Specific lipoxygenase isoforms accumulate in distinct regions of soybean pod walls and mark a unique cell layer
Specific lipoxygenase isoforms accumulate in distinct regions of soybean pod walls and mark a unique cell layer
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DOI：
10.1104/pp.123.4.1269
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发表时间：
2000-08-01
期刊：
影响因子：
7.4
通讯作者：
Grimes, HD
中科院分区：
文献类型：
--
作者：
Dubbs, WE;Grimes, HD
发育中的种子构成了植物的一个强大的库，并依赖于碳和氮同化物的周转和动员来提供其成熟所需的营养。这些营养物质大部分来自营养器官，包括叶片和豆荚壁。大豆（Glycine max L.）叶，其中单个同种型被认为作为活性酶或作为瞬时储存蛋白发挥作用。VLXs也是大豆豆荚壁中的主要蛋白质，占总可溶性蛋白质的约12%。检查的时间，组织，和亚细胞模式的个别VLX异构体积累和通过豆荚壁发育的脂氧合酶活性表明，VLXD是主要的VLX异构体在存储中发挥作用，在这个器官。VLXD的主要积累发生在种子填充前的内果皮中间区，从该区域提取的蛋白质显示出相对低水平的脂氧合酶活性，这表明中间区可能作为一个存储组织。另外三种VLX同种型，VLXA，VLXB和VLXC共定位于中果皮中单个离散细胞层的细胞质。因此，VLX细胞和亚细胞定位在豆荚壁的模式表明这些不同的亚型的独立功能，同时也作为一个新的细胞层在豆荚壁的特异性标记。
Developing seeds constitute a strong sink for the plant and rely on the turnover and mobilization of carbon and nitrogen assimilates to supply the nutrients needed for their maturation. In large part these nutrients emanate from the vegetative organs including leaves and pod walls. Vegetative lipoxygenases (VLXs) accumulate in the paraveinal mesophyll cell layer of soybean (Glycine max L.) leaves where individual isoforms are proposed to play a role(s) as active enzymes or as transient storage proteins. VLXs also are prominent proteins in soybean pod walls, representing approximately 12% of the total soluble protein. Examining the temporal, tissue, and subcellular patterns of individual VLX isoform accumulation and of lipoxygenase activity through pod wall development indicates that VLXD is the principal VLX isoform playing a role in storage in this organ. The major accumulation of VLXD occurs just prior to seed fill within the endocarp middle zone, and protein extracted from this region shows relatively low levels of lipoxygenase activity, suggesting the middle zone may act as a storage tissue. Three other VLX isoforms, VLXA, VLXB, and VLXC colocalize to the cytoplasm of a single discrete cell layer in the mesocarp. Thus, the patterns of VLX cellular and subcellular localization in pod walls suggest independent functions for these different isoforms while also serving as specific markers fur a novel cell layer in the pod wall.