Plants 2022, 11, 2877. https://doi.org/10.3390/plants11212877 www.mdpi.com/journal/plants Review Crop Proteomics under Abiotic Stress: From Data to Insights Rehana Kausar 1 , Xin Wang 2 and Setsuko Komatsu 3, * 1 Department of Botany, University of Azad Jammu and Kashmir, Muzaffarabad 13100, Pakistan 2 College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China 3 Faculty of Environment and Information Sciences, Fukui University of Technology, Fukui 910-8505, Japan * Correspondence: skomatsu@fukui-ut.ac.jp; Tel.: +81-766-29-2466 Abstract: Food security is a major challenge in the present world due to erratic weather and climatic changes. Environmental stress negatively affects plant growth and development which leads to re- duced crop yields. Technological advancements have caused remarkable improvements in crop- breeding programs. Proteins have an indispensable role in developing stress resilience and toler- ance in crops. Genomic and biotechnological advancements have made the process of crop improve- ment more accurate and targeted. Proteomic studies provide the information required for such tar- geted approaches. The crosstalk among cellular components is being analyzed by subcellular pro- teomics. Additionally, the functional diversity of proteins is being unraveled by post-translational modifications during abiotic stress. The exploration of precise cellular responses and the network- ing among different cellular organelles help in the prediction of signaling pathways and protein– protein interactions. High-throughput mass-spectrometry-based protein studies are now possible due to incremental advancements in mass-spectrometry techniques, sample protocols, and bioin- formatic tools as well as the increasing availability of plant genome sequence information for mul- tiple species. In this review, the key role of proteomic analysis in identifying the abiotic-stress-re- sponsive mechanisms in various crops was summarized. The development and availability of ad- vanced computational tools were discussed in detail. The highly variable protein responses among different crops have provided a wide avenue for molecular-marker-assisted genetic buildup studies to develop smart, high-yielding, and stress-tolerant varieties to cope with food-security challenges. Keywords: proteomics; crop; abiotic stress 1. Introduction Abiotic stresses include drought, salt, temperature, waterlogging, and nutritional de- ficiency/excess, all of which hamper plant growth and seed yield to a great extent. During waterlogging, all or almost all of the plants are covered with water and face unfavorable conditions such as low light intensity, restricted gas diffusion, and the effusion of soil nutrients [1]. Plant-growth-promoting rhizobacteria encode 1-aminocyclopropane-1-car- boxylate (ACC) deaminase which cleaves the substrate of ACC to produce ketobutyrate and ammonia to mitigate the adverse effects of waterlogging [2]. According to forecasts, half of all crop loss is attributable to abiotic stresses. However, abiotic stresses cause a myriad of changes in the physiological, molecular, and biochemical processes operating in plants [3]. These stressors greatly limit the distribution of plants, alter growth/develop- ment patterns, and reduce seed yield [4]. Studying drought and its potential impacts on food security is crucial in a global context [5]. Drought induces oxidative stress through the overproduction of reactive-oxygen species (ROS), ultimately causing the cell mem- brane to rupture and stimulating various stress-signaling pathways, including ROS, mi- togen-activated protein kinase, Ca 2+ , and hormone-mediated signaling. The key responses against drought stress are root development, stomatal closure, photosynthesis, hormone production, and ROS scavenging [6]. Sustainable genetic improvements could be Citation: Kausar, R.; Wang, X.; Komatsu, S. Crop Proteomics under Abiotic Stress: From Data to Insights. Plants 2022, 11, 2877. https://doi.org/10.3390/ plants11212877 Academic Editors: Pavel Kerchev and Abdelali Hannoufa Received: 11 September 2022 Accepted: 22 October 2022 Published: 27 October 2022 Publisher’s Note: MDPI stays neu- tral with regard to jurisdictional claims in published maps and institu- tional affiliations. Copyright: © 2022 by the authors. Li- censee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and con- ditions of the Creative Commons At- tribution (CC BY) license (https://cre- ativecommons.org/licenses/by/4.0/).