低pH对丛枝菌根中丛枝发育与功能的影响及其激素调控机制

华南酸性红壤约占我国国土面积的近1/3，其低pH、养分贫乏等不利因素极大地制约着作物生产潜力的充分发挥。丛枝菌根真菌（AMF）能够提高植物对低pH的抗性，是酸性红壤土壤改良的重要生物资源。丛枝是AMF与根细胞之间进行物质交换的关键结构，因此是AMF发挥功能的核心所在，然而，低pH对丛枝的发育和功能的影响及其作用模式目前尚不清晰。植物激素在丛枝的形成中起到重要的调控作用，是否参与了低pH对丛枝发育与功能调控目前不得而知。本研究以此为背景，以番茄为宿主植物，拟通过沙培试验、根器官培养等，通过测定丛枝侵染率、ALP、聚磷酸盐累积、丛枝特异性诱导的磷酸转运蛋白的表达等，研究低pH对不同AMF菌株的丛枝发育与功能的影响；通过测定植物组织中生长素、ABA、GAs含量以及对应的合成或运输相关基因的表达，并使用不同激素突变体，研究激素在低pH影响丛枝发育与功能中的调控机制。

Acidic red soils in southern China account for nearly one third of Chinese terrestrial area, where adverse conditions such as low pH and low contents of nutrients greatly limit the potential production of crops. Arbuscular mycorrhizal fungi (AMF) can increase the resistance of plants to low pH, and thus function as important biological resource for the improvement of acidic soils. Arbuscules are the key structure for the nutrition exchange between AMF and root cells, as well as the core of AMF's functioning, however, the effects of low pH on the development and functioning of arbuscules and the effect patterns are still uncertain. Phytohormones play an important regulating role in the formation of arbuscules, even so, it is less established wheather phytohormones are involved in the effects of low pH on the development and functioning of arbuscules. In this study, taking tomato (Solanum lycopersicum) as host plant, we will monitor the arbuscular infection rate, ALP activity, polyphosphate accumulation, the expression of arbuscule-specifically induced phosphate transporter and other parameters in sand culture and root culture, in order to reveal the effects of low pH on the development and functioning of different AMF strains. We will also analyze the contents of auxin, ABA, GAs in plant tissues and the expressions of the respective genes coding the biosynthesis or polar transport of phytohormones, and use the tomato mutants of different phytohormones, in order to elucidate the regulating mechanisms of phytohormones involved in the effects of low pH on the development and functioning of arbuscules.