Variability in drought gene expression datasets highlight the need for community standardization.

Physiologically relevant drought stress is difficult to apply consistently, and the heterogeneity in experimental design, growth conditions, and sampling schemes make it challenging to compare water deficit studies in plants. Here, we re-analyzed hundreds of drought gene expression experiments across diverse model and crop species and quantified the variability across studies. We found that drought studies are surprisingly uncomparable, even when accounting for differences in genotype, environment, drought severity, and method of drying. Many studies, including most Arabidopsis work, lack high-quality phenotypic and physiological datasets to accompany gene expression, making it impossible to assess the severity or in some cases the occurrence of water deficit stress events. From these datasets, we developed supervised learning classifiers that can accurately predict if RNA-seq samples have experienced a physiologically relevant drought stress, and suggest this can be used as a quality control for future studies. Together, our analyses highlight the need for more community standardization, and the importance of paired physiology data to quantify stress severity for reproducibility and future data analyses.

Leveraging millets for developing climate resilient agriculture.

C4 grasses dominate natural and agricultural settings, and the widespread success of wild grasses is mostly attributable to their resilience to environmental extremes. Much of this natural stress tolerance has been lost in major cereals as a byproduct of domestication and intensive selection. Millets are an exception, and they were domesticated in semi-arid regions of Sub-Saharan Africa and Asia where selection favored tolerance and stability over yield. Here, we review the evolutionary and domestication histories of millets and the traits that enable their stress tolerance, broad adaptability, and superior nutritional qualities compared to other cereals. We discuss genome editing and advanced breeding approaches that can be used to develop nutritious, climate resilient cereals of the future. Finally, we propose that millets can play a central role in the global food system to combat food insecurity, with researchers and germplasm from the Global South at the center of these efforts.