*2.1. Characterization of PP2C Gene Family in Cotton*

The *Arabidopsis* 94 *PP2C* genes were obtained from TAIR (http://www.arabidopsis.org) with the help of Interpro scan domain (IPR001932) and then used as queries against *G. arboreum*, *G. barbadense*, *G. hirsutum*, and *G. raimondii* databases. This search resulted in 87, 147, 181, and 99 *PP2C* genes in *Gossypium* species i.e., *G. arboreum, G. barbadense, G. hirsutum,* and *G. Raimondii,* respectively. In the current study, we used the following nomenclature system for the *PP2C* genes to distinguish each PP2C from the homology of *Arabidopsis* and *Gossypium* species: GaPP2C (GaPP2C1–GaPP2C87) *G. arboreum*, GbPP2C (GbPP2C1–GbPP2C147) *G. barbadense*, GhPP2C (GhPP2C1–GhPP2C181) *G. hirsutum*, and GrPP2C (GrPP2C1–GrPP2C99) *G. raimondii*. We have studied different gene features of the *PP2C* genes including the chromosomal location, coding sequence length (CDS), protein length (aa), molecular weight (MW), isoelectric point (PI), grand average of hydropathicity (GRAVY), aliphatic index, and subcellular localization (Supplementary Tables S1–S4). In general, most of the PP2C proteins were in the range of 254–899 (GaPP2C1–GaPP2C66), 240–1630 (GbPP2C3–GbPP2C27), 263–794 (GhPP2C38–GhPP2C135), and 264–1101 (GrPP2C27–GrPP2C67) amino acids. The MWs of the proteins ranged from 27.99–100.38 (GaPP2C1–GaPP2C66), 26.45–181.58 (GbPP2C38–GbPP2C27), 28.65–100.47 (GhPP2C38–GhPP2C133), and 28.83–122.57 (GrPP2C27–GrPP2C1), the PIs ranged from 4.79–9.18 (GaPP2C28–GaPP2C7), 4.41–9.27 (GbPP2C96–GbPP2C135), 4.53–9.27 (GhPP2C57–GhPP2C177), and 4.64–9.27 (GrPP2C68–GrPP2C86), and the GRAVY ranged from −0.59–0.04 (GaPP2C66–GaPP2C64), −0.70–0.06 (GbPP2C27–GbPP2C102), −0.591–0.056 (GhPP2C132–GhPP2C127) and −0.587–0.071 (GrPP2C78–GrPP2C71). In our study, most of the *PP2C* genes showed hydrophilic properties with negative values, only a few of them were hydrophobic in nature with a positive value. The predicted subcellular localization results displayed that most of the PP2C proteins were confined in different organelles such as the chloroplast, the nuclear region, mitochondria, cytoplasm, and others (Supplementary Tables S1–S4).
