Molecular mechanism of leaf adaxial upward curling caused by BpPIN3 suppression in Betula pendula.

Leaves are one of the vegetative organs of plants that are essential for plant growth and development. PIN-FORMED (PINs) gene is an indoleacetic acid (IAA) transporter that plays a critical role in leaf development. To determine the function of BpPIN3 in leaf polarity formation in Betula pendula, the transgenic lines with BpPIN3 overexpression (OE) and BpPIN3-reduced expression (RE) were analyzed using the Agrobacterium-mediated method. The RE lines displayed the characteristics of leaf margin adaxial upward curling, with lower expression of BpPIN3 resulting in greater rolling. Tissue localization of IAA in the auxin GUS reporter system proved that auxin in the RE was mainly distributed in the secondary veins, palisade tissues, and epidermal cells in the leaf margin area. The auxin content in the leaf margin area was significantly greater than that in the main vein tissue. The cell density of the palisade tissue and the ratio of palisade tissue to spongy tissue in the curled leaf margin of the RE lines were found to be significantly decreased. RNA-seq analysis revealed that the RE hormone-signaling pathway genes were significantly enriched compared with those of the OE and WT lines; in particular, the auxin response-related genes SAURs (i.e., SAUR23, SAUR24, SAUR28, and SAUR50) and GH3.10 were found to be significantly upregulated. qRT-PCR analysis indicated that BpPIN3 expression at the leaf margin was significantly lower than that near the main vein in the RE lines. In contrast, the expression levels of SAURs and GH3.10 were significantly higher than those near the midrib. In conclusion, BpPIN3 regulates the expression of auxin response-related genes and the polar transport of auxin to change the polar form of the proximal and distal axes of birch leaves.

Role of PsnWRKY70 in Regulatory Network Response to Infection with Alternaria alternata (Fr.) Keissl in Populus.

WRKY is an important complex family of transcription factors involved in plant immune responses. Among them, WRKY70 plays an important role in the process of the plant defense response to the invasion of pathogens. However, the defense mechanism of PsnWRKY70 is not clear in Populus nigra. In this study, we showed that PsnWRKY70-overexpression lines (OE) had fewer leaf blight symptoms than PsnWRKY70-repressing lines (RE). PsnWRKY70 activated MAP kinase cascade genes (PsnM2K4, PsnMPK3, PsnM3K18), calcium channel proteins-related genes (PsnCNG3, PsnCNGC1, PsnCNG4), and calcium-dependent protein kinases genes (PsnCDPKL, PsnCDPKW, PsnCDPKS, PsnCDPKQ). Furthermore, 129 genes of PsnWRKY70 putative genome-wide direct targets (DTGs) were identified by using transcriptome (RNA-seq) and DNA affinity purification sequencing (DAP-seq). PsnWRKY70 directly binds to the promoters of homologous genes and LRR domain proteins to promote the expression of WRKY6, WRKY18, WRKY22, and WRKY22-1, LRR domain proteins LRR8, LRR-RLK, ADR1-like 2, NB-ARC, etc. Our study suggests that PsnWRKY70 enhances the resistance of A. alternata in poplar by activating genes in both pathogen-associated molecular pattern-triggered immunity (PTI) and effector-triggered immunity (ETI).

[Outcome of surgery for interrupted aortic arch combined cardiac anomaly].

OBJECTIVE: To retrospectively review the experience in repair of interrupted aortic arch (IAA) and associated cardiac anomaly. METHODS: From January 1997 to January 2008, 36 patients with interrupted aortic arch and associated cardiac anomaly underwent surgical treatment. There were 22 male and 14 female. Mean age of the 35 children patients was 2.8 years, with a range from 2 months to 7 years. There was a 31 years old adult patient. Types of interrupted aortic arch include 30 cases of type A and 6 cases of type B. In all 36 patients, 33 cases had patent ductus arteriosus (PDA) and intracardiac abnormality, including 28 cases of simple anomaly as ventricular septal defect and 5 cases of complex anomaly, two cases were single IAA arch without PDA and other cardiac defect, one case had no intracardiac anomaly but PDA. For 33 patients with PDA and intracardiac anomaly, median sternotomy was used to simultaneously repair interrupted aortic arch and intracardiac defect in 31 cases, left thoracotomy and median sternotomy were applied to repair IAA and intracardiac anomaly respectively in one case, one patient had palliative repair. For three patients without intracardiac anomaly, left thoracotomy was applied in two cases, median sternotomy and abdominotomy were used in one adult patient. Techniques of operation for interrupted aortic arch include 16 cases of conduit connection, 9 cases of direct anastomosis, 9 cases of direct anastomosis with patch augmentation, 1 case of subclavian flap aortoplasty. In all 31 cases of one-stage operation through median sternotomy, selective cerebral perfusion was used in 17 patients, deep hypothermia and low flow were applied in 8 cases, deep hypothermia circulatory arrest was performed in 6 patients. RESULTS: There were 5 hospital deaths. Three cases died of pulmonary infection, 1 case died of of pulmonary hypertension crisis, and another case died of postoperative low cardiac output, which was misdiagnosed before operation. Seven cases had other main postoperative complications. Thirty-one survivors were followed up from 3 months to 5 years, there was no late death and reoperation. CONCLUSION: One-stage repair through median sternotomy using selective cerebral perfusion or deep hypothermia and low flow can be applied to most of the cases with associated cardiac anomaly.

[Surgical treatment of aortic coarctation with intracardiac anomaly in infants and toddlers].

OBJECTIVE: To review the experience in repair of aortic coarctation with intracardiac anomaly in infants and toddlers. METHODS: From January 2000 to December 2006, 84 infants and children diagnosed as aortic coarctation with intracardiac anomaly underwent surgical treatment. Mean age of the patients was 13.5 months, with a range from 1 month to 3 years. Mean body weight was 7.3 kg, with a range from 3.3 to 15 kg. Twelve patients complicated with complex intracardiac anomaly. Seventy-two patients complicated with ventricular septal defect and other simple anomaly. Twenty-one patients had hypoplasia of the aortic arch. Sixty-two patients had one-stage repair. Median sternotomy was used to simultaneously repair coarctation and intracardiac defect in 49 patients. Left thoracotomy and median sternotomy were applied to repair aortic coarctation and intracardiac anomaly respectively in 13 patients. Twenty-two patients had staged repair. Operational techniques for aortic coarctation include 42 patients of patch aortoplasty, 30 patients of resection and end-to-end anastomosis, 6 patients of subclavian flap aortoplasty, 3 patients of vascular bypass, and 1 patient of balloon dilation. In all 49 patients of one-stage operation through median sternotomy, selective cerebral perfusion was used in 43 patients, deep hypothermia low flow was applied in 4 patients, deep hypothermia circulatory arrest was performed in 2 patients. RESULTS: There were 8 hospital deaths. The mortality is 9.5%. Among 8 deaths, 3 patients were misdiagnosed. CONCLUSIONS: Surgeries for aortic coarctation with intracardiac anomaly have satisfactory short-term results in infants and toddlers. One-stage repair through median sternotomy can be applied to most of the patients. Selective cerebral perfusion with deep hypothermia and circulatory arrest in lower body can protect the brain and other vital organs.

[Radionuclide pulmonary perfusion imaging in evaluating pulmonary hypertension in patients with rheumatic heart disease].

OBJECTIVE: To evaluate the degree of pulmonary hypertension in patients with rheumatic heart disease using radionuclide pulmonary perfusion imaging. METHODS: The pulmonary perfusion in 25 patients with rheumatic heart disease was examined using scintigram with macroaggregates of (99m)Tc-labeled human serum albumin (PPS) before and 7 days after operation. PPS was analyzed for (1) pulmonary perfusion steady time (PT), right upper and lower lung count ratio (RULR). The results were compared with those of catheterization examination during the operation. RESULTS: The pulmonary arterial systolic pressure (PAs) and total pulmonary resistance (TPR) were (60 +/- 21) mm Hg and (421 +/- 106) dyn if PT > or = 20 seconds and RULR > or = 2; The PAs and TPR were (28 +/- 5) mm Hg and (188 +/- 28) dyn if PT < 20 seconds and RULR < 2. The PPS changed in most of the patients during early operation. CONCLUSION: The degree of injury in pulmonary vascular in patients with rheumatic heart disease could be quantitatively analysed by PPS.