Agriculture, Food and Wine, The University of Adelaide, Adelaide, South Australia, Australia.
New Phytol. 2010 Mar;185(4):1050-61. doi: 10.1111/j.1469-8137.2009.03162.x.
*We studied the effects of two arbuscular mycorrhizal (AM) fungi, singly or together, on the outcome of competition between a host (tomato cultivar, wild-type (WT)) and a surrogate nonhost (rmc, a mycorrhiza-defective mutant of WT) as influenced by the contributions of the direct and AM phosphorus (P) uptake pathways to plant P. *We grew plants singly or in pairs of the same or different genotypes (inoculated or not) in pots containing a small compartment with (32)P-labelled soil accessible to AM fungal hyphae and determined expression of orthophosphate (P(i)) transporter genes involved in both AM and direct P uptake. *Gigaspora margarita increased WT competitive effects on rmc. WT and rmc inoculated with Glomus intraradices both showed growth depressions, which were mitigated when G. margarita was present. Orthophosphate transporter gene expression and (32)P transfer showed that the AM pathway operated in single inoculated WT, but not in rmc. *Effects of AM fungi on plant competition depended on the relative contributions of AM and direct pathways of P uptake. Glomus intraradices reduced the efficiency of direct uptake in both WT and rmc. The two-fungus combination showed that interactions between fungi are important in determining outcomes of plant competition.
我们研究了两种丛枝菌根（AM）真菌单独或共同作用对宿主（番茄品种，野生型（WT））和替代非宿主（rmc，WT 的菌根缺陷突变体）之间竞争结果的影响，其影响因素包括直接和 AM 磷（P）吸收途径对植物 P 的贡献。我们在含有（32）P 标记土壤的小隔室的盆中单独或成对种植具有相同或不同基因型（接种或不接种）的植物，并用参与 AM 和直接 P 吸收的 orthophosphate（P(i)）转运基因的表达来确定。Gigaspora margarita 增加了 WT 对 rmc 的竞争效应。接种 Glomus intraradices 的 WT 和 rmc 均表现出生长抑制，而当存在 G. margarita 时则有所缓解。 orthophosphate 转运基因表达和（32）P 转移表明，AM 途径在单独接种的 WT 中起作用，但在 rmc 中不起作用。AM 真菌对植物竞争的影响取决于 AM 和直接 P 吸收途径的相对贡献。Glomus intraradices 降低了 WT 和 rmc 中直接吸收的效率。两种真菌的组合表明，真菌之间的相互作用对于确定植物竞争的结果很重要。
