Senescence Associated Genes Modulating Programmed Cell Death in Plant Leaves

The aim of this study was to evaluate the effects of various promoters and inhibitors of leaf senescence in Rosa hybrida by applying different concentrations of plant hormones under controlled tissue culture conditions. The study sought to identify hormonal treatments that can delay or accelerate senescence, with the goal of improving the postharvest quality and longevity of rose foliage. The plants were grown by tissue culture techniques, which were free from disease. Regenerated plants with well-defined leaves, were infiltrated with hormones and the untreated plant leaves used as control. After the infiltration, all plants were kept under growth conditions at 25±2ºC and phonotypical characteristics were observed regularly. Further, the round discs of rose leaves were prepared from two opposite of same sized leaves collected from tissue cultured plants and discs of same size were made. Molecular studies were performed on discs of leaves for further clarification involved regulatory mechanism. The results showed various narrative phenotypes with elevated level of transcripts. The phenotype was characterized by yellowing of leaves, observed in both treated and untreated samples. Notably, leaves treated with Ethylene, ABA, and NaCl exhibited more pronounced yellowing, particularly in the lower regions of the plants, accompanied by a reduced number of tillers at the plant base. To assess the senescence progression level, key markers gene expression of SAG12 (a senescence-associated gene) and photosynthesis-associated genes (PS), as well as content of chlorophyll and leakage of ions were analyzed. The results highlighted that hormonal treatments play a significant role in regulating leaf senescence. Promoter treatments accelerated the onset of senescence and reduced chlorophyll content, while inhibitor treatments preserved chlorophyll levels and delayed the senescence process. Furthermore, photosynthesis, essential for plant growth and development, was significantly disrupted in promoter-treated leaves, underscoring the pivotal influence of hormonal regulation on senescence