Transcripts for genes encoding soluble acid invertase and sucrose synthase accumulate in root tip and cortical cells containing mycorrhizal arbuscules
Transcripts for genes encoding soluble acid invertase and sucrose synthase accumulate in root tip and cortical cells containing mycorrhizal arbuscules
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DOI：
10.1023/a:1016038010393
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发表时间：
2002-09-01
影响因子：
5.1
通讯作者：
Anderson, AJ
中科院分区：
文献类型：
--
作者：
Blee, KA;Anderson, AJ
由丛枝菌根真菌根内球囊霉（Glomus intraradices（Schenck & Smith））形成的丛枝仅限于紧邻内皮层的皮层细胞。因为这些皮层细胞是第一个拦截离开维管的光合产物，蔗糖代谢酶的转录水平进行了比较菌根和非菌根根。该探针对应于编码可溶性酸性转化酶的基因，该酶具有潜在的液泡靶向，我们从菜豆根、大豆根瘤菌响应性蔗糖合成酶和胡萝卜细胞壁酸性转化酶产生。在非菌根根中的转录本发育调节和丰富的根尖中的所有三个探针，但在分化的根的P. vulgaris，他们主要位于韧皮部组织的蔗糖合成酶或内皮层和韧皮部的可溶性酸性转化酶。在菌根根中，蔗糖合成酶和液泡转化酶的转录物的积累增加，都观察到在相同的皮质细胞轴承丛发荧光。在含丛枝的荧光胡萝卜细胞中，对细胞壁转化酶基因的表达没有影响。因此，似乎荧光丛枝细胞中真菌菌丝的存在刺激蔗糖代谢酶表达的离散改变，以增加细胞的汇潜力。
Arbuscule formation by the arbuscular mycorrhizal fungus Glomus intraradices (Schenck & Smith) was limited to cortical cells immediately adjacent to the endodermis. Because these cortical cells are the first to intercept photosynthate exiting the vascular cylinder, transcript levels for sucrose metabolizing-enzymes were compared between mycorrhizal and non-mycorrhizal roots. The probes corresponded to genes encoding a soluble acid invertase with potential vacuolar targeting, which we generated from Phaseolus vulgaris roots, a Rhizobium-responsive sucrose synthase of soybean and a cell wall acid invertase of carrot. Transcripts in non-mycorrhizal roots were developmentally regulated and abundant in the root tips for all three probes but in differentiated roots of P. vulgaris they were predominantly located in phloem tissues for sucrose synthase or the endodermis and phloem for soluble acid invertase. In mycorrhizal roots increased accumulations of transcripts for sucrose synthase and vacuolar invertase were both observed in the same cortical cells bearing arbuscules that fluoresce. There was no effect on the expression of the cell wall invertase gene in fluorescent carrot cells containing arbuscules. Thus, it appears that presence of the fungal hyphae in the fluorescent arbusculated cell stimulates discrete alterations in expression of sucrose metabolizing enzymes to increase the sink potential of the cell.