A Method for Rapid and Reliable Molecular Detection of Drought-Response Genes in Sorghum bicolor (L.) Moench Roots

Drought is a major environmental stress that limits growth and productivity in agricultural ecosystems limiting crop yield worldwide. Breeding crops for enhanced drought tolerance is a priority to preserve food security on the increasing world population. Recent work in Arabidopsis has shown that vascular brassinosteroid receptor BRL3 (Brassinosteroid insensitive like-3) transcriptionally controls the production of osmoprotectant metabolites that confer drought resistance without penalizing growth, offering new and exciting possibilities for biotechnological improvement of drought-resistant crops. In cereals, understanding transcriptional responses to drought is an essential step for the production of gene-edited drought-resistant cereals. In this chapter, we present a method to analyze the transcriptional responses to drought in Sorghum bicolor (L.) Moench, our cereal of choice. Among the genes we tested, we found that drought marker gene SbDHN1 has a 1000-fold increase only after 1 day of drought, bringing possibilities for the development of molecular sensors for testing drought. Overall, this analysis is useful to set up conditions of high-throughput transcriptomic analysis of drought stressed plants before drought phenotype is observed.