When is the male plastome eliminated?

Abstract

PLASTOME mutations result in chloroplast defects which are inherited in a non-Mendelian manner. Because normal and defective chloroplasts can exist in the same cell and be sorted out by somatic segregation, the plastome is considered to be in the chloroplasts themselves, possibly in their DNA. A strictly maternally inherited plastid mutant in Nicotiana tabacum (status albomacu-latus) falls into this category1. The white tissues of the variegated plants contain only structurally altered chloroplasts and mitochondria, while cells with both normal and defective chloroplasts have been observed in white-green mottled tissues. Crosses among white, green and variegated inflorescences have shown that this mutation is inherited only through the egg cell and that the male plastome is lost sometime before the first division of the zygote. To investigate whether the plastome factors of the pollen mother cell can be transferred into the pollen grains and remain functional, we have grown polyhaploid plants of this plastome mutant from anthers2–4.