Wood Formation under Severe Drought Invokes Adjustment of the Hormonal and Transcriptional Landscape in Poplar.
Dade YuDennis JanzKrzysztof ZienkiewiczCornelia HerrfurthIvo Doe FeussnerShaoliang ChenAndrea PollePublished in: International journal of molecular sciences (2021)
Drought is a severe environmental stress that exerts negative effects on plant growth. In trees, drought leads to reduced secondary growth and altered wood anatomy. The mechanisms underlying wood stress adaptation are not well understood. Here, we investigated the physiological, anatomical, hormonal, and transcriptional responses of poplar to strong drought. Drought-stressed xylem was characterized by higher vessel frequencies, smaller vessel lumina, and thicker secondary fiber cell walls. These changes were accompanied by strong increases in abscisic acid (ABA) and antagonistic changes in salicylic acid in wood. Transcriptional evidence supported ABA biosynthesis and signaling in wood. Since ABA signaling activates the fiber-thickening factor NST1, we expected upregulation of the secondary cell wall (SCW) cascade under stress. By contrast, transcription factors and biosynthesis genes for SCW formation were down-regulated, whereas a small set of cellulose synthase-like genes and a huge array of genes involved in cell wall modification were up-regulated in drought-stressed wood. Therefore, we suggest that ABA signaling monitors normal SCW biosynthesis and that drought causes a switch from normal to "stress wood" formation recruiting a dedicated set of genes for cell wall biosynthesis and remodeling. This proposition implies that drought-induced changes in cell wall properties underlie regulatory mechanisms distinct from those of normal wood.
Keyphrases
- cell wall
- arabidopsis thaliana
- transcription factor
- plant growth
- heat stress
- climate change
- genome wide identification
- gene expression
- heat shock
- genome wide
- type diabetes
- cell proliferation
- signaling pathway
- magnetic resonance
- computed tomography
- stress induced
- early onset
- mesenchymal stem cells
- adipose tissue
- magnetic resonance imaging
- human health
- ionic liquid
- high throughput
- mass spectrometry
- contrast enhanced
- heat shock protein