Nutrient accumulation and transcriptome patterns during grain development in rice

Rice is an important source of calories and mineral nutrients for more than half of the world's population. The accumulation of essential and toxic mineral elements in rice grain affects its nutritional quality and safety. However, the patterns and processes by which different elements progressively accumulate during grain filling remain largely unknown. In the present study, we investigated temporal changes in dry matter, elemental concentrations, and the transcriptome in the grain of field-grown rice. We also investigated the effects of seed setting rate and the position of the grain within the rice panicle on element accumulation. Three different patterns of accumulation were observed: (i) elements including K, Mn, B, and Ca showed an early accumulation pattern; (ii) dry matter and elements including N, P, S, Mg, Cu, Zn, Mo, As, and Cd showed a mid accumulation pattern; and (iii) elements such as Fe showed a gradual increase pattern. These different accumulation patterns can be explained by the differences in the biogeochemical behavior of the various elements in the soil, as well as differences in plant nutrient redistribution, gene expression, and the sink-source relationship. These results improve our knowledge of the dynamics of elemental accumulation in rice grain and are helpful for identification of functional genes mediating the translocation of elements to grain. Mineral nutrients accumulated in rice grains in three distinct patterns during grain development, with corresponding patterns of gene expression based on transcriptomic analysis. Different nutrients displayed different spatial distribution patterns in the grain.

Automated summary

Rice is a vital source of calories and mineral nutrients, but the accumulation of essential and toxic elements in rice grain remains poorly understood. This study analyzed the temporal changes in dry matter, elemental concentrations, and gene expression during grain development. Three distinct patterns of element accumulation were observed, which can be attributed to differences in soil behavior, nutrient redistribution, gene expression, and sink-source relationship.