TRANSCRIPTOMIC ANALYSIS OF ADAPTIVE RESPONSES TO NITROGEN DEFICIENCY IN QUINOA

Abstract

Quinoa (Chenopodium quinoa) is a promising pseudocereal crop that grows well under nutrient-poor conditions. To elucidate the transcriptional changes and the associated alterations in physiological parameters in response to low nitrogen (LN) and nitrogen starvation (NS) conditions, we identified differentially expressed genes (DEGs) in LN and NS seedlings compared with CK seedlings and investigated related photosynthetic parameters changes and biomass accumulation. Compared with CK seedlings, 2404 and 4362 DEGs at day 5, and 10,466 and 11,107 at day 30 were identified, respectively. DECs related to antioxidant biosynthesis were up-regulated after 5 days of LN or NS treatment, and DEGs related to carbon metabolism were up-regulated after 30 days. Five genes related to Psb and ten genes related to Rubisco were highly expressed which contributed to the improved biomass under low-nitrogen conditions. Five out of the seven CA genes involved in nitrogen metabolism were strongly induced. After 30 days, the photosynthetic parameters in LN and NS treatment were decreased compared with those in the CK, and the LN treatment had a smaller effect on photosynthetic parameters than the NS treatment. After 120 days, quinoa in LN treatment group showed higher NUE than the CK, in which the grain yield and nitrogen concentration were 67.4% and 58.2% of those in the CK, respectively, with 20% nitrogen application of the CK. These results provide insight into the molecular and physiological mechanisms associated with the low-nitrogen adaptations of quinoa, which could be useful for breeding crop cultivars that tolerate nitrogen deficiency.