**5. Conclusions**

This study identified sixteen (16) SAMS genes in upland cotton and comprehensively explored their chromosomal locations, gene structure, phylogenetic relationships, cis-acting elements, conserved motifs, and expression under drought and salt stress conditions. We found that *GhSAMS* genes might be primarily involved in the network's regulation of various environmental stresses. Particularly, *GhSAMS2* was identified as a promising candidate gene for the targeted improvement of upland cotton's tolerance to multiple abiotic stresses. The downregulation of *GhSAMS2* expression via VIGS confirmed its pivotal role in mediating the plant's response to abiotic stress. Our findings provide reference information for the in-depth investigation of *GhSAMS* genes' functions and for dissecting the complex molecular networks associated with abiotic stress tolerance in cotton.

**Supplementary Materials:** The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/agronomy13020612/s1, Additional file 1, Table S1: SAMS genes from other plant species analyzed in this study; Table S2: List of primers used for the RT-qPCR analysis; Table S3: List of primers used in Y2H experiments; Table S4: Cis-regulatory elements detected within the promoter region of *GhSAMS* genes. Additional file 2, Figure S1: Heat maps showing *GhSAMS* genes' differential expression in *G. hirsutum* under drought and salt stress conditions; Figure S2: Self-auto-activation state, toxicity test, verification of interactions, and mating efficiency determination of the *GhCBL10* bait gene in a Yeast Two-Hybrid system; Figure S3: Phenotypic observation of cotton seedlings under VIGS and *GhSAMS2* expression analysis via RT-qPCR; Figure S4: Morphology of VIGS and wild type plants under the conditions of drought and salt stress.

**Author Contributions:** Conceptualization, methodology, and validation, J.W.K., T.G.M., Y.W. (Yangyang Wei), Y.X. and F.L.; formal analysis, data curation, and writing—original draft preparation, M.J.U., R.O.M., M.L.S., J.N.K. and R.P.; writing—review and editing, Y.H., Y.W. (Yuhong Wang), X.C. and J.W.K.; supervision, F.L. and Z.Z.; project administration and funding acquisition, F.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the National Natural Science Foundation of China (32171994, 32072023) and the National Key R&D Program of China ((2021YFE0101200), PSF/CRP/18th Protocol (07).

**Informed Consent Statement:** Informed consent was obtained from all subjects involved in this study.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
