Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
Int J Mol Sci. 2019 Jul 25;20(15):3636. doi: 10.3390/ijms20153636.
Nitrogen (N) is one of the indispensable factors in rice growth and development. China holds a premier position in the production of rice and at the same time also faces higher N fertilizer costs along with serious damage to the environment. A better solution is much needed to address these issues, without disrupting the production of rice as an important cereal, while minimizing all the deleterious effects on the environment. Two isogenic lines Kitaake (WT) and its genetically modified line CIPK2 (RC), overexpressing the gene for Calcineurin B-like interacting protein kinase 2 (Os) with better nitrogen use efficiency (NUE), were compared for their growth and development under low versus normal levels of N. NUE is a complex trait mainly related to a plant's efficiency in extraction, assimilation, and recycling of N from soil. The microbial population was analyzed using high-throughput Illumina Miseq 16S rRNA sequencing and found that RC with specifically expressed in rice root, not only performed better without nitrogen fertilizer (LN) but also increased the diversity of bacterial communities in rice rhizosphere compartments (rhizosphere, rhizoplane, and endosphere). The relative abundance of beneficial bacteria phyla increased, which are known to promote the circulation and transformation of N in rhizosphere soil. To further explore the potential of RC regarding better performance under LN, the ion fluxes in root apical were detected by non-invasive micro-test technique (NMT). We found that RC can absorb more Ca and NO under LN as compared to WT. Finally, compared to WT, RC plants exhibited better growth of root and shoot, and increased yield and N uptake under LN, whereas there was no significant difference in the growth of two rice lines under normal nitrogen (NN) treatment. We are able to get preliminary results, dealing with the overexpressed rice line, by studying the rice molecular, physiological, and chemical parameters related to NUE. The results laid the foundation for further research on N absorption and utilization in rice from the soil and the interaction with microbial communities.
氮（N）是水稻生长发育所必需的因素之一。中国在水稻生产方面处于领先地位，但同时也面临着更高的氮肥成本和严重的环境破坏。需要找到更好的解决方案来解决这些问题，同时不影响水稻作为重要粮食作物的生产，并且最大限度地减少对环境的所有有害影响。
本研究选用氮高效利用（NUE）相关的拟南芥钙调神经磷酸酶 B 类似蛋白相互作用激酶 2（Os）基因过表达的两个水稻近等基因系 Kitaake（WT）和 CIPK2（RC）进行研究。NUE 是一个复杂的性状，主要与植物从土壤中提取、同化和再利用氮的效率有关。通过高通量 Illumina Miseq 16S rRNA 测序技术对微生物种群进行分析发现，RC 根系特异表达，不仅在无氮条件下（LN）表现更好，而且增加了水稻根际区（根际、根面和根内）细菌群落的多样性。有益细菌门的相对丰度增加，这些细菌被认为可以促进根际土壤中氮的循环和转化。为了进一步探索 RC 在 LN 下更好表现的潜力，我们采用非侵入性微测试技术（NMT）检测了根尖的离子通量。结果发现，与 WT 相比，RC 在 LN 条件下可以吸收更多的 Ca 和 NO。最后，与 WT 相比，RC 植株在 LN 条件下具有更好的根和地上部分生长，增加了产量和氮吸收，而在 NN 处理下两条水稻线的生长没有显著差异。
通过研究与 NUE 相关的水稻分子、生理和化学参数，我们获得了关于过表达水稻系的初步结果。这些结果为进一步研究水稻从土壤中吸收和利用氮以及与微生物群落的相互作用奠定了基础。
