State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Int J Mol Sci. 2022 May 31;23(11):6203. doi: 10.3390/ijms23116203.
Sulfur (S) is an essential mineral nutrient required for plant growth and development. Plants usually face temporal and spatial variation in sulfur availability, including the heterogeneous sulfate content in soils. As sessile organisms, plants have evolved sophisticated mechanisms to modify their gene expression and physiological processes in order to optimize S acquisition and usage. Such plasticity relies on a complicated network to locally sense S availability and systemically respond to S status, which remains poorly understood. Here, we took advantage of a split-root system and performed transcriptome-wide gene expression analysis on rice plants in S deficiency followed by sulfate resupply. S deficiency altered the expressions of 6749 and 1589 genes in roots and shoots, respectively, accounting for 18.07% and 4.28% of total transcripts detected. Homogeneous sulfate resupply in both split-root halves recovered the expression of 27.06% of S-deficiency-responsive genes in shoots, while 20.76% of S-deficiency-responsive genes were recovered by heterogeneous sulfate resupply with only one split-root half being resupplied with sulfate. The local sulfate resupply response genes with expressions only recovered in the split-root half resupplied with sulfate but not in the other half remained in S deficiency were identified in roots, which were mainly enriched in cellular amino acid metabolic process and root growth and development. Several systemic response genes were also identified in roots, whose expressions remained unchanged in the split-root half resupplied with sulfate but were recovered in the other split-root half without sulfate resupply. The systemic response genes were mainly related to calcium signaling and auxin and ABA signaling. In addition, a large number of S-deficiency-responsive genes exhibited simultaneous local and systemic responses to sulfate resupply, such as the sulfate transporter gene and the gene, highlighting the existence of a systemic regulation of sulfate uptake and assimilation in S deficiency plants followed by sulfate resupply. Our studies provided a comprehensive transcriptome-wide picture of a local and systemic response to heterogeneous sulfate resupply, which will facilitate an understanding of the systemic regulation of S homeostasis in rice.
硫（S）是植物生长和发育所必需的一种重要的矿物质营养元素。植物通常面临着硫供应的时空变化，包括土壤中不均匀的硫酸盐含量。作为固着生物，植物已经进化出了复杂的机制来改变它们的基因表达和生理过程，以优化 S 的获取和利用。这种可塑性依赖于一个复杂的网络来局部感知 S 的可用性，并对 S 状态做出系统响应，但目前对此知之甚少。在这里，我们利用分根系统，对 S 缺乏后再供应硫酸盐的水稻植株进行了全转录组基因表达分析。S 缺乏分别改变了根系和地上部 6749 和 1589 个基因的表达，分别占检测到的总转录本的 18.07%和 4.28%。在两个分根半体中均匀供应硫酸盐恢复了地上部 S 缺乏响应基因的 27.06%的表达，而只有一个分根半体供应硫酸盐时，通过不均匀供应硫酸盐恢复了 20.76%的 S 缺乏响应基因的表达。在 S 缺乏时，仅在供应硫酸盐的分根半体中恢复表达的局部硫酸盐供应响应基因，而在另一半分根中仍保持 S 缺乏状态，这些基因主要富集在细胞氨基酸代谢过程和根的生长发育中。在根中还鉴定到了一些系统响应基因，它们在供应硫酸盐的分根半体中的表达保持不变，但在没有硫酸盐供应的另一个分根半体中恢复。系统响应基因主要与钙信号和生长素和 ABA 信号有关。此外，大量的 S 缺乏响应基因对硫酸盐供应表现出局部和系统的同时响应，如硫酸盐转运基因 和 基因，这突出了在 S 缺乏植物中硫酸盐摄取和同化的系统调节在硫酸盐供应后的存在。我们的研究提供了一个对不均匀硫酸盐供应的局部和系统响应的全转录组范围的图片，这将有助于理解水稻中 S 稳态的系统调节。
