Transcriptomic and physiological shade avoidance responses in potato (Solanum tuberosum) plants

Area of Science:

• Plant biology
• Plant physiology
• Agricultural science

Background:

• Plants perceive shade through changes in photosynthetically active radiation (PAR) and the red:far-red (R:FR) light ratio.
• Light signals are detected by photoreceptors, initiating shade avoidance responses like stem elongation.
• These responses can increase susceptibility to pathogens.

Purpose of the Study:

• To investigate the morphological, anatomical, and photosynthetic responses of potato plants to simulated shade.
• To analyze gene expression changes under shade conditions.
• To assess the impact of shade on potato plant susceptibility to fungal pathogens.

Main Methods:

• Potato plants (Solanum tuberosum var. Spunta) were grown under sunlight or simulated shade.
• Morphological and anatomical measurements were taken.
• Photosynthesis rates were measured.
• RNA-seq and quantitative reverse transcription polymerase chain reaction (qRT-PCR) were used for gene expression analysis.
• Fungal infection assays were performed.

Main Results:

• Simulated shade induced stem and internode elongation, increased free auxin in stems, and reduced tuber production.
• Shaded plants had thinner upper leaf mesophyll and wider epidermis.
• Photosynthesis rates differed in upper and basal leaves under shade.
• Shade altered the expression of genes including FLOWERING LOCUS T (FT), WRKY-like, PAR1b, and FLAVONOL 4-SULFOTRANSFERASE.
• Shaded plants showed increased susceptibility to Botrytis cinerea.

Conclusions:

• Simulated shade significantly alters potato plant growth, physiology, and defense mechanisms.
• Shade induces a shift towards vegetative growth (elongation) at the expense of tuber production.
• Potato plants grown in shade are more vulnerable to necrotrophic fungal pathogens.