<p><b>(A)</b> The <i>S</i>. <i>cerevisiae</i> diploid strains MLY61a/α (WT) and XPY5a/α, a <i>TPK2Δ</i> mutant, were transformed with the <i>PbTUPA</i>, <i>ScTUP1</i> and <i>PBTPK2</i> as indicated. To allow selection, generally, constructs for the expression of the PbTupA-mRFP, ScTup1-mRFP and PbTpk2-mRFP fusion proteins were used and the transformants, selected on the basis of their fluorescence. The colonies were viewed by Leica M165 FC stereo fluorescence microscopy to identify the invasive growth on the plates. The colony views are shown both before (top panel) and after (bottom panel) washing to remove cells that had not invaded the agar. In response to the expression of PbTupA, WT cells and XPY cells transformed with <i>PbTPK2</i> produced invasive growth. XPY cells expressing PbTupA did not invade the agar, indicating that functional PbTpk2 was required for this phenotype. WT cells expressing ScTup1were non-invasive. <b>(B)</b> XPY cells expressing PbTpk2 and PbTupA developed an aerial stalk (a-c) that topples over to start a new colony (c) and to develop a second stalk (d).</p
