Candidate-gene expression patterns in diploid and tetraploid Lolium multiflorum spp. multiflorum cultivars under water deficit

Drought is a critical abiotic stress that disrupts redox homeostasis and is detrimental to plant development. To respond to drought, plants have developed complex mechanisms that allow them to perceive and counter abiotic stresses rapidly. Polyploidy gives rise to many gene expression changes allowing plants to adapt to a broader ecological range. The present study was designed to compare the expression of drought-related genes in diploid cultivars and induced tetraploid lines of Westerwolths ryegrass (Lolium multiflorum ssp. multiflorum). Plants were grown for three weeks in the growth chambers and were subjected to 5 days of water deficit. The relative expression of candidate genes was checked at three-time points, and the relative water content (RWC) was also calculated. The results of the experiment showed critical differences in response to water deficit periods between the diploid cultivars and their respective induced tetraploid lines. The induced tetraploid lines showed a significantly higher expression of drought-related genes than their diploid parents and had higher RWC. Also, out of the genes investigated, dehydrin is the most responsive gene to water deficit periods in Westerwolths ryegrass. Understanding the differential expression pattern of genes involved in drought response provides insight into how cytotypes respond to water deficit periods.