Identification of senescence-associated genes in broccoli (Brassica oleracea) following harvest
Yogesh Ahlawat, Song Li, Prakash R. Timilsena, Eleni D. Pliakoni, Jeffrey K. Brecht and Tie Liu
Postharvest Biology and Technology, Volume 183, January 2022, 111729
2022
บทคัดย่อ
We used genomic tools to understand senescence and molecular signaling events in harvested broccoli florets stored at 25 or 4 °C to test the hypothesis that genetic markers can be used to identify the stage of senescence or physiological age of plant tissue. The RNA-sequencing approach provided key insights into the gradual changes in transcriptome during postharvest storage in broccoli. We found that 4279 and 4143 transcripts were differentially expressed after 3 and 5 days of storage at the two storage temperatures, respectively. We then performed genome-wide comparisons at 25 and 4 °C and illustrated the temporal and spatial-specific genes in stored broccoli. By using quantitative Real-Time PCR and transient tobacco assay, we validated our RNA-sequencing experiment. We further performed comparative analysis of Arabidopsis and broccoli to disclose conserved senescence genes. Concurrently, we found that 43 genes were senescence-specific genes that are common senescence-associated genes (SAGs) regardless of tissue-specific expression. Interestingly, we observed 73 transcription factors (TFs) within this group that might form a core transcriptional regulatory circuitry to control the onset and progression of senescence. Moreover, we also identified new molecular players involved in postharvest senescence including brassinosteroids (BR) perception genes, BIK1 (Brassinosteroid-Interacting Kinase1), BRL1 (BRI1-like 1), BIR1 (BAK1-Inteacting Receptor-Like Kinase 1), stomatal patterning gene SPCH, and circadian clock genes CCA1. Those genes could serve as ‘freshness-indicators’ for the stage of senescence or relative freshness of the product. This report identified the SAGs that are essential for tissue-specific senescence and provided fundamental insights into signaling events during postharvest senescence in Brassica plants.