Mature Grains Research Articles

A modified Megazyme fructan assay for rapidly screening wheat starch synthase IIa mutation populations reveals high fructan accumulation in mature grains of triple null lines

Cereal grains are the major source of fructan intake with potential health benefits for human. Measurement of fructan levels in cereal breeding populations is a great challenge and time-consuming. In this study, K-FRUCHK and K-FRUC kits commercialized by Megazyme International Limited (Bray, Ireland) were modified and optimized in a 96 deep well plate and a thermal block (BioShake iQ, Q.Instruments, Jena, Germany). The modified assays are able to measure up to 91 samples per day with a range of fructan concentrations (0.4–10.8% in this experiment). Of the two assays, the modified K-FRUC assay is more desirable for measuring fructan levels in cereal grains with high starch content. This assay was successfully used to screen three wheat starch synthase IIa (SSIIa) mutation populations with a total of 466 lines. All 21 SSIIa triple null mutants showed high fructan levels (3.1–10.8%) in wholemeal flours; while all single and double nulls were similar to wild types with ∼1% of fructans. This result indicates that lack of entire SSIIa activity changes carbon flux from starch synthesis into fructan pathway. The identified 21 triple null wheat lines may have potential use for the production of high fructan staple foods.

Impact of elevated temperature on rice productivity: A case of Lalitpur, Nepal

Rice (Oryza sativa L.) is the second most important crop in the world after wheat and also the most important crop in Nepal. The production of rice is influenced by various biotic and abiotic factors. Temperature is the major constraint for the crop yield. The present experiment was conducted to study the impact of temperature on straw and crop productivity from June to October 2014. The experiment was conducted under temperature control chamber, in which temperature was elevated from the ambient level by 2ºC and 3ºC for the entire crop growth period. Grain and straw yield was measured using electronic weighing machine. Maturity of grain was 10 and 7 days earlier at elevated temperature by 3ºC and 2ºC respectively. Under similar condition of water depth, plant spacing, rice variety and soil nutrient, rise in temperature up to 2ºC is favorable for rice straw yield and crop productivity. Yield loss under elevated temperature by 3ºC is due to floret sterility. Further research on temperature resistance rice variety is necessary.

Dhurrin metabolism in the developing grain of Sorghum bicolor (L.) Moench investigated by metabolite profiling and novel clustering analyses of time-resolved transcriptomic data.

BackgroundThe important cereal crop Sorghum bicolor (L.) Moench biosynthesize and accumulate the defensive compound dhurrin during development. Previous work has suggested multiple roles for the compound including a function as nitrogen storage/buffer. Crucial for this function is the endogenous turnover of dhurrin for which putative pathways have been suggested but not confirmed.ResultsIn this study, the biosynthesis and endogenous turnover of dhurrin in the developing sorghum grain was studied by metabolite profiling and time-resolved transcriptome analyses. Dhurrin was found to accumulate in the early phase of grain development reaching maximum amounts 25 days after pollination. During the subsequent maturation period, the dhurrin content was turned over, resulting in only negligible residual dhurrin amounts in the mature grain. Dhurrin accumulation correlated with the transcript abundance of the three genes involved in biosynthesis. Despite the accumulation of dhurrin, the grains were acyanogenic as demonstrated by the lack of hydrogen cyanide release from macerated grain tissue and by the absence of transcripts encoding dhurrinases. With the missing activity of dhurrinases, the decrease in dhurrin content in the course of grain maturation represents the operation of hitherto uncharacterized endogenous dhurrin turnover pathways. Evidence for the operation of two such pathways was obtained by metabolite profiling and time-resolved transcriptome analysis. By combining cluster- and phylogenetic analyses with the metabolite profiling, potential gene candidates of glutathione S-transferases, nitrilases and glycosyl transferases involved in these pathways were identified. The absence of dhurrin in the mature grain was replaced by a high content of proanthocyanidins. Cluster- and phylogenetic analyses coupled with metabolite profiling, identified gene candidates involved in proanthocyanidin biosynthesis in sorghum.ConclusionsThe results presented in this article reveal the existence of two endogenous dhurrin turnover pathways in sorghum, identify genes putatively involved in these transformations and show that dhurrin in addition to its insect deterrent properties may serve as a storage form of reduced nitrogen. In the course of sorghum grain maturation, proanthocyanidins replace dhurrin as a defense compound. The lack of cyanogenesis in the developing sorghum grain renders this a unique experimental system to study CNglc synthesis as well as endogenous turnover.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-3360-4) contains supplementary material, which is available to authorized users.

Tissue specific transcript profiling of wheat phosphate transporter genes and its association with phosphate allocation in grains.

Approaches enabling efficient phosphorus utilization in crops are of great importance. In cereal crop like wheat, utilization of inorganic phosphate (Pi) is high and mature grains are the major sink for Pi utilization and storage. Research that addresses the importance of the Pi homeostasis in developing grains is limited. In an attempt to understand the Pi homeostasis in developing wheat grains, we identified twelve new phosphate transporters (PHT), these are phyologentically well distributed along with the members reported from Arabidopsis and rice. Enhanced expression of PHT1-subfamily genes was observed in roots subjected to the Pi starvation suggesting their active role in Pi homeostasis. Differential expression patterns of all the PHT genes during grain filling stages suggested their importance in the filial tissues. Additionally, high accumulation of Pi and total P in aleurone correlates well with the expression of TaPHTs and other phosphate starvation related genes. Tissue specific transcript accumulation of TaPHT1.1, TaPHT1.2, TaPHT1.4 in aleurone; TaPHT3.1 in embryo and TaPHT4.2 in the endosperm was observed. Furthermore, their transcript abundance was affected in low phytate wheat grains. Altogether, this study helps in expanding the knowledge and prioritize the candidate wheat Pi-transporters to modulate the Pi homeostasis in cereal grains.

Barley HvPAPhy_a as transgene provides high and stable phytase activities in mature barley straw and in grains.

SummaryThe phytase purple acid phosphatase (HvPAPhy_a) expressed during barley seed development was evaluated as transgene for overexpression in barley. The phytase was expressed constitutively driven by the cauliflower mosaic virus 35S‐promoter, and the phytase activity was measured in the mature grains, the green leaves and in the dry mature vegetative plant parts left after harvest of the grains. The T2‐generation of HvPAPhy_a transformed barley showed phytase activity increases up to 19‐fold (29 000 phytase units (FTU) per kg in mature grains). Moreover, also in green leaves and mature dry straw, phytase activities were increased significantly by 110‐fold (52 000 FTU/kg) and 57‐fold (51 000 FTU/kg), respectively. The HvPAPhy_a‐transformed barley plants with high phytase activities possess triple potential utilities for the improvement of phosphate bioavailability. First of all, the utilization of the mature grains as feed to increase the release of bio‐available phosphate and minerals bound to the phytate of the grains; secondly, the utilization of the powdered straw either directly or phytase extracted hereof as a supplement to high phytate feed or food; and finally, the use of the stubble to be ploughed into the soil for mobilizing phytate‐bound phosphate for plant growth.

Resistance sources for wheat aphid : An update

Wheat (Triticum aestivum L.) is a major crop with largest area under cultivation in India and plays a significant role in economic stability of the country. Many insect pests attack wheat in India, severe damage is caused by aphids as serious pest of wheat crop which cause yield losses either directly (35-40%) by sucking the sap of the plants or indirectly (20-80%) by transmitting viral and fungal diseases. They can multiply very rapidly under favourable conditions on leaves, stems and inflorescence. The infestation causes severe distortion of leaves and inflorescence and can significantly decrease the yield through direct feeding. The production of chlorophyll (green colour) is prevented by the attack of aphid resulting in curling of leaves and delayed head emergence causing improper maturity of grains. The aphid incidence level differed in different cultivars of wheat. The resistance of crop is an index of the balance that exists between the preference of the pest for crop and its antibiosis against it. The mechanical barriers possessed by the plants which prevented insects from feeding or ovipositing on them. The infestation significantly affected the root dry weight, number and height of tillers and number of spikes per head. Leaf epicutticular wax, ultra structure and leaf trichome were different on susceptible wheat cultivar and resistant cultivar. Leaf trichome density and position may act as a physical obstracle to the Russian wheat aphid feeding. An increased amount of glutamic acid, glutamine, alpha amino butyric acid, phenylalanine and proline and less methionine, produce resistance in wheat plants against aphids. Hydroxamic acids (Hx) have been shown to be a major biochemical mechanism of resistance of wheat to aphids, acting through antibiosis and feeding deterrency. How to view point the article : Patil, S.D., Padhye, A.P. and Katare, Subhash (2016). Resistance sources for wheat aphid : An update. Internat. J. Plant Protec., 9(2) : 628-631, DOI : 10.15740/ HAS/IJPP/9.2/628-631.

Reproductive development and grain quality in maize in response to application of Zn alone or with B in soil low in available Zn and B

ABSTRACTA pot culture experiment was conducted on a soil marginally deficient in diethylenetriaminepentaacetic acid (DTPA) extractable zinc under the glass house conditions of Lucknow University to observe the effect of zinc (Zn) alone and a combination of Zn with boron (B) on the growth and reproductive yield of maize. Studies conducted on plant height, dry matter and reproductive yield and tissue element concentration in leaves and grains at harvest showed significant increase over the control. Activities of enzymes, carbonic anhydrase and superoxide dismutase determined in comparable middle leaves increased with the application of both the nutrients. Pollen diameter, pollen-producing capacity of mature anthers, grain protein, starch and phytate content were also positively correlated with the addition of nutrients. The residual value of available Zn and B in soil left after the removal of crop was found good enough to sustain the next crop.

Metabolism and Residues of 2,4-Dichlorophenoxyacetic Acid in DAS-40278-9 Maize (Zea mays) Transformed with Aryloxyalkanoate Dioxygenase-1 Gene.

DAS-40278-9 maize, which is developed by Dow AgroSciences, has been genetically modified to express the aryloxyalkanoate dioxygenase-1 (AAD-1) protein and is tolerant to phenoxy auxin herbicides, such as 2,4-dichlorophenoxyacetic acid (2,4-D). To understand the metabolic route and residue distribution of 2,4-D in DAS-40278-9 maize, a metabolism study was conducted with 14C-radiolabeled 2,4-D applied at the maximum seasonal rate. Plants were grown in boxes outdoors. Forage and mature grain, cobs, and stover were collected for analysis. The metabolism study showed that 2,4-D was metabolized to 2,4-dichlorophenol (2,4-DCP), which was then rapidly conjugated with glucose. Field-scale residue studies with 2,4-D applied at the maximum seasonal rate were conducted at 25 sites in the U.S. and Canada to measure the residues of 2,4-D and free and conjugated 2,4-DCP in mature forage, grain, and stover. Residues of 2,4-D were not detectable in the majority of the grain samples and averaged <1.0 and <1.5 μg/g in forage and stover, respectively. Free plus conjugated 2,4-DCP was not observed in grain and averaged <1.0 μg/g in forage and stover.

The wheat ABA hypersensitive ERA8 mutant is associated with increased preharvest sprouting tolerance and altered hormone accumulation

Wheat preharvest sprouting (PHS) is the germination of mature grain on the mother plant when rain occurs before harvest. Higher abscisic acid (ABA) hormone levels and sensitivity are associated with higher seed dormancy and PHS tolerance. Consistent with this, the ABA hypersensitive ENHANCED RESPONSE TO ABA8 (ERA8) mutant resulted in increased dormancy and PHS tolerance in soft white spring wheat ‘Zak’. ERA8 seeds were initially less responsive to germination-rescue by the hormone gibberellin (GA). ERA8 gained GA and lost ABA sensitivity more slowly than wild-type during dormancy loss through after-ripening and cold imbibition. This study examined if increased ABA sensitivity in ERA8 likely resulted from increased ABA signaling or increased ABA hormone levels. Zak ERA8 had higher initial grain dormancy although endogenous embryo ABA levels were similar in Zak ERA8 and wild-type, suggesting that increased dormancy was due to increased ABA signaling rather than increased ABA accumulation. ABA levels declined with Zak ERA8 after-ripening, suggesting that ABA turnover is not defective. Elevated ERA8 dormancy was also associated with increased embryonic jasmonic acid-Ile and aleurone indole-3-acetic acid (IAA) levels. The possible implication that other plant hormones may influence wheat seed dormancy and germination are discussed.

Our daily bread has more benefits than we thought

Whole grains in bread and other foods can add a healthy dose of vitamins, minerals, protein, and fiber to our diets. But scientists such as Inge S. Fomsgaard of Aarhus University are looking further at how some lesser-known bioactive grain compounds called benzoxazinoids, or BXs for short, can improve health through their immune-boosting properties. Scientists have known for a few decades that BXs help protect young cereal grain plants such as rye, wheat, and corn against weeds, insects, and diseases. But it wasn’t until 2009 that Fomsgaard’s group discovered that mature grains also contain BXs. Fomsgaard and her colleagues subsequently found that BXs survive food processing and that the composition and concentration of the compounds are enhanced via enzymatic processes during malting or baking. Using mass-spectrometry-based metabolomics methods in rats, pigs, and people, the researchers have shown that BXs are taken up, distributed, and metabolized by mammals and that a

Response Differences Stability Model Simplify the Identification of Stable Rice Genotypes for Low Temperature Environment

Stable genotype is necessary for long-term grain security to the farmers. Developing site specific variety is a good way of maintaining diversity and getting potential yield. Simple parameters were estimated based on nine rice genotypes evaluated under low temperature at three different altitudinal environments of Jumla, Lumle and Khumaltar. The genotypes were influenced by the varying conditions and G x E interaction which was highly significant for maturity, bearing tiller, and plant height and grain yield indicating responses of the rice genotype in different environments. These traits are very important for adoption of genotypes in farmers’ field. It can be inferred that there is a possibility of developing site-specific variety which are stable and adoptable across these environments. Cold environment rice genotypes of NR10288-015J-15J-7, Chhommrong and NR10293 are most stable and ideally adapted in cold stress environment. NR 10346 is the site-specific genotype adapted to favorable environments. Hence, these genotypes could be used in breeding programs for increasing the productivity of rice in cold environment and for general cultivation as well.Agronomy Journal of Nepal (Agron JN) vol. 4, Page: 1-8, 2016

Mass Spectrometric Imaging of Wheat (Triticum spp.) and Barley (Hordeum vulgare L.) Cultivars: Distribution of Major Cell Wall Polysaccharides According to Their Main Structural Features.

Arabinoxylans (AX) and (1→3),(1→4)-β-glucans (BG) are the main components of cereal cell walls and influence many aspects of their end uses. Important variations in the composition and structure of these polysaccharides have been reported among cereals and cultivars of a given species. In this work, the spatial distribution of AX and BG in the endosperm of mature grains was established for nine wheat varieties and eight barley varieties using enzymatically assisted mass spectrometry imaging (MSI). Important structural features of the AX and BG polymers that were previously shown to influence their physicochemical properties were assessed. Differences in the distribution of AX and BG structures were observed, both within the endosperm of a given cultivar and between wheat and barley cultivars. This study provides a unique picture of the structural heterogeneity of AX and BG polysaccharides at the scale of the whole endosperm in a series of wheat and barley cultivars. Thus, it can participate meaningfully in a strategy aiming at understanding the structure-function relationships of these two polymers.

Aroma volatile analyses and 2AP characterization at various developmental stages in Basmati and Non-Basmati scented rice (Oryza sativa L.) cultivars.

BackgroundRice plant growth is comprised of distinct phases, such as vegetative, reproductive, grain filling and maturity phases. In these phases synthesis and availability of primary and secondary metabolites including volatile organic compounds (VOC’s) is highly variable. In scented rice, aroma volatiles are synthesized in aerial plant parts and deposited in mature grains. There are more than 100 VOCs reported to be responsible for flavor in basmati rice. It will be interesting to keep track of aroma volatiles across the developmental stages in scented rice. Therefore, the aroma volatiles contributing in aroma with special reference to the major compound 2 acetyl-1-pyrroline (2AP) were screened at seven developmental stages in scented rice cultivars Basmati-370 and Ambemohar-157 along with non-scented rice cultivar IR-64 as a control following HS-SPME-GC-MS method. In addition, the expression levels of key genes and precursor levels involved in 2AP biosynthesis were studied.ResultsThe study indicated that volatilome of scented rice cultivars is more complex than non-scented rice cultivar. N-heterocyclic class was the major distinguishing class between scented from non-scented rice. A total of 14 compounds including, 2AP were detected specifically in scented rice cultivars. Maximum number of compounds were synthesized at seedling stage and decreased gradually at reproductive and maturity. The seedling stage is an active phase of development where maximum number green leaf volatiles were synthesized which are known to act as defense molecules for protection of young plant parts. Among the 14 odor active compounds (OACs), 10 OACs were accumulated at higher concentrations significantly in scented rice cultivars and contribute in the aroma. 2AP content was highest in mature grains followed by at booting stage. Gene expression analysis revealed that reduced expression of betaine aldehyde dehydrogenase 2 (badh2) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and elevated level of triose phosphate isomerase (TPI) and Δ1-Pyrolline-5-carboxylic acid synthetase (P5CS) transcript enhances 2AP accumulation.ConclusionsMost diverse compounds were synthesized at seedling stage and OACs were accumulated more at flowering followed by seedling stage. Distinct accumulation pattern exists for 2AP and other aroma volatiles at various developmental stages. The study revealed the mechanism of 2AP accumulation such that 2AP in mature grains might be transported from leaves and stem sheath and accumulation takes place in grains.Electronic supplementary materialThe online version of this article (doi:10.1186/s12284-016-0113-6) contains supplementary material, which is available to authorized users.

Distinct expression and function of carotenoid metabolic genes and homoeologs in developing wheat grains.

Backgroundβ-carotene, the most active provitamin A molecule produced by plants, plays important roles in human nutrition and health. β-carotene does not usually accumulate in the endosperm (i.e. flour) of mature wheat grains, which is a major food source of calories for humans. Therefore, enriching β-carotene accumulation in wheat grain endosperm will enable a sustainable dietary supplementation of provitamin A. Several metabolic genes affecting β-carotene accumulation have already been isolated from wheat, including phytoene synthase 1 (PSY1), lycopene ε-cyclase (LCYe) and carotenoid β-ring hydroxylase1/2 (HYD1/2).ResultsIn this work, we cloned and biochemically characterized two carotenoid cleavage dioxygenases (CCDs), CCD1 and CCD4, from wheat. While CCD1 homoeologs cleaved β-apo-8′-carotenal, β-carotene, lutein and zeaxanthin into apocarotenoid products, CCD4 homoeologs were inactive towards these substrates in in vitro assays. When analyzed by real-time qPCR, PSY1, LCYe, HYD1/2 and CCD1/4 homoeologs showed distinct expression patterns in vegetative tissues and sections of developing tetraploid and hexaploid wheat grains, suggesting that carotenoid metabolic genes and homoeologs are differentially regulated at the transcriptional level in wheat.ConclusionsThe CCD1/4 enzyme activity and the spatial-temporal gene expression data provide critical insights into the specific carotenoid metabolic gene homoeologs that control β-carotene accumulation in wheat grain endosperm, thus establishing the knowledge base for generation of wheat varieties with enhanced β-carotene in the endosperm through breeding and genome editing approaches.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-016-0848-7) contains supplementary material, which is available to authorized users.

Forage production and quality of common vetch mixtures with barley, oat and triticale in four phenological stages

Para determinar la producción y la calidad del forraje de la mezcla de veza común con cebada, avena, y triticale en dos proporciones de semilla (65:35; 35:65) durante cuatro etapas fenológicas, se estableció un experimento en un diseño de bloques completos al azar con arreglo factorial (3x4x4) con cuatro repeticiones. En mezclas de cultivos la mayor producción de materia seca (MS) la obtuvo la asociación avena-veza con 16.6 t ha-1 y en proporción de cultivos la avena-veza (65:35) produjo 19.9 t ha-1, durante la etapa grano masoso (P&lt;0.001). La mayor cantidad de proteína cruda la obtuvieron las mezclas avena-veza (178 g kg-1 MS) y triticale-veza (161 g kg-1 MS) durante la etapa de embuche. Los menores valores de fibra detergente neutra los presentaron el monocultivo veza y su mezcla con avena (35:65), durante la etapa grano maduro (P&lt;0.001). Las menores cantidades de fibra detergente ácida lo obtuvieron los monocultivos avena, veza y triticale durante la etapa grano lechoso (P&lt;0.001). El mayor porcentaje de nutrientes digestibles totales lo obtuvo el monocultivo veza y su mezcla con cebada (65:35) durante la etapa grano lechoso, respectivamente (P&lt;0.001). El contenido de energía neta de lactación y el valor relativo de forraje fue mayor para el monocultivo veza (P&lt;0.001). Se concluye que la producción y calidad del forraje en mezcla de veza con cereales (cebada, avena y triticale) dependen de la etapa de cosecha. En este estudio, la mezcla avena-veza logró mayor producción de materia seca y mejor contenido de proteína cruda. Además, el valor relativo del forraje fue más alto durante la etapa grano maduro.

Field Application of Benzothiadiazole (BTH) to Oats (Avena sativa): Effects on Crown Rust Resistance and Avenanthramide Production

Avenanthramides are phenolic antioxidants produced in oat (Avena sativa L.) in response to fungal infection and, as shown in greenhouse experiments, by treatment with plant defense activators, such as benzothiadiazole (BTH). Presented here are the results of application of BTH under field conditions. Field trials were conducted in 2013 using four application rates, approximating manufacturer's recommendations, on two oat cultivars and in 2014 using three application rates on three oat cultivars. The results showed a subtle but demonstrable effect of increased avenanthramide production in vegetative tissue and mature grain and enhanced resistance to crown rust infection. Gene expression of pathogenesis related protein‐1 (PR‐1), phenylalanine ammonia lyase (PAL) and hydroxycinnamoyl‐CoA:hydroxyanthranilate hydroxycinnamoyl‐CoA transferase (HHT) was also monitored by RT‐qPCR. Both PR‐1 and PAL expression were demonstrably up‐regulated in the field trials; HHT was not. However, greenhouse experiments showed all three genes to be elicited with 63‐, 9‐, and 3‐fold increases, respectively. Thus, field application of plant defense activators can effectively enhance crown rust resistance and avenanthramide production in oat by up‐regulating certain metabolic pathways; their practical application, however, will require substantial investigative efforts.

Characteristics of the grain-filling process and starch accumulation of high-yield common buckwheat ‘cv. Fengtian 1’ and tartary buckwheat ‘cv. Jingqiao 2’

High-yield common buckwheat ‘cv. Fengtian 1’ (FT1) and tartary buckwheat ‘cv. Jingqiao 2’ (JQ2) were selected to investigate the characteristics of the grain-filling process and starch accumulation of high-yield buckwheat. FT1 had an average yield that was 43.0% higher than that of the control ‘cv. Tongliaobendixiaoli’ (TLBDXL) in two growing seasons, while JQ2 had an average yield that was 27.3% higher than that of the control ‘cv. Chuanqiao 2’ (CQ2). The Richards equation was utilized to evaluate the grain-filling process of buckwheat. Both FT1 and JQ2 showed higher values of initial growth power and final grain weight and longer linear increase phase, compared with respective control. These values suggest that the higher initial increasing rate and the longer active growth period during grain filling play important roles to increase buckwheat yield. Similar patterns of starch, amylose and amylopectin accumulation were detected in common buckwheat, leading to similar concentration of each constituent at maturity in FT1 and TLBDXL. Tartary buckwheat showed an increasing accumulation pattern of amylose in developing seeds, which differed from that of starch and amylopectin. This pattern led to a significant difference of the concentrations of amylose and amylopectin at maturity between JQ2 and CQ2, the mechanisms of which remained unclear. Nevertheless, both FT1 and JQ2 showed increased starch, amylose, and amylopectin accumulation during the physiological maturity of grains. The results suggest that prolonging the active grain-filling period to increase carbohydrate partitioning from source to seed sink can be an effective strategy to improve buckwheat yield.

Silencing of ABCC13 transporter in wheat reveals its involvement in grain development, phytic acid accumulation and lateral root formation.

Low phytic acid is a trait desired in cereal crops and can be achieved by manipulating the genes involved either in its biosynthesis or its transport in the vacuoles. Previously, we have demonstrated that the wheat TaABCC13 protein is a functional transporter, primarily involved in heavy metal tolerance, and a probable candidate gene to achieve low phytate wheat. In the current study, RNA silencing was used to knockdown the expression of TaABCC13 in order to evaluate its functional importance in wheat. Transgenic plants with significantly reduced TaABCC13 transcripts in either seeds or roots were selected for further studies. Homozygous RNAi lines K1B4 and K4G7 exhibited 34-22% reduction of the phytic acid content in the mature grains (T4 seeds). These transgenic lines were defective for spike development, as characterized by reduced grain filling and numbers of spikelets. The seeds of transgenic wheat had delayed germination, but the viability of the seedlings was unaffected. Interestingly, early emergence of lateral roots was observed in TaABCC13-silenced lines as compared to non-transgenic lines. In addition, these lines also had defects in metal uptake and development of lateral roots in the presence of cadmium stress. Our results suggest roles of TaABCC13 in lateral root initiation and enhanced sensitivity towards heavy metals. Taken together, these data demonstrate that wheat ABCC13 is functionally important for grain development and plays an important role during detoxification of heavy metals.

Proteomics of Durum Wheat Grain during Transition to Conservation Agriculture.

Nitrogen management in combination with sustainable agronomic techniques can have a great impact on the wheat grain proteome influencing its technological quality. In this study, proteomic analyses were used to document changes in the proportion of prolamins in mature grains of the newly released Italian durum wheat cv Achille. Such an approach was applied to wheat fertilized with urea (UREA) and calcium nitrate (NITRATE), during the transition to no-till Conservation Agriculture (CA) practice in a Mediterranean environment. Results obtained in a two-years field experiment study suggest low molecular weight glutenins (LMW-GS) as the fraction particularly inducible regardless of the N-form. Quantitative analyses of LMW-GS by 2D-GE followed by protein identification by LC-ESI-MS/MS showed that the stable increase was principally due to C-type LMW-GS. The highest accumulation resulted from a physiologically healthier state of plants treated with UREA and NITRATE. Proteomic analysis on the total protein fraction during the active phase of grain filling was also performed. For both N treatments, but at different extent, an up-regulation of different classes of proteins was observed: i) enzymes involved in glycolysis and citric acid cycles which contribute to an enhanced source of energy and carbohydrates, ii) stress proteins like heat shock proteins (HSPs) and antioxidant enzymes, such as peroxidases and superoxide dismutase which protect the grain from abiotic stress during starch and storage protein synthesis. In conclusion N inputs, which combined rate with N form gave high yield and improved quality traits in the selected durum wheat cultivar. The specific up-regulation of some HSPs, antioxidant enzymes and defense proteins in the early stages of grain development and physiological indicators related to fitness traits, could be useful bio-indicators, for wheat genotype screening under more sustainable agronomic conditions, like transition phase to no-till CA in Mediterranean environments.

Relationship between Fusarium spp. diversity and mycotoxin contents of mature grains in southern Belgium

ABSTRACTOver a 4-year period (2010–13), a survey aiming at determining the occurrence of Fusarium spp. and their relations to mycotoxins in mature grains took place in southern Belgium. The most prevalent species were F. graminearum, F. avenaceum, F. poae and F. culmorum, with large variations between years and locations. An even proportion of mating type found for F. avenaceum, F. culmorum, F. cerealis and F. tricinctum is usually a sign of ongoing sexual recombination. In contrast, an unbalanced proportion of mating type was found for F. poae and no MAT1-2 allele was present in the F. langsethiae population. Genetic chemotyping indicates a majority of deoxynivalenol (DON)-producing strains in F. culmorum (78%, all 3-ADON producers) and F. graminearum (95%, mostly 15-ADON producers), while all F. cerealis strains belong to the nivalenol (NIV) chemotype. Between 2011 and 2013, DON, NIV, enniatins (ENNs) and moniliformin (MON) were found in each field in various concentrations. By comparison, beauvericin (BEA) was scarcely detected and T-2 toxin, zearalenone and α- and β-zearalenols were never detected. Principal component analysis revealed correlations of DON with F. graminearum, ENNs and MON with F. avenaceum and NIV with F. culmorum, F. cerealis and F. poae. BEA was associated with the presence of F. tricinctum and, to a lesser extent, with the presence of F. poae. The use of genetic chemotype data revealed that DON concentrations were mostly influenced by DON-producing strains of F. graminearum and F. culmorum, whereas the concentrations of NIV were influenced by the number of NIV-producing strains of both species added to the number of F. cerealis and F. poae strains. This study emphasises the need to pay attention to less-studied Fusarium spp. for future Fusarium head blight management strategies, as they commonly co-occur in the field and are associated with a broad spectrum of mycotoxins.