The Effect of Overexpression of Two Brassica CBF/DREB1-like Transcription Factors on Photosynthetic Capacity and Freezing Tolerance in Brassica napus

Abstract

The effects of overexpression of two Brassica CBF/DREB1-like transcription factors (BNCBF5 and 17) in Brassica napus cv. Westar were studied. In addition to developing constitutive freezing tolerance and constitutively accumulating COR gene mRNAs, BNCBF5- and 17-overexpressing plants also accumulate moderate transcript levels of genes involved in photosynthesis and chloroplast development as identified by microarray and Northern analyses. These include GLK1- and GLK2-like transcription factors involved in chloroplast photosynthetic development, chloroplast stroma cyclophilin ROC4 (AtCYP20-3), beta-amylase and triose-P/Pi translocator. In parallel with these changes, increases in photosynthetic efficiency and capacity, pigment pool sizes, increased capacities of the Calvin cycle enzymes, and enzymes of starch and sucrose biosynthesis, as well as glycolysis and oxaloacetate/malate exchange are seen, suggesting that BNCBF overexpression has partially mimicked cold-induced photosynthetic acclimation constitutively. Taken together, these results suggest that BNCBF/DREB1 overexpression in Brassica not only resulted in increased constitutive freezing tolerance but also partially regulated chloroplast development to increase photochemical efficiency and photosynthetic capacity.

Gene expression changes in response to drought stress in Ilex paraguariensis leaves

“…The expression of GLK-1 in I. paraguariensis stressed leaves was induced 3-to 7-fold, depending on the severity of dehydration (Table 1). Savitch et al (2005) have reported that cold stress and cold acclimation of Brassica napus plants is associated with a moderate accumulation of mRNA for GLK-1 and GLK-2. Similarly, the amino acid composition is modified by environmental conditions and characterized by the elevated accumulation of specific amino acids involved in plant stress tolerance (Planchet and Limami, 2015).…”

Morphological traits and genetic diversity of differently overwintered oilseed rape (Brassica napus L.) cultivars

“…As a result, growers' major concern is good cold tolerance and yield. When biennial plants find themselves in low, non-freezing temperatures -they acclimate to cold undergoing genetic, morphological and physiological changes and therefore gaining freezing tolerance (Savitch et al, 2005). Low temperatures are very important for plant growth and survival, during autumn period plants acclimate and achieve better frost tolerance (Anurag et al, 2004).…”

“…When plants are long-term cold acclimated, some morphological changes occur -they become dwarf, their leaves get thicker because of increased mesophyll cell size, specific leaf weight, decrease of leaf water content, etc. (Savitch et al, 2005). Therefore low temperatures have an important influence on the survival of plants and can change the peculiarities of plant growth and productivity -these changes occur due to the changes in gene expression (Kurbidaeva, Novokreshchenova, 2011;Lee, Tomashow, 2012).…”

The Role of Dreb Transcription Factors in Abiotic Stress Tolerance of Plants

“…transgenic plants showed high root/shoot ratio that resulted in 20-30% more water uptake under dehydration condition. expression of several cBF-type genes in transgenic canola resulted in freezing tolerance and high photosynthetic activity (55). transgenic chrysanthemum with expression of AtDREB1A showed drought and salt tolerance and accumulated higher proline content and SoD activity (23).…”