能穿过这些膜，我们知之甚少。为了进一步研究这一问题，我们通过粒子轰击在感染大麦叶片表皮细胞的细胞质中表达荧光蛋白，并研究了影响其在白粉菌 EHMx 中定位的特性。我们发现，这种易位受中性等电点（pI）在 6.0 到 8.4 之间的影响。然而，对于大于 50 kDa 的蛋白质来说，pI 本身并不能解释它们的定位，这表明 pI、大小和序列特性之间存在更复杂的相互作用。我们讨论了一种可能性，即 EHM 转运蛋白可能参与了蛋白质进入 EHMx 的过程。
