Transcriptomics-Based Identification of Genes Related to Tapetum Degradation and Microspore Development in Lily

Abstract

Lily is a popular and economically ornamental crop around the world. However, its high production of pollen grains causes serious problems to consumers, including allergies and staining of clothes. During anther development, the tapetum is a crucial step for pollen formation and microspore release. Therefore, it is important to understand the mechanism of tapetum degradation and microspore development in lily where free pollen contamination occurs. Here, we used the cut lily cultivar ‘Siberia’ to characterize the process of tapetum degradation through the use of cytology and transcriptomic methods. The cytological observation indicated that, as the lily buds developed from 4 cm (Lo 4 cm) to 8 cm (Lo 8 cm), the tapetum completed the degradation process and the microspores matured. Furthermore, by comparing the transcriptome profiling among three developmental stages (Lo 4 cm, Lo 6 cm and Lo 8 cm), we identified 27 differentially expressed genes. These 27 genes were classed into 4 groups by function, namely, cell division and expansion, cell-wall morphogenesis, transcription factors, LRR-RLK (leucine-rich repeat receptor-like kinases), plant hormone biosynthesis and transduction. Quantitative real-time PCR was performed as validation of the transcriptome data. These selected genes are candidate genes for the tapetum degradation and microspore development of lily and our work provides a theoretical basis for breeding new lily cultivars without pollen.

Perspective Advancements in Plant Science through Segregating Sorghum Gametophyte Developmental Stages

“…Microspores originate from the microsporocytes or pollen mother cells within the anthers of sorghum plants through the series of intricate cellular events tightly regulated by a network of genetic and hormonal cues, orchestrating the spatial and temporal expression of key developmental genes in a process called microsporogenesis [15,16]. Transcriptional profiling studies have identified several transcription factors, including MYB, bHLH, and MADS-box proteins, as well as epigenetic modifications, such as DNA methylation and histone acetylation being key regulators of the fine-tuning of gene expression during microsporogenesis [17,18]. Moreover, small RNA-mediated gene regulation, plays a pivotal role in controlling the expression of target genes involved in microspore development and differentiation or maturation process which culminates with the deposition of sporopollenin, a complex polymer essential for pollen wall formation and pollen viability [19].…”