Root exudates stimulate the uptake and metabolism of organic carbon in germinating spores of Glomus intraradices
Root exudates stimulate the uptake and metabolism of organic carbon in germinating spores of Glomus intraradices
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DOI：
10.1111/j.1469-8137.2008.02590.x
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发表时间：
2008-01-01
期刊：
影响因子：
9.4
通讯作者：
Shachar-Hill, Yair
中科院分区：
文献类型：
--
作者：
Buecking, Heike;Abubaker, Jehad;Shachar-Hill, Yair
根分泌物在AM真菌孢子的共生前期生长过程中起着重要作用，它能促进AM真菌孢子的分枝和分解代谢。本研究测定了根分泌物对AM真菌孢子共生前期生长、外源碳的吸收以及与孢子萌发碳代谢有关的基因pu 3的转录水平的影响。粗根分泌物对孢子萌发有轻微的促进作用，增加芽管分支，刺激乙酸盐的吸收和分解代谢，并在更大程度上刺激葡萄糖，但对基因表达没有影响。相比之下，部分纯化的根分泌物增加转录水平的酰基辅酶A脱氢酶（β-氧化脂肪酸乙酰辅酶A），苹果酸合成酶（乙醛酸循环）和谷氨酰胺-果糖-6-磷酸氨基转移酶（几丁质生物合成），但没有不同的粗根分泌物在其对底物的吸收和呼吸的影响。糖原合成酶（糖原生物合成），葡萄糖-6-磷酸脱氢酶（戊糖磷酸途径）和中性海藻糖酶（水解海藻糖）的表达只有轻微或不受根分泌物的影响。根分泌物对细胞膜活性和基因表达的影响，并讨论了与孢子在共生前期生长过程中的分解代谢和合成代谢有关的结果。
Root exudates play a key role during the presymbiotic growth phase and have been shown to stimulate hyphal branching and the catabolic metabolism of arbuscular mycorrhizal (AM) fungal spores.Here, the effect of root exudates on presymbiotic growth, uptake of exogenous carbon and transcript levels for genes putatively involved in the carbon metabolism of germinating spores were determined.Crude root exudates led to a slight acceleration of spore germination, increased germ tube branching and stimulated uptake and catabolic metabolism of acetate, and to a greater extent of glucose, but had no effect on gene expression. By contrast, partially purified root exudates increased the transcript levels of acyl-CoA dehydrogenase (beta-oxidation of fatty acids to acetyl-CoA), malate synthase (glyoxylate cycle) and glutamine-fructose-6-phosphate aminotransferase (chitin biosynthesis), but did not differ from crude root exudates in their effect on substrate uptake and respiration. The expression of glycogen synthase (glycogen biosynthesis), glucose-6-phosphate dehydrogenase (pentose phosphate pathway) and neutral trehalase (hydrolysis of trehalose) were only marginally or not affected by root exudates.Root exudates have an effect on both membrane activity and gene expression and the results are discussed in relation to the catabolic and anabolic metabolism of spores during presymbiotic growth.