Molecular regulation and physiological functions of a novel FaHsfA2c cloned from tall fescue conferring plant tolerance to heat stress.

Heat stress transcription factors (HSFs) compose a large gene family, and different members play differential roles in regulating plant responses to abiotic stress. The objectives of this study were to identify and characterize an A2-type HSF, FaHsfA2c, in a cool-season perennial grass tall fescue (Festuca arundinacea Schreb.) for its association with heat tolerance and to determine the underlying physiological functions and regulatory mechanisms of FaHsfA2c imparting plant tolerance to heat stress. FaHsfA2c was localized in nucleus and exhibited a rapid transcriptional increase in leaves and roots during early phase of heat stress. Ectopic expression of FaHsfA2c improved basal and acquired thermotolerance in wild-type Arabidopsis and also restored heat-sensitive deficiency of hsfa2 mutant. Overexpression of FaHsfA2c in tall fescue enhanced plant tolerance to heat by triggering transcriptional regulation of heat-protective gene expression, improving photosynthetic capacity and maintaining plant growth under heat stress. Our results indicated that FaHsfA2c acted as a positive regulator conferring thermotolerance improvement in Arabidopsis and tall fescue, and it could be potentially used as a candidate gene for genetic modification and molecular breeding to develop heat-tolerant cool-season grass species.

Transcriptional regulation of heat shock proteins and ascorbate peroxidase by CtHsfA2b from African bermudagrass conferring heat tolerance in Arabidopsis.

Heat stress transcription factor A2s (HsfA2s) are key regulators in plant response to high temperature. Our objectives were to isolate an HsfA2 gene (CtHsfA2b) from a warm-season grass species, African bermudagrass (Cynodon transvaalensis Burtt-Davy), and to determine the physiological functions and transcriptional regulation of HsfA2 for improving heat tolerance. Gene expression analysis revealed that CtHsfA2b was heat-inducible and exhibited rapid response to increasing temperature. Ectopic expression of CtHsfA2b improved heat tolerance in Arabidopsis and restored heat-sensitive defects of Arabidopsis hsfa2 mutant, which was demonstrated by higher survival rate and photosynthetic parameters, and lower electrolyte leakage in transgenic plants compared to the WT or hsfa2 mutant. CtHsfA2b transgenic plants showed elevated transcriptional regulation of several downstream genes, including those encoding ascorbate peroxidase (AtApx2) and heat shock proteins [AtHsp18.1-CI, AtHsp22.0-ER, AtHsp25.3-P and AtHsp26.5-P(r), AtHsp70b and AtHsp101-3]. CtHsfA2b was found to bind to the heat shock element (HSE) on the promoter of AtApx2 and enhanced transcriptional activity of AtApx2. These results suggested that CtHsfA2b could play positive roles in heat protection by up-regulating antioxidant defense and chaperoning mechanisms. CtHsfA2b has the potential to be used as a candidate gene to genetically modify cool-season species for improving heat tolerance.

Reconstruction of Complex Facial Defects Using Cervical Expanded Flap Prefabricated by Temporoparietal Fascia Flap.

UNLABELLED: Reconstruction of complex facial defects using cervical expanded flap prefabricated by temporoparietal fascia flap. BACKGROUND: Complex facial defects are required to restore not only function but also aesthetic appearance, so it is vital challenge for plastic surgeons. Skin grafts and traditional flap transfer cannot meet the reconstructive requirements of color and texture with recipient. The purpose of this sturdy is to create an expanded prefabricated temporoparietal fascia flap to repair complex facial defects. METHODS: Two patients suffered severe burns on the face underwent complex facial resurfacing with prefabricated cervical flap. The vasculature of prefabricated flap, including the superficial temporal vessel and surrounding fascia, was used as the vascular carrier. The temporoparietal fascia flap was sutured underneath the cervical subcutaneous tissue, and expansion was begun in postoperative 1 week. After 4 to 6 months of expansion, the expander was removed, facial scars were excised, and cervical prefabricated flap was elevated and transferred to repair the complex facial defects. RESULTS: Two complex facial defects were repaired successfully by prefabricated temporoparietal fascia flap, and prefabricated flaps survived completely. On account of donor site's skin was thinner and expanded too fast, 1 expanded skin flap was rupture during expansion, but necrosis was not occurred after the 2nd operation. Venous congestion was observed in 1 patient, but after dressing, flap necrosis was not happened. Donor site was closed primarily. Postoperative follow-up 6 months, the color, texture of prefabricated flap was well-matched with facial skin. CONCLUSION: This method of expanded prefabricated flap may provide a reliable solution to the complex facial resurfacing.

[Reconstruction of facial defects with frontal expanded flaps bipedicled by superficial temple vessels and supraorbital/supratrochlear neurovascular bundles].

OBJECTIVE: To investigate the therapeutic effect of reconstruction of facial defects with frontal expanded flaps bipedicled by superficial temple vessels and supraorbital/supratrochlear neurovascular bundles. METHODS: From June 2006 to Mar. 2013, the patients with mostly unilateral facial defects which affected temple area and crossed the facial midline, were treated with frontal expanded flaps. The expanders were implanted at first stage and the expanded frontal flaps were transferred at second stage. At third stage, pedicle division was performed and the pedicle skin tissue was used to repair the residue defect. RESULT: All the 18 flaps survived completely with satisfactory color and texture. Good results were achieved during the follow-up period of one year. CONCLUSION: The bipedicled frontal expanded flap has a reliable blood supply which is very suitable for large facial defect.