Abstract
BackgroundNumerous regulatory genes participate in plant thermotolerance. In Arabidopsis, HEAT-INDUCED TAS1 TARGET2 (HTT2) is an important thermotolerance gene that is silenced by ta-siR255, a trans-acting siRNA. ta-siR255 is absent from heading Chinese cabbage (Brassica rapa ssp. pekinensis). Our previous attempt to overexpress the endogenous BrpHTT2 gene of heading Chinese cabbage (B. rapa ssp. pekinensis) failed because of cosuppression. In theory, heading Chinese cabbage can overexpress Arabidopsis HTT2 to improve thermotolerance in the absence of ta-siR255-mediated gene silencing and the weak potential of coexpression.ResultsTo test the potential application of HTT2 in improving crop thermotolerance, we transferred p35S::HTT2 to heading Chinese cabbage. We tested the leaf electrical conductivity, hypocotyl elongation, and survival percentage of p35S::HTT2 plants subjected to high-temperature (38 °C) and heat-shock (46 °C) treatment. The leaf electrical conductivity of p35S::HTT2 seedlings under high temperature decreased but did negligibly change under heat shock. The hypocotyl length of p35S::HTT2 seedlings increased under high temperature and heat shock. The survival rate of p35S::HTT2 seedlings increased under heat shock. BrpHsfs, a subset of heat-shock factor genes, were upregulated in p35S::HTT2 plants under high-temperature and heat shock conditions. In the field, transgenic plants with HTT2 appeared greener and formed leafy heads earlier than wild-type plants.ConclusionsExogenous HTT2 increased the survival rates of heat-shocked heading Chinese cabbage by promoting thermotolerance through decreasing electrical conductivity and extending hypocotyl length. Our work provides a new approach to the genetic manipulation of thermotolerance in crops through the introduction of exogenous thermotolerance genes.
Highlights
Numerous regulatory genes participate in plant thermotolerance
The absence of BrpMIR173, BrpTAS1, and siR255 from B. rapa indicates that B. rapa lacks the siR255 biogenesis system
The expression levels of HTT1 and HEAT-INDUCED TAS1 TARGET2 (HTT2) are drastically up-regulated in A. thaliana seedlings in response to heat shock, whereas the expression of TAS1a is inhibited by heat [9]
Summary
Numerous regulatory genes participate in plant thermotolerance. In Arabidopsis, HEAT-INDUCED TAS1 TARGET2 (HTT2) is an important thermotolerance gene that is silenced by ta-siR255, a trans-acting siRNA. ta-siR255 is absent from heading Chinese cabbage (Brassica rapa ssp. pekinensis). Ta-siR255 is absent from heading Chinese cabbage Our previous attempt to overexpress the endogenous BrpHTT2 gene of heading Chinese cabbage In theory, heading Chinese cabbage can overexpress Arabidopsis HTT2 to improve thermotolerance in the absence of ta-siR255-mediated gene silencing and the weak potential of coexpression. Crop growth and yield are seriously affected by abiotic stresses, such as heat, cold, drought, waterlogging, and salinity. Among these stresses, high-temperature stress associated with global warming is one of the major threats that may result in extensive losses in global agriculture. In recent years, numerous researchers have attempted to improve the thermotolerance of crops to decrease yield losses and to ensure global food security. Increasing the heat resistance of B. rapa is vital for agriculture production
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
