Overexpression of the late embryonic genesis abundant protein MGL3 improves the drought tolerance of maize (Zea mays L.)

Abstract

With the increasing severity of climate change, drought has become a global issue that seriously restricts the development and production of crops. Maize (Zea mays L.) is one of the major food crops in the world. Therefore, the demand for drought-tolerant maize varieties has been rapidly increasing in the market. Recent studies have found that late embryogenesis abundant (LEA) proteins are involved in plant responses to various osmotic stresses such as drought and salt stress. Thus, we hypothesized that LEA genes may provide similar stress tolerance abilities in maize. We isolated ZmMGL3 of the LEA gene family and developed transgenic maize plants overexpressing ZmMGL3 using Agrobacterium-mediated transformation. Then, we conducted physiological and biochemical evaluations of the transgenic maize plants exposed to drought stress. Under drought stress (10% polyethylene glycol 6000), the transgenic maize plants showed improved germination rate, seed vigor, radicle length, root length at the seedling stage, and wilting degree after drought and rewatering compared to the wild-type plants. The transgenic plants also accumulated more catalase, superoxide dismutase, peroxidase, hydrogen peroxide, and superoxide radicals compared to the wild-type plants. These results indicate that ZmMGL3 enhances drought resistance in maize plants by reducing the content of reactive oxygen species in the leaves and can be used as a candidate gene for the development of drought-tolerant maize varieties.