Avtar K. Handa Purdue University

SEMINAR

Spermidine, an elixir for enhancing fruit quality and vegetation longevity

Senescence and aging are inevitable processes of biological life. A desire to develop an elixir to overcome these processes is as old as the development of inquisitive reasoning among Homo sapiens. The multitude of processes such as redox imbalance, genomic instability, low-grade inflammation, dysregulation of immune system, excessive calorie intake, inactivity /sedentary life styles and telomere shortening have been implicated to contribute to these processes. Last few decades have seen significant advancement in understanding molecular signals that promote longevity in mammals that include sirutin activators resveratrol and fisetin, target of rapamycin inhibitors, curcumin, hyphen a NF-κB inhibitor and spermidine - a histone acetyltransferases inhibitor. Emerging evidence indicates that decreasing intracellular polyamine levels exerts a strong influence on aging of yeast, fruit fly, worms, mice, human cells and fruits. Biogenic amines are ubiquitous and essential for cells viability and influence myriad of growth and development processes in all organisms including plants. Our research have shown that genetic enhancement of spermidine and spermine during tomato fruit ripening increases the levels of antioxidant lycopene, enhances on planta fruit life, reduces postharvest shriveling and decay, and improves juice quality. In addition, the whole plant seasonal senescence was found to be delayed, thus leading to a longer crop productivity period. Collectively, our results showed that these biogenic amines significantly enhanced whole plant and fruit quality and shelf lives. Our transcriptome and metabolome analyses showed that polyamines restore and enhance metabolic memory in ripening fruit and cross talk with biosynthetic and signaling pathways of several plant hormones. Our results indicate that spermidine and spermine are positive regulators of various metabolic and physiological parameters whereas putrescine exerts negative influence on these processes. I will discuss these results in light of hypothesis that spermidine is an elixir that improves plant growth and developmental process.

October 29, 3:30 pm HORT 117 Reception at 3:10 pm HORT 117

Department of Horticulture and Landscape Architecture