National Key Laboratory of Crop Genetics & Germplasm Enhancement and Utilization, Nanjing Agricultural University, Nanjing, China.
Key Laboratory of Plant Nutrition and Fertilization in Low-Middle Reaches of the Yangtze River, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China.
Plant Biotechnol J. 2023 Dec;21(12):2654-2670. doi: 10.1111/pbi.14160. Epub 2023 Aug 25.
Improving rice eating and cooking quality (ECQ) is one of the primary tasks in rice production to meet the rising demands of consumers. However, improving grain ECQ without compromising yield faces a great challenge under varied nitrogen (N) supplies. Here, we report the approach to upgrade rice ECQ by native promoter-controlled high expression of a key N-dependent floral and circadian clock regulator Nhd1. The amplification of endogenous Nhd1 abundance alters rice heading date but does not affect the entire length of growth duration, N use efficiency and grain yield under both low and sufficient N conditions. Enhanced expression of Nhd1 reduces amylose content, pasting temperature and protein content while increasing gel consistence in grains. Metabolome and transcriptome analyses revealed that increased expression of Nhd1 mainly regulates the metabolism of carbohydrates and amino acids in the grain filling stage. Moreover, expression level of Nhd1 shows a positive relationship with grain ECQ in some local main cultivars. Thus, intensifying endogenous abundance of Nhd1 is a promising strategy to upgrade grain ECQ in rice production.
提高稻米食用和蒸煮品质（ECQ）是稻米生产中满足消费者不断增长需求的主要任务之一。然而，在不同氮（N）供应下，在不影响产量的情况下提高谷物 ECQ 面临着巨大的挑战。在这里，我们报告了一种通过天然启动子控制关键的 N 依赖性花和昼夜节律钟调节剂 Nhd1 的高表达来升级稻米 ECQ 的方法。内源性 Nhd1 丰度的扩增改变了水稻抽穗期，但在低氮和充足氮条件下，不会影响整个生长时间、氮利用效率和籽粒产量。Nhd1 的增强表达降低了直链淀粉含量、糊化温度和蛋白质含量，同时增加了籽粒的凝胶稠度。代谢组学和转录组学分析表明，Nhd1 的高表达主要调节了灌浆期碳水化合物和氨基酸的代谢。此外，Nhd1 的表达水平与一些地方主栽品种的籽粒 ECQ 呈正相关。因此，加强内源性 Nhd1 的丰度是提高稻米生产中籽粒 ECQ 的一种有前途的策略。
