Comparative Transcriptome Analysis Reveals Gene Regulatory Mechanism of UDT1 on Anther Development

The tapetum plays a crucial role in pollen development by nursing and releasing the microspore. The tapetum undergoes programmed cell death (PCD), and appropriate timing of PCD is essential for microsporogenesis. Undeveloped Tapetum1 (UDT1) is known to function in anther development, but the regulation mechanism of tapetum differentiation and degeneration by UDT1 is largely unknown. Through comparative transcriptome analysis, we selected 100 genes as udt1 downregulated genes. The biological process related to the negative regulation of translation is the most enriched in udt1 downregulated genes. It is attributed by ribosome inactivating proteins (RIPs), but the role of RIPs is not well defined, and they are assumed to participate in tapetal PCD. Lipid transport is another overrepresented Gene Ontology (GO) term in udt1 downregulated genes, indicating the functional loss of the tapetum as the nursing cell. Using comparative analysis and real-time PCR, we infer that UDT1 can trigger tapetal PCD by controlling the expression of RIPs and three aspartyl proteases (AP) grouped with OsAP37, which is well known as being involved in tapetum degeneration.