Programmed cell death is the cause of central cell degeneration and single fertilization in Marathrum schiedeanum (Cham.) Tul (Podostemaceae)
Por:
Jimenez-Duran, Karina, Perez-Pacheco, Monica K., Wong, Ricardo, Collazo-Ortega, Margarita, Marquez-Guzman, Judith
Publicada:
1 feb 2021
Resumen:
The Podostemaceae family is exceptional among angiosperms because of the
absence of double fertilization, a remarkable characteristic that
appears to extend to the entire family. A recent investigation of some
members of the family, including Dalzellia zeylanica (Tristichoideae),
Griffithella zeylanica, Polypleurum stylosum, Zeylanidium lichenoides,
and Zeylanidium maheshwarii (Podostemoideae), revealed that the central
cell in all of them is degenerated when the pollen tube arrives at the
synergid. In the present work, we studied the ontogenetic development of
the female gametophyte. We also conducted a terminal deoxynucleotidyl
transferase dUTP nick end labeling (TUNEL) assay and an ultrastructural
transmission electron microscopy (TEM) analysis of Marathrum schiedeanum
(Podostemoideae) to determine the causes of central cell degeneration.
The results show that in the early stage, the female gametophyte was
4-celled and 4-nucleated, but the central cell degenerated very quickly
before the start of anthesis. The reduced mature female gametophyte is
3-nucleate, 3-celled. TUNEL staining and ultrastructural TEM analysis
indicated that developmental programmed cell death (PCD) mediated the
degeneration of the central cell. The central cell displayed a
significant quantity of vacuoles containing some cellular material, and
the compact chromatin was present in the nucleus and DNA fragmentation
occurred. The factors that trigger PCD in the central cell are unknown,
but the test results confirm that pollination is not necessary for it to
occur. The death of the central cell before pollination prevents the
possibility of double fertilization and consequently results in failure
to form the endosperm.
Filiaciones:
Laboratorio de Microscopia, USAII, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, CP 04510, Mexico
Laboratorio de Desarrollo en Plantas, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, Ciudad de México, CP 04510, Mexico
Univ Nacl Autonoma Mexico, Fac Quim, USAII, Lab Microscopia, Ciudad Univ, Mexico City 04510, DF, Mexico
Univ Nacl Autonoma Mexico, Fac Ciencias, Lab Desarrollo Plantas, Ciudad Univ, Mexico City 04510, DF, Mexico
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