Jilin Da'an Agro-ecosystem National Observation Research Station, Changchun Jingyuetan Remote Sensing Experiment Station, Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
State Key Laboratory of Cotton Biology, Henan Joint International Laboratory for Crop Multi-Omics Research, School of Life Sciences, Henan University, No. 85 Jinming Road, Kaifeng 475004, China.
Plant Physiol. 2022 Nov 28;190(4):2671-2687. doi: 10.1093/plphys/kiac336.
The karrikin (KAR) receptor and several related signaling components have been identified by forward genetic screening, but only a few studies have reported on upstream and downstream KAR signaling components and their roles in drought tolerance. Here, we characterized the functions of KAR UPREGULATED F-BOX 1 (KUF1) in drought tolerance using a reverse genetics approach in Arabidopsis (Arabidopsis thaliana). We observed that kuf1 mutant plants were more tolerant to drought stress than wild-type (WT) plants. To clarify the mechanisms by which KUF1 negatively regulates drought tolerance, we performed physiological, transcriptome, and morphological analyses. We found that kuf1 plants limited leaf water loss by reducing stomatal aperture and cuticular permeability. In addition, kuf1 plants showed increased sensitivity of stomatal closure, seed germination, primary root growth, and leaf senescence to abscisic acid (ABA). Genome-wide transcriptome comparisons of kuf1 and WT rosette leaves before and after dehydration showed that the differences in various drought tolerance-related traits were accompanied by differences in the expression of genes associated with stomatal closure (e.g. OPEN STOMATA 1), lipid and fatty acid metabolism (e.g. WAX ESTER SYNTHASE), and ABA responsiveness (e.g. ABA-RESPONSIVE ELEMENT 3). The kuf1 mutant plants had higher root/shoot ratios and root hair densities than WT plants, suggesting that they could absorb more water than WT plants. Together, these results demonstrate that KUF1 negatively regulates drought tolerance by modulating various physiological traits, morphological adjustments, and ABA responses and that the genetic manipulation of KUF1 in crops is a potential means of enhancing their drought tolerance.
通过正向遗传学筛选已经鉴定出了卡瑞林（KAR）受体和几个相关的信号转导成分，但仅有少数研究报道了 KAR 信号转导的上游和下游成分及其在耐旱性中的作用。在这里，我们采用反向遗传学方法在拟南芥（Arabidopsis thaliana）中对 KAR 上调 F-BOX 1（KUF1）在耐旱性中的功能进行了表征。我们观察到，kuf1 突变体植物比野生型（WT）植物更能耐受干旱胁迫。为了阐明 KUF1 负调控耐旱性的机制，我们进行了生理学、转录组和形态学分析。我们发现，kuf1 植物通过减少气孔开度和角质层渗透率来限制叶片水分损失。此外，kuf1 植物对脱落酸（ABA）诱导的气孔关闭、种子萌发、主根生长和叶片衰老表现出更高的敏感性。kuf1 和 WT 莲座叶在脱水前后的全基因组转录组比较表明，各种耐旱性相关性状的差异伴随着与气孔关闭（如 OPEN STOMATA 1）、脂质和脂肪酸代谢（如 WAX ESTER SYNTHASE）以及 ABA 响应（如 ABA-RESPONSIVE ELEMENT 3）相关的基因表达差异。kuf1 突变体植物的根/茎比和根毛密度高于 WT 植物，这表明它们比 WT 植物能吸收更多的水分。综上所述，这些结果表明，KUF1 通过调节各种生理特性、形态调整和 ABA 响应来负调控耐旱性，并且在作物中对 KUF1 的遗传操作是增强其耐旱性的一种潜在手段。
