Thirty years of genetic progress combined with seed ethylene priming improved drought resistance of wheat through long-term drought stress memory

Abstract

Knowledge of short-term physiological adaption of wheat to soil water deficit is well understood, but little is known about seed ethylene priming effect on long-term drought stress memory of dryland winter wheat. The 42 leading and new cultivars released between 1992 to 2017 were subjected to drought (45% Field water-holding capacity), and well-watered (75% Field water-holding capacity) conditions aim to screen cultivars with contrasting drought resistance and grain yield. Seeds primed with ethylene were subjected to both PEG-8000 and pure water to uncover ethylene-induced stress memory at both physiological and organ levels. Results showed that the soil water deficit (45%FC) that occurred at the tillering stage resulted in 3.2% to 67.4% yield loss for 42 cultivars, which was determined mainly by the decrease in the fertile spike. Seed ethylene priming maintained leaf water by reducing root volume and dry weight, which played a crucial role in drought avoidance. Seed ethylene priming decreased malondialdehyde content by regulating auxin and abscisic acid signaling, reactive oxygen species scavenging capability, and osmotic regulation, which plays a crucial role in drought tolerance. Seed ethylene priming improved drought tolerance of the wheat through metabolic modification of carbon metabolism, glutathione metabolism, and phenylpropanoid biosynthesis . The seed ethylene priming induced long-term stress memory that improved tillering capacity and reduced wheat spikelets abortion, which provided extra 0.3 t ha -1 of grain yield. These results suggested that seed ethylene priming allowed the recall of long-lasting stress defensive memory, increasing grain yield by both drought avoidance and drought tolerance.

Silver nanoparticles protect tillering in drought-stressed wheat by improving leaf water relations and physiological functioning

“…Drought at tillering might disturb the hormones regulating tillering pathway, roots functioning and leaf physiological process (Bacher et al 2022;Yang et al 2022). Abid et al (2016) and Yang et al (2021) investigated the effects of drought stress on wheat tillering and found that moderate drought stress results in a reduction of the number of tillers per plant, while severe drought stress causes a significant reduction in both tiller number and size. The unaffected wheat tillers under mild drought imply that wheat plants tend to conserve moisture rather than using maximum field capacity.…”