Screening of drought tolerant germplasm of sorghum during germination Study on drought tolerance mechanism

Drought stress during emergence is an important abiotic stress during sorghum growth, and drought severely affects seedling emergence and high-yielding population establishment. In order to investigate the mechanisms of drought tolerance in sorghum during germination, this study analysed physiological changes and transcriptomic data of two sorghum lines, W069 (drought tolerant) and W040 (drought sensitive). Under drought stress, phenotypic analysis showed thatW069 had longer shoot and root lengths compared to W040. Analysis of the physiological data showed that W069 had a higher osmotic substance content, however, it had a lower MDA content. In order to further analyse the differentially expressed genes associated with drought tolerance in sorghum, In the Kyoto Encyclopedia of Genes and Genome (KEGG) analyses, we focused on three major pathways (i.e. starch and sucrose metabolism, phenylpropanoid biosynthesis and phytohormone signalling) involved in the response to drought stress during seed germination, and elucidated the roles of these three pathways in drought germination in sorghum. Taken together, these findings deepen our understanding of drought-responsive gene networks during seed germination in sorghum. They provide potential target genes and strategies for genetic improvement of drought tolerance in this crop.