Exploring genetic diversity of rice cultivars for the presence of brown planthopper (BPH) resistance genes and development of SNP marker for Bph18

Brown planthopper (BPH) is the most devastating insect pest in rice‐growing areas. Information on availability of BPH resistance alleles and their sources enhances BPH‐resistant breeding programmes. In this study, 260 highly diversified rice cultivars or breeding lines were screened for the presence of five major BPH resistance genes (Bph10, Bph13, Bph18, Bph20 and Bph21) using gene‐specific markers. The analysis revealed that 137 of the 260 cultivars possess at least one BPH resistance gene. Bph10 was predominant while Bph20 was the least distributed. Moreover, two and three different resistance gene combinations were found in the cultivars. Molecular markers play an important role in molecular breeding programmes. A tightly linked PCR‐based co‐dominant Bph18 marker was developed, which is cost effective and time effective and simpler than available Bph18 CAPS marker (7312.T4A). We strongly believe that the identified BPH‐resistant cultivars can be used as alternative resistance gene sources and also as resource for novel BPH resistance genes. The developed Bph18 marker will be highly useful in molecular breeding applications of BPH‐resistant breeding programmes.     

Predictions of soil water and crop growth dynamics using the agroecosystem models THESEUS and OPUS

The agroecosystem models THESEUS and OPUS were tested with data obtained from three agricultural experimental field plots on sandy soils without groundwater located at the moraine landscape in East Brandenburg, Germany. At each of these plots, a separate agricultural management practice was applied. Measurements of soil water contents, pressure heads, above‐ground crop biomass, and crop yield from these three plots were compared with the corresponding simulation results of both models. The comparisons of simulated with measured outputs were analyzed using the modeling‐efficiency index IA. According to these analyses, both models simulated adequately the time courses of volumetric soil water contents and above‐ground crop biomass, but the time courses of pressure heads were predicted with a lower quality by both models. As for the pressure heads, the yields simulated with both models showed greater discrepancies in comparison with the observed ones. This indicates the need of a site‐specific parameter calibration of the crop‐growth modules, especially for that included in OPUS .     

Presence of a Minor Amylose Fraction in the Central Portion of Waxy Wheat Starch Granules and Its Contribution to Granular Stability

When wheat starch granules containing various amounts of amylose (2.1–25%) were stained with 25% KI/10% I₂ solution, the granules largely changed to ghost structures below ≈5.0% amylose. The ghost showed a typical double structure: a black‐brown central portion and a red‐brown surrounding portion. The proportion of the black‐brown central portion in the ghost was strongly correlated to the amylose content (%) in the starch, that is, the black‐brown central portion decreased with a decrease in amylose. This suggests that amylose is possibly present in the black‐brown central portion. Sonication (20 kHz) followed by centrifugation of the ghost separated the black‐brown central portion from the red‐brown surrounding portion, and the amylose content in each portion was determined. The results indicated that the amylose content in the black‐brown central portion was 6.9%, whereas in the surrounding portion, it was only 1.0%. Furthermore, the central and surrounding portions were subjected to Sepharose CL‐2B gel‐filtration column chromatography and the presence of amylose could only be observed in the black‐brown central portion.     

Expression,Purification, and Functional Analysis of Three Low‐Molecular‐Weight Glutenin Subunits from Wheat Cultivar Cheyenne

Glutenins, which form the network of gluten protein, are of great importance for the quality of flour products. Glutenins can be divided into HMW and LMW subunits according to molecular weight. Three genes for LMW glutenin subunits (LMW‐GS), named lmw‐cnd1, lmw‐cnd2, and lmw‐cnd3 with open reading frames of 1,053, 903, and 969 bp, respectively, were cloned from wheat cultivar Cheyenne. Heterologous expression vectors of the three LMW‐GS were constructed, and the recombinant proteins LMW‐CND1, LMW‐CND2, and LMW‐CND3 were overexpressed in Escherichia coli. After cell disruption with ultrasound, target proteins of high purity were obtained by using Ni²⁺ affinity chromatography. Farinograph and TAPlus measurements were used to investigate the effects of the three LMW‐GS on the characteristics of flour and dough. The results showed that the addition of each LMW‐GS can lead to an increase in the elasticity of the dough. Moreover, LMW‐CND2 and LMW‐CND3 promoted the strength of the dough. All three LMW‐GS caused a decrease of hardness and increase of springiness and cohesiveness of dough according to texture profiling results. Consequently, all three LMW‐GS have positive effects on the processing characteristics of dough and can improve bread quality to different extents.     

Short-Term Effects of Arsenate-Induced Toxicity on Growth, Chlorophyll and Carotenoid Contents, and Total Content of Phenolic Compounds of Azolla filiculoides

This study evaluated the toxic effects of arsenic (As) on the growth, total antioxidant activity, total content of phenolic compounds, and content of photosynthetic pigments of Azolla filiculoides. The aquatic fern was propagated and exposed to Yoshida nutrient solution contaminated with sodium arsenate (Na₂HAsO₄??7H₂O) at six concentrations (5, 10, 20, 30, 60, and 120???g?As?mL^?1), including the control without As contamination. Azolla cultures were kept under environmental chamber conditions?26??C, 12?h photoperiod and 80% HR for 96?h. Increased As concentrations (>30???g?mL^?1) significantly diminished growth of A. filiculoides and the total content of chlorophyll and total phenolic compounds, but significantly enhanced of total carotenoid?+?xanthophylls content. The concentrations of 5 and 10???g?As?mL^?1 significantly stimulated the growth of A. filiculoides. This aquatic fern tolerates As concentrations lower than 30???g?mL^?1, and its maximum As accumulation (28???g?g^?1 dry weight) was achieved when exposed to 60???g As mL^?1, but showing clear symptoms of As toxicity.     

Combined effects of the antibiotic sulfadiazine and liquid manure on the soil microbial‐community structure and functions

Sulfonamides are the second most used antibiotic class in veterinary medicine and applied to livestock to treat bacterial infections. Subsequently, they are spread onto agricultural soils together with the contaminated manure used as fertilizer. Both manure and antibiotics affect the soil microbial community. However, the influence of different liquid manure loads on effects of antibiotics to soil microorganisms is not well understood. Therefore, we performed a microcosm experiment for up to 32 d to clarify whether the function and structure of the soil microbial community is differently affected by interactions of manure and the antibiotic sulfadiazine (SDZ). To this end selected concentrations of pig liquid manure (0, 20, 40, 80 g kg^–1) and SDZ (0, 10, 100 mg kg^–1) were combined. We hypothesized that incremental manure amendment might reduce the effect of SDZ in soils, due to an increasing sorption capacity of SDZ to organic compounds. Clear dose‐dependent effects of SDZ on microbial biomass and PLFA pattern were determined, and SDZ effects interacted with the liquid manure application rate. Soil microbial biomass increased with incremental liquid manure addition, whereas this effect was absent in the presence of additional SDZ. However, activities of enzymes such as urease and protease were only slightly affected and basal respiration was not affected by SDZ application, while differences mostly depended on the concentration of liquid manure. These results illustrated that the microbial biomass and structural composition react more sensitive to SDZ contamination than functional processes. Furthermore, effects disproportionally increased with incremental liquid manure addition, although extractable amounts of SDZ declined with increasing liquid manure application.     

Influence of ferredoxin levels on nitrate reductase activity in iron deficient lemon leaves

The relationship between nitrate reductase activity and ferredoxin levels in lemon tree leaves was studied. The experiments were carried out on leaves from full‐nutrient sufficient trees as the reference, and on leaves from trees with several nutritional stresses, mainly iron chlorosis from trees growing under Fe‐stressed conditions.

Iron deficiency reduced leaf ferredoxin concentration and consequently decreased nitrate reductase activity. Fe(II) infiltration treatments of intact leaves, as well as several incubation assays, permit to deduce the dependence of the enzymatic nitrate reduction of the leaf ferredoxin levels.     

Polyphenol oxidase activity and ortho‐diphenolic content in sunflower leaves in relation to boron nutrition.

Homogenates were prepared from the leaves of hydroponically cultivated sunflowers (Helianthus annuus, L.) under deficient, normal and toxic B conditions and the polyphenol oxidase activity together with the ortho‐diphenolic and micronutrient content was measured every week from one month to flowering.

B deficiency slightly depressed polyphenol oxidase activity and B toxicity decreased it significantly at all times, the response fitting a line versus the logarithm of the B concentration in solution. We found a positive correlation between polyphenol oxidase activity and the B content in leaves.

B action on enzymatic activity seemed not to be caused by direct interaction with substrates as the infiltration of B into deficient leaves did not restore the normal activity

According to our results we suggest that polyphenol oxidase activity may be a valid functional parameter to indicate the nutritional status of B in sunflower plants, if its specificity for B can be demonstrated.

The ortho‐diphenolic content did not change with the B levels used in our experiments. Neither did we find any correlation between enzymatic activity and the o‐diphenolic content of the leaves.