Laboratory of Plant Molecular Genetics and Biotechnology, Federal University of Rio de Janeiro, Biology Institute, Dept. of Genetics, Av. Carlos Chagas Filho, 373 - Ilha do Fundão, 21941-902, Rio de Janeiro, RJ, Brazil.
Laboratory of Plant Molecular Genetics and Biotechnology, Federal University of Rio de Janeiro, Biology Institute, Dept. of Genetics, Av. Carlos Chagas Filho, 373 - Ilha do Fundão, 21941-902, Rio de Janeiro, RJ, Brazil.
Plant Physiol Biochem. 2021 Dec;169:211-223. doi: 10.1016/j.plaphy.2021.11.015. Epub 2021 Nov 13.
Water deficits are responsible for countless agricultural losses. Among the affected crops, C4 plants are of special interest due to their high water and nitrogen use efficiency. Two accessions of Setaria viridis (Ast-1 and A10.1) with contrasting responses to water deficit were used in the current work to better understand the mechanisms behind drought tolerance in C4 species. Our results showed that although the A10.1 accession exhibited a reduced size and lower Rfd values in comparison to Ast-1, it had overall higher Fv/Fm and lower NPQ values in well-watered conditions. The water deficit induction was performed with PEG-8000 at the grain-filling stage using dehydration cycles. Analysis of physiological measurements showed the A10.1 accession as being more tolerant to multiple water deficit exposures. In addition, PCA identified a clear difference in the pattern of drought response of the accessions. Four drought marker genes previously described in the literature were chosen to evaluate the response at the molecular level: SvP5CS2, SvDHN1, SvNAC6, and SvWRKY1. Besides confirming that Ast-1 is a more sensitive accession, the expression analysis revealed that SvNAC1 might better monitor drought stress, while SvWRKY1 was able to differentiate the two accessions. Distinct evolutionary histories of each accession may be behind their differences in response to water deficits.
水分亏缺是造成无数农业损失的原因。在受影响的作物中，C4 植物因其高水和氮利用效率而受到特别关注。本研究使用了两个具有不同水分亏缺响应的柳枝稷品系（Ast-1 和 A10.1），以更好地理解 C4 物种耐旱性背后的机制。我们的结果表明，尽管 A10.1 品系的大小和 Rfd 值比 Ast-1 降低，但在水分充足的条件下，它的 Fv/Fm 值总体上更高，NPQ 值更低。在灌浆期，使用脱水循环，用 PEG-8000 诱导水分亏缺。生理测量分析表明，A10.1 品系对多次水分亏缺暴露更具耐受性。此外，PCA 确定了品系对干旱响应模式的明显差异。选择了文献中描述的四个先前的干旱标记基因来评估分子水平的响应：SvP5CS2、SvDHN1、SvNAC6 和 SvWRKY1。除了证实 Ast-1 是一个更敏感的品系外，表达分析表明 SvNAC1 可能更好地监测干旱胁迫，而 SvWRKY1 能够区分两个品系。每个品系独特的进化历史可能是它们对水分亏缺响应差异的原因。
