MicroRNA-guided regulation of drought stress response in bread wheat
Sequencing of 4 small RNA libraries produced 201M raw reads were obtained from the corresponding 4 PARE libraries. From these, we identified 156 known and 57 novel microRNAs from heat tolerant wheat genotype NI5439 and heat susceptible wheat genotype WL711 under drought stress condition. We identified 156 known and 57 novel microRNAs from NI5439 and WL711 wheat genotype under DS condition. Family distribution analysis showed the identified miRNA belongs to more than 18 different families in which the-miR9662a.3p was the most abundant. The most prominent length of miRNA was 21 nts regulating drought stress. We identified 2300 targets for the known miRNAs reported in wheat. Pathways analysis of the identified targets showed most of the target genes were involved in signal transduction, transport, organelle localization, DNA methylation, histone modification, chromatin modification, and plant development. Overall design: Two contrasting wheat genotypes were grown under well-watered and severe drought conditions. The two selected genotypes were sown in PVC pipe columns. The well-watered treatment plants were kept at normal condition while the drought treated plants were placed in the transparent sheet covered area. Initially, three germinated seeds were sown in each pipe and later only one healthy seedling per pipe was retained at 15 days after sowing. The pipe was irrigated twice daily to maintain the soil moisture before the start of progressive soil drying. Drought stress was initiated at Z24 Zadok s scale and root tissues were taken at Zadoks scale (Z37 flag leaf stage) and frozen immediately in liquid nitrogen in triplicates and these 4 total RNA pooled samples were used to construct sRNA libraries.