Given that soil salinity significantly limits plant growth and production in agricultural land, research on salt stress is of particular agricultural relevance. In this study, for the purposes of functional screening of genes involved in salt stress responses, we selected approximately 651 transgenic Arabidopsis lines (157 independent full-length) from a transgenic Arabidopsis population overexpressing full-length Brassica rapa cDNAs. Initial screening indicated that the transgenic lines of 12 genes showed apparent salt tolerance phenotypes when exposed to NaCl at a concentration of 125 mM, among which, two genes (BrATL30 and BrZHD10) were selected for detailed characterization. The T₃ progeny of these transgenic lines exhibited accelerated seed germination, often accompanied by faster root growth and higher survival rate, compared with wild-type plants under salt stress. Additionally, in order to examine the agricultural potential of the two selected B. rapa genes, we constructed BrATL30- and BrZHD10-overexpressing Brassica napus transgenic plants (BrATL30-OX and BrZHD10-OX), which showed apparent high salt stress-tolerant phenotypes compared with wild-type plants. Furthermore, we found that the basal expression of several salt- and abiotic stress-responsive genes was higher in transgenic plants than in wild-type plants. Taken together, this study will provide two valuable functional genes related to salt stress tolerance.

AbstractThe SHORT VEGETATIVE PHASE (SVP) gene encodes a MADS-box gene family of transcription factors that repress floral transition. To explore the function of the Brassica rapa SVP (BrSVP) gene during the flowering time of this species, a construct containing BrSVP under the control of the cauliflower mosaic virus 35S promoter was introduced into B. rapa via Agrobacterium-mediated transformation. The resulting transgenic plants showed delayed flowering time, and RT-PCR analyses further revealed that BrSVP repressed the expression of the floral integrator genes AGL20, AGL24, and FT during vernalization. Our data indicated that BrSVP acts as a negative regulator in the flowering time of B. rapa and that it may therefore be a useful genetic source for crop improvement with respect to flowering time regulation.

Maize is the most important grain crop in the world. Genetic engineering technology has been used to enhance its various agronomical traits. The transformation of maize is a crucial step in the application of gene technologies to improve maize. The choice of genotype and explant material influences the transformation efficiency and the production of stable transgenic plants. Immature embryos of Hi IIA were infected with Agrobacterium tumefaciens LBA4404 including superbinary vectors (bar and GUS or GFP genes). The transformation efficiency was based on transgenic calli induction from immature embryos on the selection medium with 3 mg/L bialaphos. The transformation efficiency varied from 1.01 to 2.74%. The integration and expression of bar, GUS, and GFP genes were confirmed in T₀ and T₁ generations of transgenic plants using genomic PCR and the bar strip test. In addition, herbicide resistance in T₁ transgenic plants was observed when leaves and whole plants were treated with Basta. These results suggest that the successful Agrobacterium-mediated transformation of Hi IIA will improve further opportunities for functional genomic and genome editing studies in maize.

GROWTH-REGULATING FACTOR (GRF) genes encode plant-specific transcription factors and play critical roles in regulating the growth and development of lateral organs. In order to explore the agricultural potential of Brassica rapa GRF genes (BrGRFs), we constructed two BrGRF-overexpressing B. napus plants (BrGRF3-1OX and -9OX). BrGRF3-1OX and -9OX developed larger cotyledons, leaves, and seeds than the wild type. The increased organs’ sizes were due to increases in cell number, but not due to cell size alterations. RT-PCR analysis revealed that BrGRFs regulated the expression of a wide range of genes that are involved in gibberellin-, auxin-, cell division-related growth processes. Taken together, our data indicate that BrGRFs act as positive regulators of B. napus growth, thus raising the possibility that they may serve as a useful genetic source for crop improvement with respect to organ size and seed production.