SPECIFIC DISTRIBUTION OF MESSENGER-RNAS IN MAIZE GROWING POLLEN TUBESOBSERVED BY WHOLE-MOUNT IN-SITU HYBRIDIZATION WITH NONRADIOACTIVE PROBES

The distribution of a number of specific mRNAs has been observed in ma ize growing pollen tubes. Whole-mount in situ hybridization using digo xygenin-labelled RNA probes has been tested. The technique appears to be a simple, rapid and reliable method in this system, in immature ant hers and also in other tissues. Results for three probes are presented . They correspond to a hydroxyproline-rich glycoprotein (HRGP), an abu ndant component of the maize cell wall, to an alpha-tubulin (encoded b y the Tub alpha 1 gene) highly expressed in the radicular system of th e plant and also in pollen, and to an isoform of the malic enzyme, inv olved in the basic metabolism of the plant. The mRNAs corresponding to these three proteins are differently distributed in the germinating p ollen. While HRGP mRNA is only present in the tube, malic enzyme mRNA is only present in the body of the pollen cell, and alpha-tubulin mRNA is present in both parts of the cell but shows a higher accumulation in the tip of the pollen tube.