Wheat photosystem II heat tolerance: evidence for genotype-by-environment interactions.

High temperature stress inhibits photosynthesis and threatens wheat production. One measure of photosynthetic heat tolerance is Tcrit - the critical temperature at which incipient damage to photosystem II (PSII) occurs. This trait could be improved in wheat by exploiting genetic variation and genotype-by-environment interactions (GEI). Flag leaf Tcrit of 54 wheat genotypes was evaluated in 12 thermal environments over 3 years in Australia, and analysed using linear mixed models to assess GEI effects. Nine of the 12 environments had significant genetic effects and highly variable broad-sense heritability (H2 ranged from 0.15 to 0.75). Tcrit GEI was variable, with 55.6% of the genetic variance across environments accounted for by the factor analytic model. Mean daily growth temperature in the month preceding anthesis was the most influential environmental driver of Tcrit GEI, suggesting biochemical, physiological and structural adjustments to temperature requiring different durations to manifest. These changes help protect or repair PSII upon exposure to heat stress, and may improve carbon assimilation under high temperature. To support breeding efforts to improve wheat performance under high temperature, we identified genotypes superior to commercial cultivars commonly grown by farmers, and demonstrated potential for developing genotypes with greater photosynthetic heat tolerance.

Yield-Related QTL Clusters and the Potential Candidate Genes in Two Wheat DH Populations.

In the present study, four large-scale field trials using two doubled haploid wheat populations were conducted in different environments for two years. Grain protein content (GPC) and 21 other yield-related traits were investigated. A total of 227 QTL were mapped on 18 chromosomes, which formed 35 QTL clusters. The potential candidate genes underlying the QTL clusters were suggested. Furthermore, adding to the significant correlations between yield and its related traits, correlation variations were clearly shown within the QTL clusters. The QTL clusters with consistently positive correlations were suggested to be directly utilized in wheat breeding, including 1B.2, 2A.2, 2B (4.9-16.5 Mb), 2B.3, 3B (68.9-214.5 Mb), 4A.2, 4B.2, 4D, 5A.1, 5A.2, 5B.1, and 5D. The QTL clusters with negative alignments between traits may also have potential value for yield or GPC improvement in specific environments, including 1A.1, 2B.1, 1B.3, 5A.3, 5B.2 (612.1-613.6 Mb), 7A.1, 7A.2, 7B.1, and 7B.2. One GPC QTL (5B.2: 671.3-672.9 Mb) contributed by cultivar Spitfire was positively associated with nitrogen use efficiency or grain protein yield and is highly recommended for breeding use. Another GPC QTL without negatively pleiotropic effects on 2A (50.0-56.3 Mb), 2D, 4D, and 6B is suggested for quality wheat breeding.

Primary squamous cell carcinoma of the pancreas with a large pseudocyst of the pancreas as the first manifestation: a rare case report and literature review.

BACKGROUND: Primary squamous cell carcinoma (SCC) of the pancreas with pseudocysts, especially diagnosed by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), is extremely rare. CASE PRESENTATION: A 64-year-old man was admitted to our department for abdominal distension. Two months ago, he experienced abdominal pain for 1 day and was diagnosed with acute pancreatitis in another hospital. After admission, laboratory tests showed the following: amylase 400 U/L, lipase 403 U/L, and carbohydrate antigen 19-9 (CA19-9) 347 U/mL. Abdominal computed tomography (CT) revealed pancreatitis with a pseudocyst with a diameter measuring 7 cm. During linear EUS, a large pseudocyst (5.4 × 5.2 cm) was observed in the pancreatic body. EUS-FNA was performed. We obtained specimens for histopathology and placed a plastic stent through the pancreas and stomach to drain the pseudocyst. Puncture fluid examination revealed the following: CA19-9 > 12,000 U/mL carcinoembryonic antigen (CEA) 7097.42 ng/ml, amylase 27,145.3 U/L, and lipase > 6000 U/L. Cytopathology revealed an abnormal cell mass, and cancer was suspected. Furthermore, with the result of immunohistochemistry on cell mass (CK ( +), P40 ( +), p63 ( +), CK7 (-) and Ki-67 (30%)), the patient was examined as squamous cell carcinoma (SCC). However, the patient refused surgery, radiotherapy and chemotherapy. After drainage, the cyst shrank, but the patient died 3 months after diagnosis due to liver metastasis and multiple organ failure. CONCLUSION: For patients with primary pancreatic pseudocysts with elevated serum CEA and CA19-9 levels, we should not rule out pancreatic cancer, which may also be a manifestation of primary pancreatic SCC. EUS-FNA is helpful for obtaining histopathology and cytology and thus improving diagnostic accuracy.

Contribution to Breadmaking Performance of Two Different HMW Glutenin 1Ay Alleles Expressed in Hexaploid Wheat.

Two expressed alleles of the 1Ay high-molecular-weight glutenin subunit (HMW-GS), 1Ay21* and 1AyT1, previously introduced in durum and bread wheat, were separately introgressed into the Australian bread wheat (Triticum aestivum L.) cv. Livingston. The developed lines had different allelic compositions compared to that of the parental cultivar (1Ax1), having either 1Ax21+1Ay21* or 1Ax1+1AyT1 at the Glu-A1 locus. Since 1Ax21 and 1Ax1 are known to have the same effects on quality, differences observed between the two sets of the developed lines are attributed to the two introgressed Ay genes. Yield and agronomic performance of the lines were evaluated in the field, and the protein, dough, and baking quality attributes were evaluated by large-scale quality testing. Results demonstrated that the subunit 1Ay21* increased unextractable polymeric protein by up to 14.3% and improved bread loaf volume by up to 9.2%. On the other hand, subunit 1AyT1 increased total grain protein by up to 9% along with dough elasticity. Furthermore, milling extraction was higher, and flour ash was lower in the 1Ay21* lines compared to the lines integrating 1AyT1. Both sets of the 1Ay introgression lines reduced dough-mixing time compared to the recurrent parent Livingston. The results also showed that 1Ay21* had a higher potential to improve the baking quality than 1AyT1 under the Livingston genetic background. Both alleles showed the potential to be utilized in breeding programs to improve the breadmaking quality.

Acclimation of leaf photosynthesis and respiration to warming in field-grown wheat.

Climate change and future warming will significantly affect crop yield. The capacity of crops to dynamically adjust physiological processes (i.e., acclimate) to warming might improve overall performance. Understanding and quantifying the degree of acclimation in field crops could ensure better parameterization of crop and Earth System models and predictions of crop performance. We hypothesized that for field-grown wheat, when measured at a common temperature (25°C), crops grown under warmer conditions would exhibit acclimation, leading to enhanced crop performance and yield. Acclimation was defined as (a) decreased rates of net photosynthesis at 25°C (A25 ) coupled with lower maximum carboxylation capacity (Vcmax25 ), (b) reduced leaf dark respiration at 25°C (both in terms of O2 consumption Rdark _O225 and CO2 efflux Rdark _CO225 ) and (c) lower Rdark _CO225 to Vcmax25 ratio. Field experiments were conducted over two seasons with 20 wheat genotypes, sown at three different planting dates, to test these hypotheses. Leaf-level CO2 -based traits (A25 , Rdark _CO225 and Vcmax25 ) did not show the classic acclimation responses that we hypothesized; by contrast, the hypothesized changes in Rdark_ O2 were observed. These findings have implications for predictive crop models that assume similar temperature response among these physiological processes and for predictions of crop performance in a future warmer world.

Resemblance and Difference of Seedling Metabolic and Transporter Gene Expression in High Tolerance Wheat and Barley Cultivars in Response to Salinity Stress.

To elucidate inter-specific similarity and difference of tolerance mechanism against salinity stress between wheat and barley, high tolerant wheat cv. Suntop and sensitive cv. Sunmate and tolerant barley cv. CM72 were hydroponically grown in a greenhouse with 100 mM NaCl. Glutathione, secondary metabolites, and genes associated with Na+ transport, defense, and detoxification were examined to discriminate the species/cultivar difference in response to salinity stress. Suntop and CM72 displayed damage to a lesser extent than in Sunmate. Compared to Sunmate, both Suntop and CM72 recorded lower electrolyte leakage and reactive oxygen species (ROS) production, higher leaf relative water content, and higher activity of PAL (phenylalanine ammonia-lyase), CAD (cinnamyl alcohol dehydrogenase), PPO (polyphenol oxidase), SKDH (shikimate dehydrogenase), and more abundance of their mRNA under salinity stress. The expression of HKT1, HKT2, salt overly sensitive (SOS)1, AKT1, and NHX1 was upregulated in CM72 and Suntop, while downregulated in Sunmate. The transcription factor WRKY 10 was significantly induced in Suntop but suppressed in CM72 and Sunmate. Higher oxidized glutathione (GSSG) content was accumulated in cv. CM72 and Sunmate, but increased glutathione (GSH) content and the ratio of GSH/GSSG were observed in leaves and roots of Suntop under salinity stress. In conclusion, glutathione homeostasis and upregulation of the TaWRKY10 transcription factor played a more important role in wheat salt-tolerant cv. Suntop, which was different from barley cv. CM72 tolerance to salinity stress. This new finding could help in developing salinity tolerance in wheat and barley cultivars.

Introgression of an expressed HMW 1Ay glutenin subunit allele into bread wheat cv. Lincoln increases grain protein content and breadmaking quality without yield penalty.

KEY MESSAGE: An expressed HMW glutenin subunit Glu-Ay showed positive impacts on a range of wheat processing quality and yield traits. The grain protein compositions are significantly optimised for baking, resulting in a better breadmaking quality. The unique breadmaking properties of wheat flour are related to the quality and quantity of high-molecular weight glutenin subunits (HMW-GSs) present in the grain. In the current study, the silent 1Ay HMW-GS allele, present in most bread wheat cultivars, was replaced by the expressed 1Ay21* allele, which was introgressed into Australian bread wheat cultivar Lincoln by a backcrossing and selfing scheme. Stability of gene expression and the effect of the introgressed 1Ay21* subunit on protein composition, agronomic traits, flour functionality, and breadmaking quality were studied using BC4F5 grain grown in glasshouse and field. Field phenotyping and grain quality testing showed that the 1Ay21* gene conferred significant improvements to a range of traits, including an increase in grain protein content by up to 9%, UPP% by up to 24%, bread volume by up to 28%. The glasshouse experiment and one of the field trials showed positive 1Ay21* effects on yield, while one field trial showed one significant effects. This indicates that expression of the 1Ay21* gene has the potential of simultaneously increasing protein content and grain yield under certain environment. The qualitative improvements of the grain also led to a reduction of the energy required during the baking process in addition to the significant positive effects on bread quality.

Analysis of alternatives for insulinizing patients to achieve glycemic control and avoid accompanying risks of hypoglycemia.

The aims of the present study were to explore the efficacy of glycemic control and the risks of hypoglycemia with different methods of insulin therapy, and to provide reference data for the clinical treatment of diabetes. In this retrospective study, hospitalized patients diagnosed with type 2 diabetes between March and December 2014, in the Department of Endocrinology in the First Affiliated Hospital of Wannan Medical College, were divided into three groups, including an intensive insulin analogue therapy group, a premixed insulin analogue treatment group and a premixed human insulin therapy group. The efficacy of glycemic control and the incidence of hypoglycemia were determined in each of the insulin treatment groups. Compared with the other treatment groups, the intensive insulin analogue therapy group was associated with superior blood glucose control, shorter time to reach standard insulin regimen, shorter hospitalization time, fewer fluctuations in blood glucose levels and lower insulin dosage on discharge from hospital. However, this treatment was also associated with a high risk of hypoglycemia. In conclusion, when combined with the effective prevention of hypoglycemia and appropriate nursing care (especially in hospital care), intensive insulin analogue therapy may provide the greatest benefit to patients.