Stability of Transgene Inheritance in Progeny of Field-Grown Pear Trees over a 7-Year Period

Lebedev, V. T.

doi:10.3390/plants11020151

Cited by 3 publications

(3 citation statements)

References 61 publications

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“…The level of IME in these parts of the fruit was, on average twofold, which is comparable to the IME in leaves. The increased level of expression of the uidA gene with an intron also persisted during vegetative [ 52 ] and seed [ 53 ] propagation of transgenic pear plants.…”

Section: Discussionmentioning

confidence: 99%

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Impact of Intron and Retransformation on Transgene Expression in Leaf and Fruit Tissues of Field-Grown Pear Trees

Lebedev

2023

IJMS

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Stable and high expression of introduced genes is a prerequisite for using transgenic trees. Transgene stacking enables combining several valuable traits, but repeated transformation increases the risk of unintended effects. This work studied the stability and intron-mediated enhancement of uidA gene expression in leaves and different anatomical parts of pear fruits during field trials over 14 years. The stability of reporter and herbicide resistance transgenes in retransformed pear plants, as well as possible unintended effects using high-throughput phenotyping tools, were also investigated. The activity of β-glucuronidase (GUS) varied depending on the year, but silencing did not occur. The uidA gene was expressed to a maximum in seeds, slightly less in the peel and peduncles, and much less in the pulp of pear fruits. The intron in the uidA gene stably increased expression in leaves and fruits by approximately twofold. Retransformants with the bar gene showed long-term herbicide resistance and exhibited no consistent changes in leaf size and shape. The transgenic pear was used as rootstock and scion, but grafted plants showed no transport of the GUS protein through the graft in the greenhouse and field. This longest field trial of transgenic fruit trees demonstrates stable expression under varying environmental conditions, the expression-enhancing effect of intron and the absence of unintended effects in single- and double-transformed woody plants.

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Section: Discussionmentioning

confidence: 99%

“…The trees were managed according to standard practice for pear fruit production, including pruning, fertilization, irrigation, and pesticide treatment. Fruits were obtained by hand pollination of flowers from control and transgenic trees using mixed pollen of commercial pear cultivars [ 53 ] and harvested at the maturity stage (mid-August).…”

Section: Methodsmentioning

confidence: 99%

Impact of Intron and Retransformation on Transgene Expression in Leaf and Fruit Tissues of Field-Grown Pear Trees

Lebedev

2023

IJMS

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“…Generally, standard breeding programs still offer the possibility to release new improved pear cultivars and rootstocks but always with long production times and with the difficulty of solving specific problems of a cultivar without losing its main peculiarities. In fact, conventional breeding is difficult and demands several years because of pear, as perennial fruit species, is characterized by a high level of heterozygosity and a long juvenile period (4-6 years) (Caboni et al 1999;Rivalta et al 2002;Prohens et al 2022). Thus, New Genomic Techniques (NGTs) based on the use of different biotechnological tools offer the possibility to improve, in shorter time, the existing and well-known pear commercial rootstocks and cultivars by modifying specific traits to obtain plants with higher production capacity and fruits nutritionally improved (Sabbadini et al 2021).…”

Section: Introductionmentioning

confidence: 99%

In vitro shoot regeneration from leaves of Pyrus communis L. rootstock and cultivars

Ricci

Mezzetti

Navacchi

et al. 2023

Plant Biotechnol Rep

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The influence of TDZ on adventitious shoot regeneration from leaves of the pear cultivars Conference and Abate Fétel, and the rootstock Farold®87 was investigated. Our main aim was to set up efficient in vitro regeneration protocols for all these pear genotypes by using expanding leaves from elongated shoot cultures as starting plant material. Our best results in terms of percentage of regeneration were achieved by using half-strength Murashige and Skoog basal medium supplemented with 1 μM NAA, combined with 13.5 μM TDZ for Conference (87.3%) and Farold®87 (53.3%), and 9 μM TDZ for Abate Fétel (68%). The impact on leaf organogenesis of the antibiotics timentin, cefotaxime, and carbenicillin, alone or in combination, usually used for the control of Agrobacterium overgrowth, and of kanamycin, commonly used for the selection of putatively transformed plants, were also evaluated to be exploited in future transformation trials. In general, the use of carbenicillin (475 mM), cefotaxime/carbenicillin (210/238 mM) and cefotaxime (630 mM) did not negatively affect the regeneration efficiency of Conference, Abate Fétel and Farold®87, respectively. The use of 4 μM kanamycin should be suitable to select transformed shoots from Abate Fétel and Farold®87 leaves, while a lower concentration or a different selection strategy should be applied for Conference. We report new regeneration and selection protocols usable for the application of new biotechnologies in the genetic improvement of pear cultivars and rootstocks.

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AGAMOUS regulates various target genes via cell cycle–coupled H3K27me3 dilution in floral meristems and stamens

et al. 2023

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The MADS domain transcription factor AGAMOUS (AG) regulates floral meristem termination by preventing maintenance of the histone modification H3K27me3 along the KNUCKLES (KNU) coding sequence. At two days after AG binding, cell division has diluted the repressive mark H3K27me3, allowing activation of KNU transcription prior to floral meristem termination. However, how many other downstream genes are temporally regulated by this intrinsic epigenetic timer and what their functions are remain unknown. Here, we identify direct AG targets regulated through cell cycle–coupled H3K27me3 dilution in Arabidopsis thaliana. Expression of the targets KNU, AT HOOK MOTIF NUCLEAR LOCALIZED PROTEIN18 (AHL18), and PLATZ10 occurred later in plants with longer H3K27me3-marked regions. We established a mathematical model to predict timing of gene expression and manipulated temporal gene expression using the H3K27me3-marked del region from the KNU coding sequence. Increasing the number of del copies delayed and reduced KNU expression in a Polycomb Repressive Complex 2– and cell cycle–dependent manner. Furthermore, AHL18 was specifically expressed in stamens and caused developmental defects when mis-expressed. Finally, AHL18 bound to genes important for stamen growth. Our results suggest that AG controls the timing of expression of various target genes via cell cycle–coupled dilution of H3K27me3 for proper floral meristem termination and stamen development.

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Stability of Transgene Inheritance in Progeny of Field-Grown Pear Trees over a 7-Year Period

Cited by 3 publications

References 61 publications

Impact of Intron and Retransformation on Transgene Expression in Leaf and Fruit Tissues of Field-Grown Pear Trees

Impact of Intron and Retransformation on Transgene Expression in Leaf and Fruit Tissues of Field-Grown Pear Trees

In vitro shoot regeneration from leaves of Pyrus communis L. rootstock and cultivars

AGAMOUS regulates various target genes via cell cycle–coupled H3K27me3 dilution in floral meristems and stamens

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