Expression of a DREB 5-A subgroup transcription factor gene from Ricinus communis (RcDREB1) enhanced growth, drought tolerance and pollen viability in tobacco

Abstract

Climate change has increased the frequency of long periods of drought, affecting crop cultivation worldwide. Losses due to water stress exceed ten percent of world production of major crops, reaching three-quarters of production areas, with severe economic losses. Therefore, the generation of environmental stress-tolerant genotypes that are more e cient in water use is extremely important. We have previously isolated and characterized a DREB transcription factor coding gene, named RcDREB1, from castor bean (Ricinus communis L.), which probably belongs to the CBF/DREB subfamily subgroup A-5. Aiming to develop drought-tolerant lines, we have stably introduced and expressed the RcDREB1 transgene into tobacco. Transgenic lines have revealed an enhanced drought tolerance. Genetically modi ed lines cultivated under water de cit presented a higher photosynthetic rate, stomatal conductance, leaf water potential and leaf water content when compared to the control. Transgenic lines revealed lower transpiration rates. In addition, biometric analyses showed that transgenic lines cultivated under water stress presented higher biomass, higher fresh and dry weight and higher plant height than the non-transgenic lines. After re-watering, transgenic lines recovered faster than non-transgenic plants.Moreover, pollen grains from transgenic plants revealed a remarkable increase in viability after exposure to heat (38 ºC) and desiccation stresses. The results presented here will be the foundation for production of commercial crops that are more tolerant to environmental stresses and long-life pollen grains, increasing pollination and in consequence, productivity.

Seed Priming with Chitosan Improves Germination Characteristics Associated with Alterations in Antioxidant Defense and Dehydration-Responsive Pathway in White Clover under Water Stress

“…DREBs regulate stress-defensive genes expression by binding to the DRE/C-repeat core component of these downstream genes under different abiotic stresses [ 44 ]. It has been found that transgenic tobacco overexpressing an RcDREB 5-A showed better growth and higher biomass than non-transgenic lines in response to drought stress [ 45 ]. Similarly, up-regulation of PcDREB2A could significantly improve drought tolerance of Arabidopsis [ 46 ].…”

Transcriptome Profiles Reveals ScDREB10 from Syntrichia caninervis Regulated Phenylpropanoid Biosynthesis and Starch/Sucrose Metabolism to Enhance Plant Stress Tolerance

“…While the functions of the A-1 and A-2 subgroups have been extensively explored [ 14 ], the roles and underlying mechanisms of A-5-type DREB genes have garnered limited attention and remain relatively enigmatic, despite their promising potential. In recent years, of the majority of studies have reported that A-5 DREB transcription factors can significantly enhance stress tolerance in plants [ 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Collectively, these investigations highlighted the potential of A-5 DREB genes as promising candidates for crop breeding programs aimed at enhancing stress tolerance.…”

Dynamic QTL mapping revealed primarily the genetic structure of photosynthetic traits in castor (Ricinus communis L.)

“…A little was reported on photosynthetic traits in castor. Previous studies have reported that photosynthetic O 2 -evolution and 14 CO 2 -fixation rates in blades decreased with increasing nuclear genome duplication 25 ; Photosynthesis in capsule wall promotes fuller seed filling 26 , and that in seed coat increases lipid accumulation 27 , seedling growth 28 and seed development 29 ; In response to stresses such as high temperature, drought, flooding and high salinity, castor plants reduce water loss by decreasing stomatal conductance to prevent irreversible leaf wilting and further develop mechanisms to adapt to the environment 30 – 34 ; RcDREB1 , a pollen-specific and desiccation-associated transcription factor gene from castor, enhanced the drought tolerance (lower Tr), photosynthetic rate, biomass and pollen grain viability of transgenic tobacco 35 . The information concerning the genetic mechanism of photosynthetic traits is a serious shortage in castor.…”