Analysis of<i>sticky generative cell</i>mutants reveals that suppression of callose deposition in the generative cell is necessary for generative cell internalization and differentiation in<i>Arabidopsis</i>

In flowering plants, double fertilization between male and female gametophytes, which are separated by distance, largely depends on the unique pattern of gametophyte (pollen): two non-motile sperm cells suspended within a tube-producing vegetative cell. A morphological screen to elucidate genetic control governing strategic patterning pollen has led isolation sticky generative cell (sgc) mutant that dehisces abnormal with immobilized at wall. Analyses revealed sgc mutation is specifically detrimental development, causing ectopic callose deposition impedes timely internalization differentiation We found SGC gene encodes highly conserved domain unknown function 707 (DUF707) broadly expressed but germline specific during development. Additionally, transgenic plants co-expressing fluorescently fused protein known organelle markers showed localizes in endoplasmic reticulum, Golgi apparatus vacuoles pollen. yeast two-hybrid an bait identified thaumatin-like we named GCTLP1, some homologs bind and/or digest ?-1,3-glucans, main constituent callose. GCTLP1 germline-specific manner colocalizes indicating putative interactor. Collectively, our results show suppresses nascent cell, thereby allowing fully internalize into correctly differentiate as progenitor, potential involvement protein, development Arabidopsis.