Roles for polarity and nuclear determinants in specifying daughter cell fates after an asymmetric cell division in the maize leaf

Asymmetric cell divisions occur repeatedly during plant development, but th e mechanisms by which daughter cells are directed to adopt different fates are not well understood [1,2], Previous studies have demonstrated roles for positional information in specification of daughter cell fates following a symmetric divisions in the embryo [3] and root [4], Unequally inherited cyt oplasmic determinants have also been proposed to specify daughter cell fate s after some asymmetric cell divisions in plants [1,2,5], but direct eviden ce is lacking. Here we investigate the requirements for specification of st omatal subsidiary cell fate in the maize leaf by analyzing four mutants dis rupting the asymmetric divisions of subsidiary mother cells (SMCs). We show that subsidiary cell fate does not depend on proper localization of the ne w cell wall during the SMC division, and is not specified by positional inf ormation acting on daughter cells after completion of the division. Instead , our data suggest that specification of subsidiary cell fate depends on po larization of SMCs and on inheritance of the appropriate daughter nucleus. We thus provide evidence of a role for unequal inheritance of an intracellu lar determinant in specification of cell fate after an asymmetric plant cel l division. (C) 2000 Elsevier Science Ltd. All rights reserved.