SWEET11b transports both sugar and cytokinin in developing barley grains

Even though Sugars Will Eventually be Exported Transporters (SWEETs) have been found in every sequenced plant genome, a comprehensive understanding of their functionality is lacking. In this study, we focused on the SWEET family of barley (Hordeum vulgare). A radiotracer assay revealed that expressing HvSWEET11b in African clawed frog (Xenopus laevis) oocytes facilitated the bidirectional transfer of not only just sucrose and glucose, but also cytokinin. Barley plants harboring a loss-of-function mutation of HvSWEET11b could not set viable grains, while the distribution of sucrose and cytokinin was altered in developing grains of plants in which the gene was knocked down. Sucrose allocation within transgenic grains was disrupted, which is consistent with the changes to the cytokinin gradient across grains, as visualized by magnetic resonance imaging and Fourier transform infrared spectroscopy microimaging. Decreasing HvSWEET11b expression in developing grains reduced overall grain size, sink strength, the number of endopolyploid endosperm cells, and the contents of starch and protein. The control exerted by HvSWEET11b over sugars and cytokinins likely predetermines their synergy, resulting in adjustments to the grain's biochemistry and transcriptome

Is FLT3 internal tandem duplication an unfavorable risk factor for high risk children with acute myeloid leukemia? : Polish experience

According to the AML-BFM 2004 Interim, a treatment protocol used in Poland since 2005, presence of FLT3 internal tandem duplication (FLT3/ITD) qualifies a patient with acute myeloid leukemia (AML) to a high-risk group (HRG). The present study was aimed to identify the prevalence of FLT3/ITD in children with AML in Poland and to evaluate its prognostic significance in the HRG patients. Out of 291 children with de novo AML treated in 14 Polish centers between January 2006 and December 2012, samples from 174 patients were available for FLT3/ITD analysis. Among study patients 108 children (61.7%) were qualified to HRG. Genomic DNA samples from bone marrow were tested for identification of FLT3/ITD mutation by PCR amplification of exon 14 and 15 of FLT3 gene. Clinical features and treatment outcome in patients with and without FLT3/ITD were analyzed in the study. The FLT3/ITD was found in 14 (12.9%) of 108 HRG children. There were no significant differences between children with and without FLT3/ITD in age and FAB distribution. The white blood cells count in peripheral blood at diagnosis was significantly higher (p <0.01) in the children with FLT3/ITD. Over 5-year overall survival rate for FLT3/ITD positive children was worse (42.4%) comparing to FLT3/ITD negative children (58.9%), but the statistical difference was not significant. However, over 5-year survivals free from treatment failures were similar. The FLT3/ITD rate (12.9%) observed in the study corresponded to the published data. There was no significant impact of FLT3/ITD mutation on survival rates, although further studies are needed on this subject

Repression of barley cathepsins, HvPap-19 and HvPap-1, differentially alters grain composition and delays germination

12 Pág. Centro de Biotecnología y Genómica de PlantasDuring barley germination, cysteine proteases are essential in the mobilization of storage compounds providing peptides and amino acids to sustain embryo growth until photosynthesis is completely established. Knockdown barley plants, generated by artificial miRNA, for the cathepsins B- and F-like HvPap-19 and HvPap-1 genes, respectively, showed less cysteine protease activities and consequently lower protein degradation. The functional redundancy between proteases triggered an enzymatic compensation associated with an increase in serine protease activities in both knockdown lines, which was not sufficient to maintain germination rates and behaviour. Concomitantly, these transgenic lines showed alterations in the accumulation of protein and carbohydrates in the grain. While the total amount of protein increased in both transgenic lines, the starch content decreased in HvPap-1 knockdown lines and the sucrose concentration was reduced in silenced HvPap-19 grains. Consequently, phenotypes of HvPap-1 and HvPap-19 artificial miRNA lines showed a delay in the grain germination process. These data demonstrate the potential of exploring the properties of barley proteases for selective modification and use in brewing or in the livestock feeding industry.This research was supported by the Ministerio de Economia, Industria y Competitividad of Spain (projects BIO2014-53508-R, BIO17-83472-R, and RyC17MESFB). RyC grant (RyC2017-21814) from the MEIC and Plan Propio from the UPM-financed MES. We gratefully appreciate comments from Dr Ljudmilla Borisjuk and Dr Volodymyr Radchuk from the IPK-Gatersleben (Germany).Peer reviewe

A mechanistic view on lodging resistance in rye and wheat: a multiscale comparative study

The development of crop varieties that are resistant to lodging is a top priority for breeding programmes. Herein, we characterize the rye mutant Stabilstroh' ('stable straw') possessing an exceptional combination of high lodging resistance, tall posture, and high biomass production. Nuclear magnetic resonance imaging displayed the 3-dimensional assembly of vascular bundles in stem. A higher number of vascular bundles and a higher degree of their incline were features of lodging-resistant versus lodging-prone lines. Histology and electron microscopy revealed that stems are fortified by a higher proportion of sclerenchyma and thickened cell walls, as well as some epidermal invaginations. Biochemical analysis using Fourier-transform infrared spectroscopy and inductively coupled plasma-optical emission spectrometry further identified elevated levels of lignin, xylan, zinc, and silicon as features associated with high lodging resistance. Combined effects of above features caused superior culm stability. A simplistic mathematical model showed how mechanical forces distribute within the stem under stress. Main traits of the lodging-resistant parental line were heritable and could be traced back to the genetic structure of the mutant. Evaluation of lodging-resistant wheat 'Babax' ('Baviacora') versus contrasting, lodging-prone, genotype Pastor agreed with above findings on rye. Our findings on mechanical stability and extraordinary culm properties may be important for breeders for the improvement of lodging resistance of tall posture cereal crops

Grain filling in barley relies on developmentally controlled programmed cell death

Cereal grains contribute substantially to the human diet. The maternal plant provides the carbohydrate and nitrogen sources deposited in the endosperm, but the basis for their spatial allocation during the grain filling process is obscure. Here, vacuolar processing enzymes have been shown to both mediate programmed cell death (PCD) in the maternal tissues of a barley grain and influence the delivery of assimilate to the endosperm. The proposed centrality of PCD has implications for cereal crop improvement