D'Hooghe Philippe, Kopriva Stanislav, Avice Jean-Christophe, Trouverie Jacques
Normandie Université, UNICAEN, INRAe, UMR 950 Ecophysiologie Végétale, Agronomie & nutritions NCS, SFR Normandie Végétal (FED4277), 14032 Caen CEDEX 05, France.
Institute for Plant Sciences and Cluster of Excellence on Plant Sciences (CEPLAS), University of Cologne, Cologne, Germany.
J Exp Bot. 2025 May 27;76(8):2278-2296. doi: 10.1093/jxb/eraf028.
The response of oilseed rape to sulfur (S) restriction usually consists of increasing the components of S utilization efficiency (absorption, assimilation, and remobilization) to provide S to seeds. However, source-sink relationships and S management in developing seeds under sulfate restriction are poorly understood. To address this, impacts of sulfate restrictions applied at 'visible bud' or 'start of pod filling' stages were studied in two genotypes, Aviso and Capitol. The two cultivars have similar seed yield, but Capitol has higher seed weight and lower number of seeds per plant under non-limited conditions. S flow at the whole-plant level (using [34S]sulfate labelling) and S metabolism changes [S-compounds, and ATP sulfurylase and adenosine 5'-phosphosulfate reductase (APR) activities] were studied during seed development. Seed yield, protein quality, and accumulation of S metabolites were affected by sulfate restriction less and later in Aviso than in Capitol. This was related to higher S uptake and stronger remobilization of S from vegetative organs to seeds during early seed development in response to sulfate restriction. A higher seed APR activity was observed for Capitol in response to sulfate limitation, suggesting that APR is not limiting for sulfate assimilation and that seed S metabolism is principally devoted to S-amino acids and protein synthesis.
油菜对硫（S）限制的响应通常包括提高硫利用效率的各个组成部分（吸收、同化和再转运），以便为种子提供硫。然而，在硫酸盐限制条件下发育种子中的源库关系和硫管理却鲜为人知。为了解决这个问题，研究了在“可见芽期”或“荚果充实开始期”施加硫酸盐限制对两个基因型品种Aviso和Capitol的影响。这两个品种的种子产量相似，但在非限制条件下，Capitol的种子重量更高，单株种子数量更少。在种子发育过程中，研究了全株水平的硫流（使用[34S]硫酸盐标记）以及硫代谢变化（硫化合物、ATP硫酸化酶和腺苷5'-磷酸硫酸还原酶（APR）活性）。与Capitol相比，Aviso受硫酸盐限制对种子产量、蛋白质质量和硫代谢物积累的影响较小且较晚。这与在种子发育早期，Aviso响应硫酸盐限制从营养器官向种子的硫吸收更高和硫再转运更强有关。在硫酸盐限制条件下，Capitol种子的APR活性更高，这表明APR对硫酸盐同化没有限制作用，并且种子硫代谢主要致力于硫氨基酸和蛋白质的合成。
