Southern Cross Plant Science, Southern Cross University, PO Box 57 Lismore NSW 2480, Australia.
International Rice Research Institute (IRRI), Crop and Environmental Sciences Division, 7777 Metro Manila, Philippines.
J Integr Plant Biol. 2015 Nov;57(11):969-79. doi: 10.1111/jipb.12435.
Phosphorus (P) is a major plant nutrient and developing crops with higher P-use efficiency is an important breeding goal. In this context we have conducted a comparative study of irrigated and rainfed rice varieties to assess genotypic differences in colonization with arbuscular mycorrhizal (AM) fungi and expression of different P transporter genes. Plants were grown in three different soil samples from a rice farm in the Philippines. The data show that AM symbiosis in all varieties was established after 4 weeks of growth under aerobic conditions and that, in soil derived from a rice paddy, natural AM populations recovered within 6 weeks. The analysis of AM marker genes (AM1, AM3, AM14) and P transporter genes for the direct Pi uptake (PT2, PT6) and AM-mediated pathway (PT11, PT13) were largely in agreement with the observed root AM colonization providing a useful tool for diversity studies. Interestingly, delayed AM colonization was observed in the aus-type rice varieties which might be due to their different root structure and might confer an advantage for weed competition in the field. The data further showed that P-starvation induced root growth and expression of the high-affinity P transporter PT6 was highest in the irrigated variety IR66 which also maintained grain yield under P-deficient field conditions.
磷（P）是一种主要的植物养分，提高作物的磷利用效率是一个重要的育种目标。在这种情况下，我们对灌溉和雨养水稻品种进行了比较研究，以评估丛枝菌根（AM）真菌定殖和不同磷转运基因表达的基因型差异。植物在菲律宾一个水稻农场的三种不同土壤样本中生长。数据表明，在有氧条件下生长 4 周后，所有品种都建立了 AM 共生关系，并且在来自水稻田的土壤中，自然 AM 种群在 6 周内恢复。对 AM 标记基因（AM1、AM3、AM14）和直接 Pi 吸收（PT2、PT6）和 AM 介导途径（PT11、PT13）的 P 转运基因的分析与观察到的根 AM 定殖基本一致，为多样性研究提供了有用的工具。有趣的是，aus 型水稻品种的 AM 定殖延迟，这可能是由于它们不同的根结构，并且可能在田间杂草竞争中具有优势。数据还表明，缺磷诱导根生长，高亲和力 P 转运体 PT6 的表达在灌溉品种 IR66 中最高，IR66 也在缺磷田间条件下保持了籽粒产量。
