Department of Chemical Biology, National Pingtung University of Education, Pingtung, 90003, Taiwan, ROC.
Plant Cell Physiol. 2011 Sep;52(9):1546-59. doi: 10.1093/pcp/pcr095. Epub 2011 Jul 19.
Pollination is composed of cell-cell communication and complicated signaling cascades that regulate pollen tube growth and guidance toward the ovules for double fertilization, and is critical for successful sexual reproduction. Exploring expression profiles of in vivo grown pollen tubes is important. Nevertheless, it is difficult to obtain accessible pollen tubes for profiling studies in most model plants. By taking advantage of the hollow styles of lily (Lilium longiflorum), in vivo pollen tubes harvested from pollinated styles which had been cut open were used here to study their protein and transcript profiles. Pollination quantitatively and qualitatively altered the total protein composition of elongating pollen tubes. cDNAs generated and amplified from total RNAs of 24 h in vivo grown and 12 h in vitro cultured pollen tubes were used for suppression subtractive hybridization analyses and preparation of home-made array chips. Microarray analyses conducted with different probe sets revealed 16 transcripts specifically present and/or enriched in in vivo pollen tubes. Reverse transcription-PCR (RT-PCR), in situ hybridization and Northern blotting were applied to validate their unique pollination-induced expression features. Interestingly, several transcripts were simultaneously detected on the stylar transmitting tract epidermis, where in vivo pollen tubes tightly adhered during pollination. Their deduced amino acid sequences showed that most of them encoded small proteins and could be classified into several families. Transient assay revealed filament-like structures decorated by these proteins and one probably localized in the generative cell. These small peptides might be critical for pollen tube growth during pollination, and further exploration of their biological functions and mechanisms of action are of great interest.
授粉是由细胞间通讯和复杂的信号级联组成的，它们调节花粉管的生长并引导花粉管向胚珠进行双受精，对于成功的有性繁殖至关重要。探索体内生长的花粉管的表达谱很重要。然而，在大多数模式植物中，很难获得可用于分析的易于接近的花粉管。利用百合（Lilium longiflorum）的空心花柱，这里从已切开的授粉花柱中收获体内授粉的花粉管，用于研究它们的蛋白质和转录本谱。授粉在数量和质量上改变了伸长花粉管的总蛋白质组成。从 24 小时体内生长和 12 小时体外培养的花粉管的总 RNA 中生成和扩增的 cDNA，用于抑制性消减杂交分析和制备自制阵列芯片。使用不同探针组进行的微阵列分析显示，16 个转录本特异性存在于体内花粉管中或在体内花粉管中富集。逆转录 -PCR（RT-PCR）、原位杂交和 Northern 印迹用于验证它们独特的授粉诱导表达特征。有趣的是，几个转录本同时在花柱传递道表皮上被检测到，在授粉期间，体内花粉管紧紧地附着在那里。它们推导的氨基酸序列表明，它们中的大多数编码小蛋白，并可以分为几个家族。瞬时测定显示这些蛋白质修饰的丝状结构，其中一种可能定位于生殖细胞中。这些小肽可能在授粉期间对花粉管的生长至关重要，进一步探索它们的生物学功能和作用机制非常有趣。
