Abstract Detail

Development and Structure

Gonzalez, Favio [1], Gonzalez, Angie [2], Alzate, Juan F [3], Pabon Mora, Natalia [4].

Evolutionary shifts of the developmental genetic networks in Pilostyles boyacensis (Apodanthaceae), a Dalea (Fabaceae) holoparasite.

Parasitism has independently evolved in most branches of the tree of life. Parasitism in the plant kingdom has been less studied than that in animals, even though drastic structural and physiological, evolutionary and genetic events occur.. Decades of comprehensive phylogenetic analyses have revealed that in flowering plants, direct penetration of the host tissue by a feeding organ called the haustorium has evolved independently 12 times. The ca. 4750 parasitic flowering plants count fornearly 2% of all angiosperm diversity, yet they exhibit some of the most extraordinary developmental, structural and reproductive strategies. The most dramatic developmental reductions occur in the endoholoparasites, which grow completely inside of their hosts as parenchymatic cells, lack typical roots, shoots and leaves, and are visible only through emerging flowers and fruits. Here we study the life cycle and floral ontogeny and differentiation of Pilostyles boyacensis, a holoparasite of the legume Dalea cuatrecasasii. P. boyacensis has no root (RAM) or shoot (SAM) apical meristems; yet, floral meristems (FM) initiate in contact to the host vascular tissue, completely inside the host, and flowers emerged having completed organogenesis. Using comparative transcriptomics, we have addressed the mechanisms through which Pilostyles maintains stem cells in the absence of primary meristems, the signals perceived for reproductive transitions in the absence of typical photoperiod sensing leaves, and the endogenous capacity for organogenesis in the dark, fully embedded inside of the host. We will present data on: 1) the substantial reduction in the SAMs genetic machinery recovering only a WUSCHEL HOMEOBOX 9 (WOX9) - BARELY ANY MERISTEM 1 (BAM1) active module for pluripotency; 2) the potential recruitment of the host flowering regulators by the holoparasite; and 3) the presence of a full set of active endogenous MADS-box floral organ identity homologs.
Funding: Universidad Nacional de Colombia, grant number 50155-2020.

1 - Universidad Nacional de Colombia, Sede Bogotá, Facultad de Ciencias, AA 7495, Bogotá, Colombia
2 - Universidad Nacional de Colombia, Departamento de Biologia, Facultad de Ciencias, Av. Carrera 30 # 45-03 Edif. 476, Bogota, 11001, Colombia
3 - Universidad de Antioquia, Facultad de Medicina, Carrera 53 # 61 - 30 , Sede de Investigacion Universitaria, Medellin, Colombia
4 - Universidad De Antioquia, Ciudad Universitaria, Aa1226, Medellin, ANT, 050010, Colombia

Andean Flora.

Presentation Type: Oral Paper
Number: DS5005
Abstract ID:680
Candidate for Awards:None

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