AM真菌和溶磷真菌联合作用对植物耐盐性的影响及机制

Arbuscular mycorrhizal (AM) fungi and phosphate-solubilizing fungi (PSF) have closely relationship in soil, which affect the ecological functions of AM fungi significantly through their complementarities of morphological and physiological. This "cooperative relationship" is significant for the improvement of salt tolerance of plants and soil quality, however, the effect and mechanism of co-inoculation (AM fungi and PSF) on plant growth in saline stress is still unclear now. We have isolated and screened one rhizosphere microbe XJ-7, with good abilities to phosphate solubilization and salt tolerance. In this study, the AM fungi community and XJ-7 strain are being inoculated alone or co-inoculated in different salinized soils by pot experiments. The AM fungi community will be analyzed by the high throughput sequencing technology, the ecological drivers of AM fungi community composition and structure will be determined by the effect of biotic factor (XJ-7 strain) and abiotic factor (saline soil) on the diversity and phylogeny of AM fungi. The metabolic activity in plants after treated with the co-inoculation are being monitored with physiological properties, antioxidant enzymatic activities and differentially expressed protein of plants. In general, we should carry out integrative analyses on the relationship of “PSF-AMF-Plant” by ecological and physiological studies, these results will help understand the effect and mechanism of AM fungi and PSF in rhizosphere on the tolerance of plant to saline soil.

丛枝菌根（AM）真菌与土壤中溶磷真菌的关系密切，两者通过形态上和生理上的互补深刻影响着AM真菌生态功能的发挥。尤其在盐渍化土壤中，这种“合作关系”可以显著改善植物耐盐性和土壤质量，但是目前双菌联合作用机制仍缺乏足够认识。项目前期已筛选到1株溶磷耐盐真菌XJ-7，本项目拟用这株真菌与土著AM真菌群落在不同盐渍化土壤中进行单一接种和复合接种研究。通过高通量测序分析AM真菌群落多样性和谱系结构对生物因素（溶磷真菌）和非生物因素（盐渍化土壤）的响应，揭示AM真菌群落组成的驱动因素和关键生态机制。结合植株生理特性、抗氧化酶活性以及差异蛋白表达量的分析，进一步阐明双菌联合作用对植物体内代谢活动的调控过程。本项目从“溶磷真菌-AM真菌-植物”三者的关系出发，综合利用生态学和生理学的研究方法，深入解析盐渍化土壤中根际AM真菌和溶磷真菌联合作用与植物的互作机制。

促生菌广泛存在作物根际，可以显著提高作物生长和养分平衡，尤其在胁迫环境中对作物的保护意义重大。本研究主要讨论了溶磷菌和木霉菌这两类丝状真菌在玉米根际与AM真菌的相互作用以及对玉米耐盐性的影响。通过不同盆栽实验证实了木霉菌对AM真菌生长和功能的影响显著大于溶磷菌的影响，尤其是在低盐胁迫的条件下（75mMNaCl），AM真菌与木霉菌的协同效果显著，不但能够显著促进玉米生长、提高叶片中钾钠比率，同时显著提高AM真菌在根内和土壤中的生物量。溶磷菌更倾向于在高盐胁迫条件下（150和225mMNaCl）提高玉米叶绿素含量和钾钠比率。进一步利用植物代谢组分析揭示了双菌“合作”的潜在机制是增强了玉米碳水化合物代谢途径和脂肪酸代谢途径。本研究为土壤修复、改善作物营养、减少化肥用量、增强作物耐盐能力方面提供了优势菌株。尽管在农田生态系统中AM真菌与木霉菌的双菌“合作”关系可能会被其它微生物削弱，但是通过人为添加功能菌株作为微生物调理剂对于提高渍化土壤中玉米生长具有重要意义。