PubMed · 2026-02-15
Warmer nights caused by climate change reduce rice grain quality by throwing off the balance between protein and starch. A study of two rice varieties found that one accumulated excess protein under high nighttime temperatures, making the rice stickier, chalkier, and less palatable.
Nighttime temperatures raised from 22°C to 27°C significantly increased grain protein content in one rice variety (YY4949) but not the other (HHZ), demonstrating clear genetic differences in heat stress response.
The protein-to-amylose ratio showed a stronger correlation with chalkiness and pasting (cooking texture) characteristics than protein content alone, identifying it as a key quality indicator under heat stress.
Accelerated chloroplast breakdown and upregulated nitrogen transport enzymes in YY4949 drove excessive nitrogen remobilization from leaves to grains, depleting the leaf 'source' and disrupting starch-protein balance in the grain.
