Hong Di

Enhanced salinity tolerance in transgenic maize plants expressing a BADH gene from Atriplex micrantha

Salinity is an adverse environmental stress that limits the yield and quality of maize. As one of the most important osmolytes present in higher plants, glycinebetaine helps stabilize metabolism in plant cells and protects the constituents of cells from damage. In this study, a gene from Atriplex micrantha that encodes betaine aldehyde dehydrogenase was introduced by Agrobacterium-mediated transformation into maize inbred lines Zheng58 and Qi319 under the control of the maize ubiquitin promoter. Putative transgenic plants were confirmed by PCR and Southern blotting analysis. The transgenic maize plants expressed higher amounts of betaine aldehyde dehydrogenase activity and also grew better than the WT plants under NaCl stress. Compared with the wild type, the transgenic plants had increased fresh weight, lower malondialdehyde content, lower relative electrical conductivity, higher chlorophyll content, taller plant height, and higher grain yield under salt stress, which indicated that the expression of BADH gene in maize seedlings enhanced the salt tolerance of these plants.

Effect on Soil Properties of BcWRKY1 Transgenic Maize with Enhanced Salinity Tolerance

Maize (Zea mays L.) is the most important cereal crop in the world. However, soil salinity has become a major problem affecting plant productivity due to arable field degradation. Thus, transgenic maize transformed with a salinity tolerance gene has been developed to further evaluate its salt tolerance and effects on agronomic traits. It is necessary to analyze the potential environmental risk of transgenic maize before further commercialization. Enzyme activities, physicochemical properties, and microbial populations were evaluated in saline and nonsaline rhizosphere soils from a transgenic maize line (WL-73) overexpressing BcWRKY1 and from wild-type (WT) maize LH1037. Measurements were taken at four growth stages (V3, V9, R1, and R6) and repeated in three consecutive years (2012–2014). There was no change in the rhizosphere soils of either WL-73 or WT plants in the four soil enzyme activities, seven soil physicochemical properties, and the populations of three soil organisms. The results of this study suggested that salinity tolerant transgenic maize had no adverse impact on soil properties in soil rhizosphere during three consecutive years at two different locations and provided a theoretical basis for environmental impact monitoring of salinity tolerant transgenic maize.