Original Article

Planta

, Volume 235, Issue 6, pp 1239-1251

First online:

Development of a transgenic early flowering pear (Pyrus communis L.) genotype by RNAi silencing of PcTFL1-1 and PcTFL1-2

  • Aviad FreimanAffiliated withInstitute of Plant Sciences, Agricultural Research OrganizationThe Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem
  • , Lyudmila ShlizermanAffiliated withInstitute of Plant Sciences, Agricultural Research Organization
  • , Sara GolobovitchAffiliated withInstitute of Plant Sciences, Agricultural Research Organization
  • , Zeev YablovitzAffiliated withInstitute of Plant Sciences, Agricultural Research Organization
  • , Raia KorchinskyAffiliated withInstitute of Plant Sciences, Agricultural Research Organization
  • , Yuval CohenAffiliated withInstitute of Plant Sciences, Agricultural Research Organization
  • , Alon SamachAffiliated withThe Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem
  • , Elisabeth ChevreauAffiliated withINRA, Institut de Recherche en Horticulture et Semences (INRA, Agrocampus-Ouest, Université d’Angers)
  • , Pierre-Marie Le RouxAffiliated withAgroscope Changins-Wädenswil Research Station (ACW)
    • , Andrea PatocchiAffiliated withAgroscope Changins-Wädenswil Research Station (ACW)
    • , Moshe A. FlaishmanAffiliated withInstitute of Plant Sciences, Agricultural Research Organization Email author 

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Abstract

Trees require a long maturation period, known as juvenile phase, before they can reproduce, complicating their genetic improvement as compared to annual plants. ‘Spadona’, one of the most important European pear (Pyrus communis L.) cultivars grown in Israel, has a very long juvenile period, up to 14 years, making breeding programs extremely slow. Progress in understanding the molecular basis of the transition to flowering has revealed genes that accelerate reproductive development when ectopically expressed in transgenic plants. A transgenic line of ‘Spadona’, named Early Flowering-Spadona (EF-Spa), was produced using a MdTFL1 RNAi cassette targeting the native pear genes PcTFL1-1 and PcTFL1-2. The transgenic line had three T-DNA insertions, one assigned to chromosome 2 and two to chromosome 14 PcTFL1-1 and PcTFL1-2 were completely silenced, and EF-Spa displayed an early flowering phenotype: flowers developed already in tissue culture and on most rooted plants 1–8 months after transfer to the greenhouse. EF-Spa developed solitary flowers from apical or lateral buds, reducing vegetative growth vigor. Pollination of EF-Spa trees generated normal-shaped fruits with viable F1 seeds. The greenhouse-grown transgenic F1 seedlings formed shoots and produced flowers 1–33 months after germination. Sequence analyses, of the non-transgenic F1 seedlings, demonstrated that this approach can be used to recover seedlings that have no trace of the T-DNA. Thus, the early flowering transgenic line EF-Spa obtained by PcTFL1 silencing provides an interesting tool to accelerate pear breeding.

Keywords

Genetic transformation Juvenility Plant breeding Precocious flowering MdTFL1