Department of Horticulture, International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, 528000, China.
Tasmanian Institute of Agriculture, University of Tasmania, Hobart, TAS, 7001, Australia.
Plant J. 2024 Jan;117(1):302-322. doi: 10.1111/tpj.16487. Epub 2023 Oct 5.
Understanding how nutrient stress impacts plant growth is fundamentally important to the development of approaches to improve crop production under nutrient limitation. Here we applied single-cell RNA sequencing to shoot apices of Pisum sativum grown under boron (B) deficiency. We identified up to 15 cell clusters based on the clustering of gene expression profiles and verified cell identity with cell-type-specific marker gene expression. Different cell types responded differently to B deficiency. Specifically, the expression of photosynthetic genes in mesophyll cells (MCs) was down-regulated by B deficiency, consistent with impaired photosynthetic rate. Furthermore, the down-regulation of stomatal development genes in guard cells, including homologs of MUTE and TOO MANY MOUTHS, correlated with a decrease in stomatal density under B deficiency. We also constructed the developmental trajectory of the shoot apical meristem (SAM) cells and a transcription factor interaction network. The developmental progression of SAM to MC was characterized by up-regulation of genes encoding histones and chromatin assembly and remodeling proteins including homologs of FASCIATA1 (FAS1) and SWITCH DEFECTIVE/SUCROSE NON-FERMENTABLE (SWI/SNF) complex. However, B deficiency suppressed their expression, which helps to explain impaired SAM development under B deficiency. These results represent a major advance over bulk-tissue RNA-seq analysis in which cell-type-specific responses are lost and hence important physiological responses to B deficiency are missed. The reported findings reveal strategies by which plants adapt to B deficiency thus offering breeders a set of specific targets for genetic improvement. The reported approach and resources have potential applications well beyond P. sativum species and could be applied to various legumes to improve their adaptability to multiple nutrient or abiotic stresses.
了解养分胁迫如何影响植物生长对于开发在养分限制下提高作物产量的方法至关重要。在这里，我们应用单细胞 RNA 测序分析了在硼（B）缺乏条件下生长的豌豆茎尖。我们根据基因表达谱的聚类确定了多达 15 个细胞簇，并通过细胞类型特异性标记基因表达验证了细胞身份。不同的细胞类型对 B 缺乏的反应不同。具体而言，B 缺乏导致叶肉细胞（MCs）中的光合作用基因表达下调，与光合速率受损一致。此外，保卫细胞中气孔发育基因的下调，包括 MUTE 和 TOO MANY MOUTHS 的同源物，与 B 缺乏下气孔密度的下降相关。我们还构建了茎尖分生组织（SAM）细胞的发育轨迹和转录因子相互作用网络。SAM 向 MC 的发育进展的特征是编码组蛋白和染色质组装和重塑蛋白的基因上调，包括 FASCIATA1（FAS1）和 SWITCH DEFECTIVE/SUCROSE NON-FERMENTABLE（SWI/SNF）复合物的同源物。然而，B 缺乏抑制了它们的表达，这有助于解释 B 缺乏下 SAM 发育受损。这些结果代表了对整体组织 RNA-seq 分析的重大进展，在整体组织 RNA-seq 分析中，细胞类型特异性反应丢失，因此错过了对 B 缺乏的重要生理反应。报告的发现揭示了植物适应 B 缺乏的策略，从而为培育者提供了一组用于遗传改良的特定目标。所报道的方法和资源具有超越豌豆物种的潜在应用，并且可以应用于各种豆科植物，以提高它们对多种养分或非生物胁迫的适应性。
