The expression of a bean PGIP in transgenic wheat confers increased resistance to the fungal pathogen Bipolaris sorokiniana

In several plant-pathogen interactions to overcome the barrier represented by cell wall most fungal pathogens produce a variety of hydrolytic enzymes and between them PGs are one of the first to be secreted. We demonstrate that transgenic wheat plants expressing PvPGIP2 showed a significant reduction of symptoms following the infection of Bipolaris sorokiniana suggesting that pectin hydrolysis is an important step for fungal penetration of wheat plants.In molti sistemi pianta patogeno i patogeni al fine di superare l’ostacolo rappresentato dalla parete cellulare producono degli enzimi idrolitici tra cui le Poligalatturonasi ( PG) sono tra i primi ad essere secreti. In questo lavoro dimostriamo che piante transgeniche di frumento sovraesprimenti la PvPGIP2 mostrano una significativa riduzione nella sintomatologia riscontrata in seguito ad infezione con Bipolaris sorokiniana suggerendo che l’idrolisi della pectina rappresenta uno step importante per la penetrazione e la colonizzazione dei tessuti di frumento.L'articolo é disponibile sul sito dell'editore: http://www.apsjournals.apsnet.or

Advancing Crop Transformation in the Era of Genome Editing

Plant transformation has enabled fundamental insights into plant biology and revolutionized commercial agriculture. Unfortunately, for most crops, transformation and regeneration remain arduous even after more than 30 years of technological advances. Genome editing provides novel opportunities to enhance crop productivity but relies on genetic transformation and plant regeneration, which are bottlenecks in the process. Here, we review the state of plant transformation and point to innovations needed to enable genome editing in crops. Plant tissue culture methods need optimization and simplification for efficiency and minimization of time in culture. Currently, specialized facilities exist for crop transformation. Single-cell and robotic techniques should be developed for high-throughput genomic screens. Plant genes involved in developmental reprogramming, wound response, and/or homologous recombination should be used to boost the recovery of transformed plants. Engineering universal Agrobacterium tumefaciens strains and recruiting other microbes, such as Ensifer or Rhizobium, could facilitate delivery of DNA and proteins into plant cells. Synthetic biology should be employed for de novo design of transformation systems. Genome editing is a potential game-changer in crop genetics when plant transformation systems are optimized

Variant high-molecular-weight glutenin subunits arising from biolistic transformation of wheat

Genetic transformation via the biolistic method has been used to introduce genes encoding natural and novel high-molecular-weight glutenin subunits (HMW-GS) into wheat. The appearance of new seed proteins of sizes not predicted by the transgene coding sequences was noted in some experiments. In this report, the identities of thirteen of these novel proteins were determined by tandem mass spectrometry (MS/MS). Seven different proteins larger than and two proteins smaller than the native protein were shown to contain peptides from 1Dx5. A novel protein found in some progeny of crosses between a transgenic plant and Great Plains winter wheats was larger than but contained several peptides from 1Dy10. In one line, a protein larger than and a protein smaller than HMW-GS each contained peptides from the N- and C-terminus of 1Dx5 and from the repeat region of 1Dy10. In a sixth transgenic line, the native Bx7 gene was apparently replaced by a gene that encodes a larger version of 1Bx7. The variant proteins accumulate in the polymeric protein fraction, indicating that they can form inter-molecular disulfide bonds. These results show that novel proteins found in some transformants are encoded by altered versions of either the transforming or endogenous HMW-GS genes

Quality and Agronomic Effects of Three High-Molecular-Weight Glutenin Subunit Transgenic Events in Winter Wheat

Quality and agronomic effects of three transgenic high molecular weight glutenin subunit (HMW-GS) events were characterized in advanced generation breeding lines of hard winter wheat (Triticum aestivum L.) in three Nebraska crop years. Two or the transgenic events studied, Dy10-E and B52a-6, ovenexpress HMW-GS IDY10, while the third event, Dx5 +Dy10-H, overexpresses HMW-GS IDx5 and to a much lesser extent. IDY10. In addition, novel proteins possessing solubility characteristics defined as HMW-GS were present in Dx5+Dy10-H and B52a-6. Average grain yield of lines derived from the three transgenic events was statistically lower than that of a group of control cultivars and advanced breeding lines. but not lower than the mean values of respective nontransgenic siblings. Grain hardness was influenced by one of the events. Dx5+Dy10-H produced harder kernels than controls. its nontransgenic siblings. and the two additional transgenic events. All three events produced doughs with unusual mixing properties. although not likely to be directly useful in commercial applications. As a consequence. loaf volumes were depressed to variable degrees by the three events. The results indicated that over-expression of HMW-GS could eventually lead to improved bread-making quality by optimizing the level of over-expression or by development and characterization of additional events

The barley Lem 1 gene promoter drives expression specifically in outer floret organs at anthesis in transgenic wheat

Genetic engineering of cereal crops could be refined and made more publicly acceptable by the use of promoters that direct transgene expression to particular organs at defined stages of plant development. A fusion between the barley Lem1 promoter and green fluorescence protein was used to transform bread wheat. Expression analyses showed that the Lem1 promoter is active in the organs surrounding the wheat floret at anthesis. It is not active in other vegetative and seed tissues. The organ specificity and developmental regulation of the Lem1 promoter suggest that it would be useful for engineering Fusarium head blight resistance in wheat

Changes in High Molecular Weight Glutenin Subunit Composition Can Be Genetically Engineered without Affecting Wheat Agronomic Performance

The genomes of modern cultivars have been painstakingly selected for the presence of favorable alleles at multiple loci, which interact to produce superior phenotypes. Genetic transformation provides a tool to introduce new genes without altering the original gene combinations. However, the random genetic and epigenetic changes sometimes generated by the transformation process have been associated with losses in agronomic performance. The agronomic performance of 50 transgenic wheat (Triticum aestivum L.) lines containing additional copies of native or modified high molecular weight glutenin subunit (HMW-GS) genes and the selectable marker bar, their untransformed parent 'Bobwhite', four lines containing only bar, and 10 null segregant lines were assessed in small plot trials over 2 yr and three locations. Most of the transgenic lines did not show significant changes in performance relative to Bobwhite, although the transgenic lines as a group tended toward lower performance. Null-segregant and bar-only lines performed similarly to Bobwhite. No relationship could be established between performance and particular transgenes or their expression levels. Despite the overall lower performance of the transgenic lines, many with agronomic performance equivalent to Bobwhite were identified. These findings suggest that extant techniques for genetic engineering of wheat are capable of producing agronomically competitive lines for use as cultivars or parents in breeding programs. © Crop Science Society of America