Abstract
Drought is one of the most important abiotic stresses that seriously affects cotton growth, development, and production worldwide. However, the molecular mechanism, key pathway, and responsible genes for drought tolerance incotton have not been stated clearly. In this research, high-throughput next generation sequencing technique was utilized to investigate gene expression profiles of three cotton species (Gossypium hirsutum, Gossypium arboreum, and Gossypium barbadense L.) under drought stress. A total of 6968 differentially expressed genes (DEGs) were identified, where 2053, 742, and 4173 genes were tested as statistically significant; 648, 320, and 1998 genes were up-regulated, and 1405, 422, and 2175 were down-regulated in TM-1, Zhongmian-16, and Pima4-S, respectively. Total DEGs were annotated and classified into functional groups under gene ontology analysis. The biological process was present only in tolerant species(TM-1), indicating drought tolerance condition. The Kyoto encyclopedia of genes and genomes showed the involvement of plant hormone signal transduction and metabolic pathways enrichment under drought stress. Several transcription factors associated with ethylene-responsive genes (ICE1, MYB44, FAMA, etc.) were identified as playing key roles in acclimatizing to drought stress. Drought also caused significant changes in the expression of certain functional genes linked to abscisic acid (ABA) responses (NCED, PYL, PP2C, and SRK2E), reactive oxygen species (ROS) related in small heat shock protein and 18.1 kDa I heat shock protein, YLS3, and ODORANT1 genes. These results will provide deeper insights into the molecular mechanisms of drought stress adaptation in cotton.
Highlights
Drought is one of the major abiotic stresses that greatly affects plant growth and crop production worldwide
Drought-responsive molecular mechanisms were examined in three cotton species (TM-1, Zhongmian-16, and Pima4-S) to identify potential candidate genes involved in drought tolerance, through deep RNA sequencing of Gossypium spp seedlings subjected to drought was performed using Illumina sequencing platform
We found MYB44 transcriptome factor which interacts with the abscisic acid (ABA) receptor proteins like PYLs, which bind to phosphatase 2C (PP2C), suggesting that MYB44 is directly involved in ABA signaling in TM-1 cotton species [82,83]
Summary
Drought is one of the major abiotic stresses that greatly affects plant growth and crop production worldwide. It inhibits metabolism, development, and growth of many crops [1,2]. Plants maintain turgor and persist metabolism in cells even at low water potential, mainly by synthesis of osmolytes or/and compatible solutes [3]. Thousands of genes and many signaling pathways have been identified in plants during drought stress [2,5,6]. Under drought avoidance and tolerance mechanisms, plants maintain high water status during stress by reducing transpirationand/or improving water absorption, sustaining turgor, and maintaining a steady metabolism rate even at low water potential [7]
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