Leibniz-Institute of Vegetable and Ornamental Crops, Theodor-Echtermeyer-Weg 1, D-14979 Grossbeeren, Germany.
J Plant Physiol. 2011 Jul 15;168(11):1256-63. doi: 10.1016/j.jplph.2011.01.026. Epub 2011 Apr 13.
Arbuscular mycorrhizal fungi enhance CO₂ assimilation of their hosts which ensure the demand for carbohydrates of these obligate biotrophic microorganisms. Photosynthetic parameters were measured in tomato colonised or not by the arbuscular mycorrhizal fungus Glomus mosseae. In addition, carbohydrate contents and mRNA accumulation of three sucrose transporter genes were analysed. Mycorrhizal plants showed increased opening of stomata and assimilated significant more CO₂. A higher proportion of the absorbed light was used for photochemical processes, while non-photochemical quenching and the content of photoprotective pigments were lower. Analysis of sugar contents showed no significant differences in leaves but enhanced levels of sucrose and fructose in roots, while glucose amounts stayed constant. The three sucrose transporter encoding genes of tomato SlSUT1, SlSUT2 and SlSUT4 were up-regulated providing transport capacities to transfer sucrose into the roots. It is proposed that a significant proportion of sugars is used by the mycorrhizal fungus, because only amounts of fructose were increased, while levels of glucose, which is mainly transferred towards the fungus, were nearly constant.
丛枝菌根真菌增强了其宿主对二氧化碳的同化作用，从而确保了这些专性生物营养型微生物对碳水化合物的需求。对被丛枝菌根真菌摩西球囊霉（Glomus mosseae）定殖或未定殖的番茄进行了光合作用参数的测量。此外，还分析了三种蔗糖转运蛋白基因的碳水化合物含量和 mRNA 积累。菌根植物的气孔开度增加，同化的二氧化碳显著增多。更多的吸收光被用于光化学过程，而非光化学猝灭和光保护色素的含量较低。糖含量分析表明叶片中没有显著差异，但根中蔗糖和果糖的含量增加，而葡萄糖的含量保持不变。番茄 SlSUT1、SlSUT2 和 SlSUT4 三种蔗糖转运蛋白编码基因的上调为将蔗糖转运到根部提供了转运能力。据推测，相当一部分的糖被菌根真菌利用，因为只有果糖的含量增加，而主要向真菌转移的葡萄糖含量几乎不变。
