You are here:
Diversity and conservation in maize pollen: Phenotypes and transcripts
Citation:
Fowler, J. E., Z. Vejlupkova, L. D. Cooper, A. Qu, AND L. S. WATRUD. Diversity and conservation in maize pollen: Phenotypes and transcripts. Presented at Frontiers of sexual plant reproduction III, Tucson, AZ, October 17 - 19, 2008.
Impact/Purpose:
In addition to its crucial role in seed production, pollen serves as a vector for gene flow between plant populations.
Description:
In addition to its crucial role in seed production, pollen serves as a vector for gene flow between plant populations. Recently, pollen was identified as a mechanism for introduction of transgenes into non-transgenic populations. To investigate the genetic basis for pollen fitness, which likely influences pollen-mediated gene flow, we are documenting phenotypic and transcriptomic variation in pollen from a set of diverse maize lines. At the phenotypic level, we have measured pollen competitive ability (PCA) in 19 lines using a pollen-mixing method employed previously by Sari-Gorla, Ottaviano, Pé and co-workers. We found a range of significant differences in PCA among maize inbreds. Furthermore, pollen from three out of four hybrids tested ranked as the most competitive, consistent with earlier work indicating correlation between sporophytic vigor and pollen fitness (reviewed in Ottaviano & Mulcahy 1989). At the transcriptomic level, microarrays were used to assess gene expression in seedling, mature pollen and germinated pollen samples from two different inbred lines (B73 and W22). As expected, a large number of probes (~10,000) showed significant expression differences between pollen and seedling; a smaller number of probes (~1000) showed significant differences between the two inbred lines in both pollen and seedling, although these were largely non-overlapping sets. Quantitative RT-PCR experiments are being used to validate these results. Interestingly, at a stringent statistical cutoff, the microarray data found no significant differences between mature and germinated pollen. Finally, we have used our data to help identify a set of conserved pollen-enriched genes in maize, rice and Arabidopsis.