Jasmonate Acid Involved In Tuber Development Of Potato In Vitro

Potato(Solanum tuberosum L.) is the fourth most important crop. The development of potato tuber, as a nutrient storage organ, not only is related to temperature, light, nitrogen levels and hormone, but also involved in the complex signal transduction and regulation. Hormonal regulation is one of the key signal regulations of tuber development. The mechanisms of potato tubers development in vitro were regulated by jasmonic acid signal. But the signal pathway and fuctionnal target were still not clear.In present study, the morphological, physiological and proteomic methods were used to investigate the mechanism under different exogenous methyl jasmonate treatments. The results were as follows:Stolons promoted the formation of tuber and increased biomass accumulation by methyl jasmonate in vitro. The low concentration of methyl jasmonate(0.5, 5 μΜ) promoted the formation and development of tuber in vitro. Conversely, high concentration(50 μΜ) inhibited the formation and development of tuber in vitro. The content of starch and soluble sugar increased and then decreased in tuber in vitro under methyl jasmonate treatments, but the level of reducing sugar decreased. These results suggested that methyl jasmonate promoted the formation and development of tuber in vitro.The activities of lipoxygenase and superoxide dismutase gradually were increased in vitro tuber under methyl jasmonate treatment. The activity of ascorbate peroxidase and catalase increased and then decreased. Due to low concentrations of methyl jasmonate(0.5, 5 μΜ) increased activity of lipoxygenase and promoted the formation of tuber in vitro, whereas high concentrations of methyl jasmonate(50 μΜ) inhibited the formation and development of tuber in vitro. Reactive oxygen species signal and methyl jasmonate signal cross-talking maybe happen in the formation and development of tuber in vitro.There was no significant difference in the number of protein spots among the treament of 0 μΜMe JA(1398±46), 0.5 μΜMe JA(1170±69), 5 μΜMe JA(1224±55) and 5 μΜMe JA(1265±72). Thirty-five different expressed protein spots were detected in under methyl jasmonate treatments. Those differentially expressed proteins involved in different pathways, including bioenergy and metabolism, cell defense and rescue, transcription related, cell signaling and protein destination and storage. In these spots, twenty-one spots were up-regulated or down-regulated, ten spots were up-regulated after down-regulated or down-regulated after up-regulated, four spots were new-induced.Proteins induced by methyl jasmonate involved in the processes of tuber formation and development in vitro. First, methyl jasmonate promoted the flow of carbon source to glycolysis, glyoxylate cycle, TCA cycle way, and also promoted the synthesis of long chain fatty acids. Second, methyl jasmonate promoted the growth and development of potato tubers by eliminated and transformed the development of toxic substances in vitro. Third, methyl jasmonate induced certain signal molecules and regulated protein degradation or folding to control the formation and development of tubers.