Variation Analysis of Physiological Traits in Betula platyphylla Overexpressing TaLEA-ThbZIP Gene under Salt Stress

Abstract

The aim of this study was to determine whether transgenic birch (Betula platyphylla) ectopic overexpressing a late embryogenesis abundant (LEA) gene and a basic leucine zipper (bZIP) gene from the salt-tolerant genus Tamarix (salt cedar) show increased tolerance to salt (NaCl) stress. Co-transfer of TaLEA and ThbZIP in birch under the control of two independent CaMV 35S promoters significantly enhanced salt stress. PCR and northern blot analyses indicated that the two genes were ectopically overexpressed in several dual-gene transgenic birch lines. We compared the effects of salt stress among three transgenic birch lines (L-4, L-5, and L-8) and wild type (WT). In all lines, the net photosynthesis values were higher before salt stress treatment than afterwards. After the salt stress treatment, the transgenic lines L-4 and L-8 showed higher values for photosynthetic traits, chlorophyll fluorescence, peroxidase and superoxide dismutase activities, and lower malondialdehyde and Na+ contents, compared with those in WT and L-5. These different responses to salt stress suggested that the transcriptional level of the TaLEA and ThbZIP genes differed among the transgenic lines, resulting in a variety of genetic and phenotypic effects. The results of this research can provide a theoretical basis for the genetic engineering of salt-tolerant trees.

Research progress on genetic improvement of Betula platyphylla Suk.

“…Increasing the number of primers, however, improved the ability to distinguish genetic differences between different provenances. With 15 pairs of SRAP primers, the percentage of detectable polymorphic loci was above 98.5% [55] . Of 583 B. platyphylla trees, 100 were selected after measuring the length of individual fibers.…”

“…The heterogenous Tamarix TaLEA-ThbZIP gene was transferred into B. platyphylla and nine transgenic lines showing drought resistance and salt tolerance were obtained, including five transgenic lines containing LEA genes which could grow normally in soil containing 0.5% NaCl and four transgenic lines expressing bZIP genes. The results indicated that these transgenic lines had improved drought resistance and salt tolerance [55] .…”

Gene Coexpression Network Analysis Indicates that Hub Genes Related to Photosynthesis and Starch Synthesis Modulate Salt Stress Tolerance in Ulmus pumila

“…Abiotic stress tolerance is a complex quantitative trait, and significant differences have been observed in stress resistance among species, or even genotypes of the same species [ 32 , 33 , 34 ]. Survival rates of five U. pumila cultivars pointed to significantly different levels of salt tolerance, implying that these cultivars might be suitable for afforestation of soils with different salinity levels.…”

High-Temperature-Responsive Poplar lncRNAs Modulate Target Gene Expression via RNA Interference and Act as RNA Scaffolds to Enhance Heat Tolerance

“…Chlorophyll fluorescence images were obtained using the Chlorophyll Fluorescence System (Heinz-Walz Instruments, Effeltrich, Germany) according to the manufacturer's instructions. Malondialdehyde (MDA), peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX) activities were measured by absorption photometry using a spectrophotometer, according to the method described by Song et al [61,62].…”