Turner Glenn W, Grimes Howard D, Lange B Markus
Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.
School of Molecular Biosciences, Washington State University, Pullman, WA 99164-7520, USA.
Funct Plant Biol. 2011 Oct;38(10):778-787. doi: 10.1071/FP11047.
The paraveinal mesophyll (PVM) of soybean is a distinctive uniseriate layer of branched cells situated between the spongy and palisade chlorenchyma of leaves that contains an abundance of putative vegetative storage proteins, Vspα and Vspβ, in its vacuoles. Soybean vegetative lipoxygenases (five isozymes designated as Vlx(A-E)) have been reported to co-localise with Vsp in PVM vacuoles; however, conflicting results regarding the tissue-level and subcellular localisations of specific Vlx isozymes have been reported. We employed immuno-cytochemistry with affinity-purified, isozyme-specific antibodies to reinvestigate the subcellular locations of soybean Vlx isozymes during a sink limitation experiment. VlxB and VlxC were localised to the cytoplasm and nucleoplasm of PVM cells, whereas VlxD was present in the cytoplasm and nucleoplasm of mesophyll chlorenchyma (MC) cells. Label was not associated with storage vacuoles or any evident protein bodies, so our results cast doubt on the hypothesis that Vlx isozymes function as vegetative storage proteins.
大豆的脉间叶肉（PVM）是一层独特的单列分支细胞，位于叶片的海绵状和栅栏状叶肉组织之间，其液泡中含有大量假定的营养贮藏蛋白Vspα和Vspβ。据报道，大豆营养型脂氧合酶（五种同工酶，命名为Vlx(A-E)）与Vsp共定位于PVM液泡中；然而，关于特定Vlx同工酶在组织水平和亚细胞定位的结果相互矛盾。我们在库限制实验期间，使用亲和纯化的同工酶特异性抗体进行免疫细胞化学，以重新研究大豆Vlx同工酶的亚细胞定位。VlxB和VlxC定位于PVM细胞的细胞质和核质中，而VlxD存在于叶肉细胞（MC）的细胞质和核质中。标记物与贮藏液泡或任何明显的蛋白体无关，因此我们的结果对Vlx同工酶作为营养贮藏蛋白发挥作用这一假说提出了质疑。
