In planta study on the role of soybean cytokinin dehydrogenase to plant reproductive traints under drought stress condition

Abstract

Cytokinins (CKs) are important phytohormones that govern plant development and growth as well as help plants adapt to drought stress. During plant development, including the blooming and seed production stages, CKs play a vital role in controlling the dynamics of organ source/sink connections. Therefore, CKs are important factors in seed yield. The CK oxidases/dehydrogenases (CKXs) is one of the essential enzymes in charge of controlling the levels of CK in plants. Changes in CKX activity are strongly linked with seed yield in many crop species, including soybean (Glycine max L.). However, the roles of members within the CKX gene family in soybean have not yet been investigated. Furthermore, CKs have been known to participate in regulating plant responses to drought stress and previously, GmCKX13 has been identified as a drought-responsive gene. Therefore, the purpose of this study was to characterize the importance of this gene in promoting soybean drought tolerance during reproductive stages by analyzing yield-related parameters. In order to manage the water stress, plants were grown under normal condition over the course of vegetative stage and irrigation were stopped at two different phases during reproductive stage: beginning of flowering (R1) and beginning of pod formation (R3). According to the obtained analyses, a water shortage occurring at the beginning of the pod filling resulted in a more severe loss in productivity, due to the substantial decrease in both average seed weight and seed yield. While drought treatment at beginning of the flowering stage (R1) markedly decreased the number of flowers, fruits, and seeds, but only slightly affected the seed weight. In addition, the findings revealed a positive role of GmCKX13 under drought condition, as its overexpression could improve the plants' ability to adapt to water deprivation conditions and minimize yield loss. Our data support the potential use of GmCKX13 in genetic engineering to enhance the plants' stress tolerance to drought