Vol. 6, Issue 2, Part A (2024)

Quinoa (Chenopodium quinoa Willd.), an emerging climate-resilient pseudocereal, is notable for its exceptional tolerance to salinity, drought, cold, and heat, yet the transcriptomic mechanisms underlying its multi-stress resilience remain incompletely resolved. The present study aimed to generate integrative insights into the molecular basis of quinoa abiotic stress tolerance by comparing two contrasting ecotypes—Titicaca (salinity-tolerant) and Regalona (cold-adapted)—under salinity, drought, cold, and heat treatments. Plants were grown in controlled conditions, subjected to stress at the six-leaf stage, and sampled for physiological and transcriptomic analyses. RNA sequencing was performed on Illumina NovaSeq, followed by differential expression, gene ontology, and co-expression network analyses.
Physiological data revealed clear ecotype-dependent responses: Titicaca maintained higher relative water content (78% vs. 61%) and photosynthetic efficiency under salinity, higher stomatal conductance under drought, and reduced biomass loss under cold, whereas heat stress caused the strongest reproductive penalty, especially in Regalona. Transcriptomic profiling identified 12, 845 differentially expressed genes (DEGs) across stresses, including conserved modules enriched for abscisic acid (ABA) signaling, reactive oxygen species detoxification, ion transporters, and universal stress proteins. Stress-specific modules included ion homeostasis genes under salinity, aquaporins and osmolyte pathways under drought, alternative splicing factors under cold, and chaperone proteins under heat. Weighted gene co-expression network analysis (WGCNA) highlighted a 715-gene “core stress module” expressed across treatments, while principal component analysis (PCA) confirmed strong genotype × stress interactions. Epidermal bladder cell (EBC)-associated genes were significantly upregulated in Titicaca under salinity and drought but not universally across stresses, suggesting their role as conditional rather than universal determinants of tolerance.
Overall, these findings support the hypothesis that quinoa resilience emerges from a conserved stress backbone fine-tuned by ecotype-specific transcriptional regulation, with EBCs acting as auxiliary adaptations. Practical implications include the identification of transcriptomic biomarkers for marker-assisted selection, the necessity of ecotype-targeted breeding, and the integration of genetic and agronomic strategies to enhance quinoa productivity under climate variability.