Enhancement of drought resistance and biomass by increasing the amount of glycine betaine in wheat seedlings

Abstract

Drought is a major agricultural menace reducing crop productivity and limiting the successful realization of land potential throughout the world. Therefore, breeding common wheat with improved drought-tolerance via genetic manipulation is of great importance. We have introduced the betA gene encoding choline dehydrogenase from Escherichia coli into common wheat (Triticum aestivum L.) by Agrobacterium-mediated transformation. Various levels of expression of the betA gene were confirmed by RT-PCR among the transgenic lines and different levels of glycine betaine accumulation were detected in these lines. Several wheat transgenic lines with different betA expression levels in the T3 generation and wild-type (WT) were selected to test their performance under drought stress conditions. Water deficit in plants caused a reduction in photosynthesis and activity of the PSII complex and resulted in increased accumulation of osmolytes. Drought stress also led to lower membrane stability along with much higher activities of superoxide dismutase and peroxidase in all wheat lines. However, wheat lines that were transgenic for the betA gene were less injured and exhibited greater root length and growth compared with the WT. It was concluded that the amount of injury to the wheat plants was negatively correlated with the level of accumulation of glycine betaine, and the glycine betaine acted as an important osmoprotectant in transgenic plants to improve root growth, and enhance the resistance of transgenic plants to drought stress.

Mitigating Effect of Glycinebetaine Pretreatment on Drought Stress Responses of Creeping Bentgrass

“…These results demonstrate that GB pretreatment can im-prove the activity of antioxidant enzymes, help prevent reactive oxygen species and oxidative damage, alleviate membrane lipid peroxidation, and thus maintain the integrity and function of cell membranes (DaCosta and Huang, 2007;Hussain Wani et al, 2013). It has been reported that these mitigations of GB pretreatment attributed to the wheat seedlings in the oxidation reaction under drought stress (He et al, 2011).…”

An insight into drought stress and signal transduction of abscisic acid

“…These were made drought resistant via over accumulation of GB, protection of photosynthetic machinery from damage caused by dehydration and accumulation of trehalose respectively (62,63,64).…”

Establishing an Efficient Way to Utilize the Drought Resistance Germplasm Population in Wheat

“…Developing high-yielding wheat cultivars under drought conditions in arid and semiarid regions is an important objective of breeding programs [5]. Although great efforts have been made in wheat drought resistance breeding, the decrease in agricultural productivity induced by drought stress still remains unsolved [8]. One reason is that the numerous germplasm resources were not effectively utilized in wheat breeding programs.…”