Expression Patterns of Drought-related miRNAs in Chickpea (Cicer arietinum L.) under Drought Stress

DROUGHT is a prominent abiotic stress that has a global impact on crop yields. MicroRNAs have been shown to be significant modulators of plant drought tolerance. The impact of drought stress on three chickpea varieties (Giza 1, Giza 2, and Giza 3) and the expression profiles of miRNA genes were evaluated at various levels of polyethylene glycol (PEG) (0, 10%, 20%, and 30%). Increased PEG levels reduced germination percentage, root and shoot length, relative water content (RWC%), and photosynthetic pigments. The highest PEG level (30%) resulted in a significant decrease in germination percent, root, and shoot lengths. The largest reduction in germination percentage and root length was detected in Giza 2, whereas Giza 3 exhibited the highest germination percentage and root length. In addition, the highest RWC% was detected in Giza 3, whereas the lowest was recorded in Giza 2. These results suggest that Giza 3 is the most drought-resilient, whereas Giza 2 is the most drought-sensitive. The expression profiles of five microRNA (miRNA) genes in Giza 2 and Giza 3 revealed that at high drought stress (30% PEG), five miRNA genes were significantly reduced in both the roots and shoots of Giza 2, except miR408b, which was increased by 1.17-fold in the Giza 2 shoots. In contrast, they showed a significantly higher fold-change in both the roots and shoots of Giza 3, except for miR104, which was down-regulated in the roots of Giza 3. These findings suggest that up-regulated miRNA genes play a significant role in the drought tolerance of the chickpea Giza 3 variety.